mikroC Users Manual - University of Hertfordshire School of

mikroC Users Manual - University of Hertfordshire School of
mikroElektronika
C Compiler for Microchip PIC microcontrollers
mikroC
Making it simple
mikro
User’s manual
Development tools - Books - Compilers
www.mikroe.com
ICD
Develop your applications quickly and easily with the world's
most intuitive C compiler for PIC Microcontrollers (families
PIC12, PIC16, and PIC18).
IN-CIRCUIT
Highly sophisticated IDE provides the power you need with the
simplicity of a Windows based point-and-click environment.
SUPPORTED
from V6.0
With useful implemented tools, many practical code examples,
broad set of built-in routines, and a comprehensive Help, mikroC
makes a fast and reliable tool, which can satisfy needs of experienced engineers and beginners alike.
DEBUGGER
mikroC
mikroC - C Compiler for Microchip PIC microcontrollers
making it simple...
Reader’s note
DISCLAIMER:
mikroC and this manual are owned by mikroElektronika and are protected by copyright law
and international copyright treaty. Therefore, you should treat this manual like any other copyrighted material (e.g., a book). The manual and the compiler may not be copied, partially or
as a whole without the written consent from the mikroEelktronika. The PDF-edition of the
manual can be printed for private or local use, but not for distribution. Modifying the manual
or the compiler is strictly prohibited.
HIGH RISK ACTIVITIES
The mikroC compiler is not fault-tolerant and is not designed, manufactured or intended for
use or resale as on-line control equipment in hazardous environments requiring fail-safe performance, such as in the operation of nuclear facilities, aircraft navigation or communication
systems, air traffic control, direct life support machines, or weapons systems, in which the failure of the Software could lead directly to death, personal injury, or severe physical or environmental damage ("High Risk Activities"). mikroElektronika and its suppliers specifically disclaim any express or implied warranty of fitness for High Risk Activities.
LICENSE AGREEMENT:
By using the mikroC compiler, you agree to the terms of this agreement. Only one person
may use licensed version of mikroC compiler at a time.
Copyright © mikroElektronika 2003 - 2006.
This manual covers mikroC version 6.2.0 and the related topics. Newer versions may contain changes without prior notice.
COMPILER BUG REPORTS:
The compiler has been carefully tested and debugged. It is, however, not possible to
guarantee a 100 % error free product. If you would like to report a bug, please contact us at
the address [email protected] Please include next information in your bug report:
- Your operating system
- Version of mikroC
- Code sample
- Description of a bug
CONTACT US:
mikroElektronika
Voice: + 381 (11) 30 66 377, + 381 (11) 30 66 378
Fax:
+ 381 (11) 30 66 379
Web:
www.mikroe.com
E-mail: [email protected]
PIC, PICmicro and MPLAB is a Registered trademark of Microchip company. Windows is a
Registered trademark of Microsoft Corp. All other trade and/or services marks are the
property of the respective owners.
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mikr oC User ’s manual
Table of Contents
CHAPTER 1
mikroC IDE
CHAPTER 2
Building Applications
CHAPTER 3
mikroC Reference
CHAPTER 4
mikroC Libraries
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mikroC - C Compiler for Microchip PIC microcontrollers
CHAPTER 1: mikroC IDE
1
Quick Overview
Code Editor
Code Explorer
Debugger
Error Window
Statistics
Integrated Tools
Keyboard Shortcuts
1
3
6
7
11
12
15
19
CHAPTER 2: Building Applications
21
Projects
Source Files
Search Paths
Managing Source Files
Compilation
Output Files
Assembly View
Error Messages
22
24
24
25
27
27
27
28
CHAPTER 3: mikroC Language Reference
31
PIC Specifics
mikroC Specifics
ANSI Standard Issues
Predefined Globals and Constants
Accessing Individual Bits
Interrupts
Linker Directives
Code Optimization
Indirect Function Calls
Lexical Elements
mikro ICD (In-Circuit Debugger)
mikro ICD Debugger Options
mikro ICD Debugger Example
mikro ICD Overview
Tokens
Constants
Integer Constants
Floating Point Constants
Character Constants
String Constants
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Enumeration Constants
Pointer Constants
Constant Expressions
Keywords
Identifiers
Punctuators
Objects and Lvalues
Scope and Visibility
Name Spaces
Duration
Types
Fundamental Types
Arithmetic Types
Enumeration Types
Void Type
Derived Types
Arrays
Pointers
Function Pointer
Pointer Arithmetic
Structures
Unions
Bit Fields
Types Conversions
Standard Conversions
Explicit Typecasting
Declarations
Linkage
Storage Classes
Type Qualifiers
Typedef Specifier
asm Declaration
Initialization
Functions
Function Declaration
Function Prototypes
Function Definition
Function Reentrancy
Function Calls
Ellipsis Operator
Operators
Precedence and Associativity
Arithmetic Operators
Relational Operators
Bitwise Operators
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Logical Operators
Conditional Operator ? :
Assignment Operators
sizeof Operator
Expressions
Statements
Labeled Statements
Expression Statements
Selection Statements
Iteration Statements
Jump Statements
Compound Statements (Blocks)
Preprocessor
Preprocessor Directives
Macros
File Inclusion
Preprocessor Operators
Conditional Compilation
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CHAPTER 4: mikroC Libraries
155
Built-in Routines
Library Routines
ADC Library
CAN Library
CANSPI Library
Compact Flash Library
Compact Flash Flash FAT Library v2.xx
EEPROM Library
Ethernet Library
SPI Ethernet Library
Flash Memory Library
I2C Library
Keypad Library
LCD Library (4-bit interface)
LCD Custom Library (4-bit interface)
LCD8 Library (8-bit interface)
Graphic LCD Library
T6963C Graphic LCD Library
Manchester Code Library
Multi Media Card Library
OneWire Library
PS/2 Library
PWM Library
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RS-485 Library
Software I2C Library
Software SPI Library
Software UART Library
Sound Library
SPI Library
USART Library
USB HID Library
Util Library
ANSI C Ctype Library
ANSI C Math Library
ANSI C Stdlib Library
ANSI C String Library
Conversions Library
Trigonometry Library
Sprint Library
SPI Graphic LCD Library
Port Expander Library
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Contact Us
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CHAPTER
1
mikroC IDE
QUICK OVERVIEW
mikroC is a powerful, feature rich development tool for PICmicros. It is designed
to provide the customer with the easiest possible solution for developing applications for embedded systems, without compromising performance or control.
PIC and C fit together well: PIC is the most popular 8-bit chip in the world, used
in a wide variety of applications, and C, prized for its efficiency, is the natural
choice for developing embedded systems. mikroC provides a successful match
featuring highly advanced IDE, ANSI compliant compiler, broad set of hardware
libraries, comprehensive documentation, and plenty of ready-to-run examples.
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Watch
Window
Code
Explorer
Code
Editor
Project
Summary
Error
Window
Code
Assistant
mikroC allows you to quickly develop and deploy complex applications:
- Write your C source code using the highly advanced Code Editor
- Use the included mikroC libraries to dramatically speed up the development:
data acquisition, memory, displays, conversions, communications…
- Monitor your program structure, variables, and functions in the Code Explorer.
Generate commented, human-readable assembly, and standard HEX compatible
with all programmers.
- Inspect program flow and debug executable logic with the integrated Debugger.
Get detailed reports and graphs on code statistics, assembly listing, calling tree…
- We have provided plenty of examples for you to expand, develop, and use as
building bricks in your projects.
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CODE EDITOR
The Code Editor is an advanced text editor fashioned to satisfy the needs of professionals. General code editing is same as working with any standard text-editor,
including familiar Copy, Paste, and Undo actions, common for Windows environment.
Advanced Editor features include:
- Adjustable Syntax Highlighting
- Code Assistant
- Parameter Assistant
- Code Templates (Auto Complete)
- Auto Correct for common typos
- Bookmarks and Goto Line
You can customize these options from the Editor Settings dialog. To access the
settings, choose Tools > Options from the drop-down menu, or click the Tools
icon.
Tools Icon.
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Code Assistant [CTRL+SPACE]
If you type a first few letter of a word and then press CTRL+SPACE, all the valid
identifiers matching the letters you typed will be prompted in a floating panel (see
the image). Now you can keep typing to narrow the choice, or you can select one
from the list using the keyboard arrows and Enter.
Parameter Assistant [CTRL+SHIFT+SPACE]
The Parameter Assistant will be automatically invoked when you open a parenthesis "(" or press CTRL+SHIFT+SPACE. If name of a valid function precedes the
parenthesis, then the expected parameters will be prompted in a floating panel. As
you type the actual parameter, the next expected parameter will become bold.
Code Template [CTR+J]
You can insert the Code Template by typing the name of the template (for
instance, whileb), then press CTRL+J, and the Code Editor will automatically
generate the code. Or you can click a button from the Code toolbar and select a
template from the list.
You can add your own templates to the list. Just select Tools > Options from the
drop-down menu, or click the Tools Icon from Settings Toolbar, and then select
the Auto Complete Tab. Here you can enter the appropriate keyword, description,
and code of your template.
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Auto Correct
The Auto Correct feature corrects common typing mistakes. To access the list of
recognized typos, select Tools > Options from the drop-down menu, or click the
Tools Icon, and then select the Auto Correct Tab. You can also add your own preferences to the list.
Comment/Uncomment
Comment /
Uncomment Icon.
The Code Editor allows you to comment or uncomment selected block of code by
a simple click of a mouse, using the Comment/Uncomment icons from the Code
Toolbar.
Bookmarks
Bookmarks make navigation through large code easier.
CTRL+<number> : Go to a bookmark
CTRL+SHIFT+<number> : Set a bookmark
Goto Line
Goto Line option makes navigation through large code easier. Select Search >
Goto Line from the drop-down menu, or use the shortcut CTRL+G.
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CODE EXPLORER
The Code Explorer is placed to the left of the main window by default, and gives a
clear view of every declared item in the source code. You can jump to a declaration of any item by clicking it, or by clicking the Find Declaration icon. To expand
or collapse treeview in Code Explorer, use the Collapse/Expand All icon.
Collapse/Expand
All Icon.
Also, two more tabs are available in Code Explorer. QHelp Tab lists all the available built-in and library functions, for a quick reference. Double-clicking a routine
in QHelp Tab opens the relevant Help topic. Keyboard Tab lists all the available
keyboard shortcuts in mikroC.
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DEBUGGER
The source-level Debugger is an integral component of mikroC development environment. It is designed to simulate operations of Microchip Technology's
PICmicros and to assist users in debugging software written for these devices.
Start Debugger
The Debugger simulates program flow and execution of instruction lines, but does
not fully emulate PIC device behavior: it does not update timers, interrupt flags,
etc.
After you have successfully compiled your project, you can run the Debugger by
selecting Run > Debug from the drop-down menu, or by clicking the Debug Icon .
Starting the Debugger makes more options available: Step Into, Step Over, Run to
Cursor, etc. Line that is to be executed is color highlighted.
Debug [F9]
Start the Debugger.
Pause Debugger
Step Into
Step Over
Step Out
Run/Pause Debugger [F6]
Run or pause the Debugger.
Step Into [F7]
Execute the current C (single– or multi–cycle) instruction, then halt. If the instruction is a routine call, enter the routine and halt at the first instruction following the
call.
Step Over [F8]
Execute the current C (single– or multi–cycle) instruction, then halt. If the instruction is a routine call, skip it and halt at the first instruction following the call.
Step Out [Ctrl+F8]
Execute the current C (single– or multi–cycle) instruction, then halt. If the instruction is within a routine, execute the instruction and halt at the first instruction following the call.
Run to cursor [F4]
Executes all instructions between the current instruction and the cursor position.
Run to Cursor
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Toggle
Breakpoint.
making it simple...
Toggle Breakpoint [F5]
Toggle breakpoint at current cursor position. To view all the breakpoints, select
Run > View Breakpoints from the drop-down menu. Double clicking an item in
window list locates the breakpoint.
Watch Window
Variables
The Watch Window allows you to monitor program items while running your program. It displays variables and special function registers of PIC MCU, their
addresses and values. Values are updated as you go through the simulation.
Double clicking one of the items opens a window in which you can assign a new
value to the selected variable or register and change number formatting.
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Stopwatch Window
The Stopwatch Window displays the current count of cycles/time since the last
Debugger action. Stopwatch measures the execution time (number of cycles) from
the moment the Debugger is started, and can be reset at any time. Delta represents
the number of cycles between the previous instruction line (line where the
Debugger action was performed) and the active instruction line (where the
Debugger action landed).
Note: You can change the clock in the Stopwatch Window; this will recalculate
values for the newly specified frequency. Changing the clock in the Stopwatch
Window does not affect the actual project settings – it only provides a simulation.
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View RAM Window
Debugger View RAM Window is available from the drop-down menu, View ›
Debug Windows › View RAM.
The View RAM Window displays the map of PIC’s RAM, with recently changed
items colored red. You can change value of any field by double-clicking it.
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ERROR WINDOW
In case that errors were encountered during compiling, the compiler will report
them and won't generate a hex file. The Error Window will be prompted at the
bottom of the main window by default.
The Error Window is located under the message tab, and displays location and
type of errors compiler has encountered. The compiler also reports warnings, but
these do not affect the output; only errors can interefere with generation of hex.
Double click the message line in the Error Window to highlight the line where the
error was encountered.
Consult the Error Messages for more information about errors recognized by the
compiler.
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STATISTICS
Statistics Icon.
After successful compilation, you can review statistics of your code. Select Project
> View Statistics from the drop-down menu, or click the Statistics icon. There are
six tab windows:
Memory Usage Window
Provides overview of RAM and ROM memory usage in form of histogram.
Procedures (Graph) Window
Displays functions in form of histogram, according to their memory allotment.
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Procedures (Locations) Window
Displays how functions are distributed in microcontroller’s memory.
Procedures (Details) Window
Displays complete call tree, along with details for each function:
size, start and end address, calling frequency, return type, etc.
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RAM Window
Summarizes all GPR and SFR registers and their addresses. Also displays symbolic names of variables and their addresses.
ROM Window
Lists op-codes and their addresses in form of a human readable hex code.
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INTEGRATED TOOLS
USART Terminal
mikroC includes the USART (Universal Synchronous Asynchronous Receiver
Transmitter) communication terminal for RS232 communication. You can launch
it from the drop-down menu Tools > Terminal or by clicking the Terminal icon.
ASCII Chart
The ASCII Chart is a handy tool, particularly useful when working with LCD display. You can launch it from the drop-down menu Tools > ASCII chart.
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7 Segment Display Decoder
The 7seg Display Decoder is a convenient visual panel which returns decimal/hex
value for any viable combination you would like to display on 7seg. Click on the
parts of 7 segment image to get the desired value in the edit boxes. You can launch
it from the drop-down menu Tools > 7 Segment Display.
EEPROM Editor
EEPROM Editor allows you to easily manage EEPROM of PIC microcontroller.
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mikroBootloader
mikroBootloader can be used only with PICmicros that support flash write.
1. Load the PIC with the appropriate hex file using the conventional programming
techniques (e.g. for PIC16F877A use p16f877a.hex).
2. Start mikroBootloader from the drop-down menu Tools > Bootoader.
3. Click on Setup Port and select the COM port that will be used. Make sure that
BAUD is set to 9600 Kpbs.
4. Click on Open File and select the HEX file you would like to upload.
5. Since the bootcode in the PIC only gives the computer 4-5 sec to connect, you
should reset the PIC and then click on the Connect button within 4-5 seconds.
6. The last line in then history window should now read “Connected”.
7. To start the upload, just click on the Start Bootloader button.
8. Your program will written to the PIC flash. Bootloader will report an errors that
may occur.
9. Reset your PIC and start to execute.
The boot code gives the computer 5 seconds to get connected to it. If not, it starts
running the existing user code. If there is a new user code to be downloaded, the
boot code receives and writes the data into program memory.
The more common features a bootloader may have are listed below:
- Code at the Reset location.
- Code elsewhere in a small area of memory.
- Checks to see if the user wants new user code to be loaded.
- Starts execution of the user code if no new user code is to be loaded.
- Receives new user code via a communication channel if code is to be loaded.
- Programs the new user code into memory.
Integrating User Code and Boot Code
The boot code almost always uses the Reset location and some additional program
memory. It is a simple piece of code that does not need to use interrupts; therefore,
the user code can use the normal interrupt vector at 0x0004. The boot code must
avoid using the interrupt vector, so it should have a program branch in the address
range 0x0000 to 0x0003. The boot code must be programmed into memory using
conventional programming techniques, and the configuration bits must be programmed at this time. The boot code is unable to access the configuration bits,
since they are not mapped into the program memory space.
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KEYBOARD SHORTCUTS
Below is the complete list of keyboard shortcuts available in mikroC IDE. You can
also view keyboard shortcuts in Code Explorer window, tab Keyboard.
IDE Shortcuts
F1
CTRL+N
CTRL+O
CTRL+F9
CTRL+F11
CTRL+SHIFT+F5
Help
New Unit
Open
Compile
Code Explorer on/off
View breakpoints
Basic Editor shortcuts
F3
CTRL+A
CTRL+C
CTRL+F
CTRL+P
CTRL+R
CTRL+S
CTRL+SHIFT+S
CTRL+V
CTRL+X
CTRL+Y
CTRL+Z
Find, Find Next
Select All
Copy
Find
Print
Replace
Save unit
Save As
Paste
Cut
Redo
Undo
Advanced Editor shortcuts
CTRL+SPACE
CTRL+SHIFT+SPACE
CTRL+D
CTRL+G
CTRL+J
CTRL+<number>
CTRL+SHIFT+<number>
CTRL+SHIFT+I
CTRL+SHIFT+U
CTRL+ALT+SELECT
Code Assistant
Parameters Assistant
Find declaration
Goto line
Insert Code Template
Goto bookmark
Set bookmark
Indent selection
Unindent selection
Select columns
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Debugger Shortcuts
F4
F5
F6
F7
F8
F9
CTRL+F2
Run to Cursor
Toggle breakpoint
Run/Pause Debugger
Step into
Step over
Debug
Reset
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CHAPTER
2
Building
Applications
Creating applications in mikroC is easy and intuitive. Project Wizard allows you to
set up your project in just few clicks: name your application, select chip, set flags,
and get going.
mikroC allows you to distribute your projects in as many files as you find appropriate. You can then share your mikroCompiled Libraries (.mcl files) with other
developers without disclosing the source code. The best part is that you can use
.mcl bundles created by mikroPascal or mikroBasic!
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PROJECTS
mikroC organizes applications into projects, consisting of a single project file
(extension .ppc) and one or more source files (extension .c). You can compile
source files only if they are part of a project.
Project file carries the following information:
- project name and optional description,
- target device,
- device flags (config word) and device clock,
- list of project source files with paths.
New Project
New Project.
The easiest way to create project is by means of New Project Wizard, drop-down
menu Project > New Project. Just fill the dialog with desired values (project name
and description, location, device, clock, config word) and mikroC will create the
appropriate project file. Also, an empty source file named after the project will be
created by default.
Editing Project
Edit Project.
Later, you can change project settings from drop-down menu Project > Edit
Project. You can rename the project, modify its description, change chip, clock,
config word, etc. To delete a project, simply delete the folder in which the project
file is stored.
Add/Remove Files from Project
Add to Project.
Remove from
Project.
Project can contain any number of source files (extension .c). The list of relevant
source files is stored in the project file (extension .ppc). To add source file to
your project, select Project > Add to Project from drop-down menu. Each added
source file must be self-contained, i.e. it must have all the necessary definitions
after preprocessing. To remove file(s) from your project, select Project > Remove
from Project from drop-down menu.
Note: For inclusion of header files, use the preprocessor directive #include.
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Extended functionality of the Project Files tab
By using the Project Files' new features, you can reach all the output files (.lst,
.asm) by a single click. You can also include in project the library files (.mcl), for
libraries, either your own or compiler default, that are project-specific.
Libraries (.mcl) now have different, more compact format, compared to mikroC
version 2. This, however, means that library formats are now incompatible. The
users that are making transition from version 2 to 5, must re- build all their previously written libraries in order to use them in the new version. All the source code
written and tested in previous versions should compile correctly on version 5.0,
except for the asm{} blocks, which are commented in the asm section of help.
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SOURCE FILES
Source files containing C code should have the extension .c. List of source files
relevant for the application is stored in project file with extension .ppc, along
with other project information. You can compile source files only if they are part
of a project.
Use the preprocessor directive #include to include headers. Do not rely on preprocessor to include other source files — see Projects for more information.
Search Paths
Paths for source files (.c)
You can specify your own custom search paths. This can be configured by selecting Tools > Options from drop-down menu and then tab window Advanced.
In project settings, you can specify either absolute or relative path to the source
file. If you specify a relative path, mikroC will look for the file in following locations, in this particular order:
1. the project folder (folder which contains the project file .ppc),
2. your custom search paths,
3. mikroC installation folder > “uses” folder.
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Paths for Header Files (.h)
Header files are included by means of preprocessor directive #include. If you
place an explicit path to the header file in preprocessor directive, only that location
will be searched.
You can specify your own custom search paths: select Tools › Options from the
drop-down menu and then select Search Path.
In project settings, you can specify either absolute or relative path to the header. If
you specify a relative path, mikroC will look for the file in following locations, in
this particular order:
1. the project folder (folder which contains the project file .ppc),
2. mikroC installation folder > “include” folder,
3. your custom search paths.
Managing Source Files
Creating a new source file
New File.
To create a new source file, do the following:
Select File > New from drop-down menu, or press CTRL+N, or click the New
File icon. A new tab will open, named “Untitled1”. This is your new source file.
Select File > Save As from drop-down menu to name it the way you want.
If you have used New Project Wizard, an empty source file, named after the project with extension .c, is created automatically. mikroC does not require you to
have source file named same as the project, it’s just a matter of convenience.
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Opening an Existing File
Open File Icon.
Select File > Open from drop-down menu, or press CTRL+O, or click the Open
File icon. The Select Input File dialog opens. In the dialog, browse to the location
of the file you want to open and select it. Click the Open button.
The selected file is displayed in its own tab. If the selected file is already open, its
current Editor tab will become active.
Printing an Open File
Print File Icon.
Make sure that window containing the file you want to print is the active window.
Select File > Print from drop-down menu, or press CTRL+P, or click the Print
icon. In the Print Preview Window, set the desired layout of the document and
click the OK button. The file will be printed on the selected printer.
Saving File
Save File Icon.
Make sure that window containing the file you want to save is the active window.
Select File > Save from drop-down menu, or press CTRL+S, or click the Save
icon. The file will be saved under the name on its window.
Saving File Under a Different Name
Save File As.
Make sure that window containing the file you want to save is the active window.
Select File > Save As from drop-down menu, or press SHIFT+CTRL+S. The New
File Name dialog will be displayed. In the dialog, browse to the folder where you
want to save the file. In the File Name field, modify the name of the file you want
to save. Click the Save button.
Closing a File
Close File.
Make sure that tab containing the file you want to close is the active tab. Select
File > Close from drop-down menu, or right click the tab of the file you want to
close in Code Editor. If the file has been changed since it was last saved, you will
be prompted to save your changes.
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COMPILATION
Compile Icon.
When you have created the project and written the source code, you will want to
compile it. Select Project > Build from drop-down menu, or click Build Icon, or
simply hit CTRL+F9.
Progress bar will appear to inform you about the status of compiling. If there are
errors, you will be notified in the Error Window. If no errors are encountered,
mikroC will generate output files.
Output Files
Upon successful compilation, mikroC will generate output files in the project folder (folder which contains the project file .ppc). Output files are summarized
below:
Intel HEX file (.hex)
Intel style hex records. Use this file to program PIC MCU.
Binary mikro Compiled Library (.mcl)
Binary distribution of application that can be included in other projects.
List File (.lst)
Overview of PIC memory allotment: instruction addresses, registers, routines, etc.
Assembler File (.asm)
Human readable assembly with symbolic names, extracted from the List File.
Assembly View
View Assembly
Icon.
After compiling your program in mikroC, you can click View Assembly Icon or
select Project › View Assembly from drop-down menu to review generated assembly code (.asm file) in a new tab window. Assembly is human readable with symbolic names. All physical addresses and other information can be found in
Statistics or in list file (.lst).
If the program is not compiled and there is no assembly file, starting this option
will compile your code and then display assembly.
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ERROR MESSAGES
Error Messages
-
Specifier needed
Invalid declarator
Expected '(' or identifier
Integer const expected
Array dimension must be greater then 0
Local objects cannot be extern
Declarator error
Bad storage class
Arguments cannot be of void type
Specifer/qualifier list expected
Address must be greater than 0
Identifier redefined
case out of switch
default label out of switch
switch exp. must evaluate to integral type
continue outside of loop
break outside of loop or switch
void func cannot return values
Unreachable code
Illegal expression with void
Left operand must be pointer
Function required
Too many chars
Undefined struct
Nonexistent field
Aggregate init error
Incompatible types
Identifier redefined
Function definition not found
Signature does not match
Cannot generate code for expression
Too many initializers of subaggregate
Nonexistent subaggregate
Stack Overflow: func call in complex expression
Syntax Error: expected %s but %s found
Array element cannot be function
Function cannot return array
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Inconsistent storage class
Inconsistent type
%s tag redefined
Illegal typecast
%s is not a valid identifier
Invalid statement
Constant expression required
Internal error %s
Too many arguments
Not enough parameters
Invalid expresion
Identifier expected, but %s found
Operator [%s] not applicable to this operands [%s]
Assigning to non-lvalue [%s]
Cannot cast [%s] to [%s]
Cannot assign [%s] to [%s]
lvalue required
Pointer required
Argument is out of range
Undeclared identifier [%s] in expression
Too many initializers
Cannot establish this baud rate at %s MHz clock
Compiler Warning Messages
- Highly inefficent code: func call in complex expression
- Inefficent code: func call in complex expression
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CHAPTER
3
mikroC Language
Reference
C offers unmatched power and flexibility in programming microcontrollers.
mikroC adds even more power with an array of libraries, specialized for PIC HW
modules and communications. This chapter should help you learn or recollect C
syntax, along with the specifics of programming PIC microcontrollers. If you are
experienced in C programming, you will probably want to consult mikroC
Specifics first.
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PIC SPECIFICS
In order to get the most from your mikroC compiler, you should be familiar with
certain aspects of PIC MCU. This knowledge is not essential, but it can provide
you a better understanding of PICs’ capabilities and limitations, and their impact
on the code writing.
Types Efficiency
First of all, you should know that PIC’s ALU, which performs arithmetic operations, is optimized for working with bytes. Although mikroC is capable of handling very complex data types, PIC may choke on them, especially if you are
working on some of the older models. This can dramatically increase the time
needed for performing even simple operations. Universal advice is to use the
smallest possible type in every situation. It applies to all programming in general,
and doubly so with microcontrollers.
When it comes down to calculus, not all PICmicros are of equal performance. For
example, PIC16 family lacks hardware resources to multiply two bytes, so it is
compensated by a software algorithm. On the other hand, PIC18 family has HW
multiplier, and as a result, multiplication works considerably faster.
Nested Calls Limitations
Nested call represents a function call within function body, either to itself (recursive calls) or to another function. Recursive function calls are supported by
mikroC but with limitations. Recursive function calls can't contain any function
parameters and local variables due to the PIC’s stack and memory limitations.
mikroC limits the number of non-recursive nested calls to:
- 8 calls for PIC12 family,
- 8 calls for PIC16 family,
- 31 calls for PIC18 family.
Number of the allowed nested calls decreases by one if you use any of the following operators in the code: * / %. It further decreases if you use interrupts in the
program. Number of decreases is specified by number of functions called from
interrupt. Check functions reentrancy. If the allowed number of nested calls is
exceeded, the compiler will report a stack overflow error.
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PIC16 Specifics
Breaking Through Pages
In applications targeted at PIC16, no single routine should exceed one page (2,000
instructions). If routine does not fit within one page, linker will report an error.
When confront with this problem, maybe you should rethink the design of your
application – try breaking the particular routine into several chunks, etc.
Limits of Indirect Approach Through FSR
Pointers with PIC16 are “near”: they carry only the lower 8 bits of the address.
Compiler will automatically clear the 9th bit upon startup, so that pointers will
refer to banks 0 and 1. To access the objects in banks 3 or 4 via pointer, user
should manually set the IRP, and restore it to zero after the operation. The stated
rules apply to any indirect approach: arrays, structures and unions assignments,
etc.
Note: It is very important to take care of the IRP properly, if you plan to follow
this approach. If you find this method to be inappropriate with too many variables,
you might consider upgrading to PIC18.
Note: If you have many variables in the code, try rearranging them with linker
directive absolute. Variables that are approached only directly should be moved
to banks 3 and 4 for increased efficiency.
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mikroC SPECIFICS
ANSI Standard Issues
Divergence from the ANSI C Standard
mikroC diverges from the ANSI C standard in few areas. Some of these modifications are improvements intenteded to facilitate PIC programming, while others are
result of PICmicro hardware limitations:
Function recursion is supported with limitations because of no easily-usable stack
and limited memory. See PIC Specifics.
Pointers to variables and pointers to constants are not compatible, i.e. no assigning
or comparison is possible between the two.
mikroC treats identifiers declared with const qualifier as “true constants” (C++
style). This allows using const objects in places where ANSI C would expect a
constant expression. If aiming at portability, use the traditional preprocessor
defined constants. See Type Qualifiers and Constants.
mikroC allows C++ style single–line comments using two adjacent slashes (//).
Features under construction: anonymous structures and unions.
Implementation-defined Behavior
Certain sections of the ANSI standard have implementation-defined behavior. This
means that the exact behavior of some C code can vary from compiler to compiler.
Throughout the help are sections describing how the mikroC compiler behaves in
such situations. The most notable specifics include: Floating-point Types, Storage
Classes, and Bit Fields.
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Predefined Globals and Constants
To facilitate PIC programming, mikroC implements a number of predefined globals and constants.
All PIC SFR registers are implicitly declared as global variables of volatile
unsigned short. These identifiers have external linkage, and are visible in the
entire project. When creating a project, mikroC will include an appropriate .def
file, containing declarations of available SFR and constants (such as T0IE, INTF,
etc). Identifiers are all in uppercase, identical to nomenclature in Microchip
datasheets. For the complete set of predefined globals and constants, look for
“Defs” in your mikroC installation folder, or probe the Code Assistant for specific
letters (Ctrl+Space in Editor).
Accessing Individual Bits
mikroC allows you to access individual bits of 8-bit variables, types char and
unsigned short. Simply use the direct member selector (.) with a variable,
followed by one of identifiers F0, F1, … , F7. For example:
// If RB0 is set, set RC0:
if (PORTB.F0) PORTC.F0 = 1;
There is no need for any special declarations; this kind of selective access is an
intrinsic feature of mikroC and can be used anywhere in the code. Identifiers
F0–F7 are not case sensitive and have a specific namespace.
Provided you are familiar with the particular chip, you can also access bits by
name:
INTCON.TMR0F = 0;
// Clear TMR0F
See Predefined Globals and Constants for more information on register/bit names.
Note: If aiming at portability, avoid this style of accessing individual bits, and use
the bit fields instead.
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Interrupts
Interrupts can be easily handled by means of reserved word interrupt. mikroC
implictly declares function interrupt which cannot be redeclared. Its prototype is:
void interrupt(void);
Write your own definition (function body) to handle interrupts in your application.
mikroC saves the following SFR on stack when entering interrupt and pops them
back upon return:
PIC12 and PIC16 family: W, STATUS, FSR, PCLATH
PIC18 family: FSR (fast context is used to save WREG, STATUS, BSR)
Note: mikroC does not support low priority interrupts; for PIC18 family, interrupts
must be of high priority.
Function Calls from Interrupt
Calling functions from within the interrupt() routine is now possible. The compiler
takes care about the registers being used, both in "interrupt" and in "main" thread,
and performs "smart" context-switching between the two, saving only the registers
that have been used in both threads.Check functions reentrancy.
Here is a simple example of handling the interrupts from TMR0 (if no other
interrupts are allowed):
void interrupt() {
counter++;
TMR0 = 96;
INTCON = $20;
}//~
In case of multiple interrupts enabled, you need to test which of the interrupts
occurred and then proceed with the appropriate code (interrupt handling).
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Linker Directives
mikroC uses internal algorithm to distribute objects within memory. If you need to
have variable or routine at specific predefined address, use linker directives
absolute and org.
Directive absolute
Directive absolute specifies the starting address in RAM for variable. If variable is
multi-byte, higher bytes are stored at consecutive locations. Directive absolute is
appended to the declaration of variable:
int foo absolute 0x23;
// Variable will occupy 2 bytes at addresses 0x23 and 0x24;
Be careful when using absolute directive, as you may overlap two variables by
mistake. For example:
char i absolute 0x33;
// Variable i will occupy 1 byte at address 0x33
long jjjj absolute 0x30;
// Variable will occupy 4 bytes at 0x30, 0x31, 0x32, 0x33,
// so changing i changes jjjj highest byte at the same time
Directive org
Directive org specifies the starting address of routine in ROM.
Directive org is appended to the function definition. Directives applied to nondefining declarations will be ignored, with an appropriate warning issued by linker. Directive org cannot be applied to an interrupt routine.
Here is a simple example:
void func(char par) org 0x200 {
// Function will start at address 0x200
nop;
}
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Code Optimization
Optimizer has been added to extend the compiler usability, cuts down the amount
of code generated and speed-up its execution. Main features are:
Constant folding
All expressions that can be evaluated in the compile time (i.e. are constant) are
being replaced by their result. (3 + 5 -> 8);
Constant propagation
When a constant value is being assigned to certain variable, the compiler recognizes this and replaces the use of the variable in the code that follows by constant,
as long as variable's value remains unchanged.
Copy propagation
The compiler recognizes that two variables have same value and eliminates one of
them in the further code.
Value numbering
The compiler "recognize" if the two expressions yield the same result, and can
therefore eliminate the entire computation for one of them.
"Dead code" ellimination
The code snippets that are not being used elsewhere in the programme do not
affect the final result of the application. They are automatically being removed.
Stack allocation
Temporary registers ("Stacks") are being used more rationally, allowing for VERY
complex expressions to be evaluated with minimum stack consumption.
Local vars optimization
No local variables are being used if their result does not affect some of the global
or volatile variables.
Better code generation and local optimization
Code generation is more consistent, and much attention has been made to implement specific solutions for the code "building bricks" that further reduce output
code size.
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Indirect Function Calls
If the linker encounters an indirect function call (by a pointer to function), it
assumes that any one of the functions, addresses of which were taken anywhere in
the program, can be called at that point. Use the #pragma funcall directive to
instruct the linker which functions can be called indirectly from the current function:
#pragma funcall <func_name> <called_func>[, <called_func>,...]
A corresponding pragma must be placed in the source module where function
func_name is implemented. This module must also include declarations of all
functions listed in the called_func list.
Note: The #pragma funcall directive can help the linker to optimize function
frame allocation in the compiled stack.
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LEXICAL ELEMENTS
These topics provide a formal definition of the mikroC lexical elements. They
describe the different categories of word-like units (tokens) recognized by a language.
In the tokenizing phase of compilation, the source code file is parsed (that is, broken down) into tokens and whitespace. The tokens in mikroC are derived from a
series of operations performed on your programs by the compiler and its built-in
preprocessor.
A mikroC program starts as a sequence of ASCII characters representing the
source code, created by keystrokes using a suitable text editor (such as the mikroC
editor). The basic program unit in mikroC is the file. This usually corresponds to a
named file located in RAM or on disk and having the extension .c.
Whitespace
Whitespace is the collective name given to spaces (blanks), horizontal and vertical
tabs, newline characters, and comments. Whitespace can serve to indicate where
tokens start and end, but beyond this function, any surplus whitespace is discarded. For example, the two sequences
int i; float f;
and
int i;
float f;
are lexically equivalent and parse identically to give the six tokens.
The ASCII characters representing whitespace can occur within literal strings, in
which case they are protected from the normal parsing process (they remain as
part of the string).
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Comments
Comments are pieces of text used to annotate a program, and are technically
another form of whitespace. Comments are for the programmer’s use only; they
are stripped from the source text before parsing. There are two ways to delineate
comments: the C method and the C++ method. Both are supported by mikroC.
C comments
C comment is any sequence of characters placed after the symbol pair /*. The
comment terminates at the first occurrence of the pair */ following the initial /*.
The entire sequence, including the four comment-delimiter symbols, is replaced by
one space after macro expansion.
In mikroC,
int /* type */ i /* identifier */;
parses as:
int i;
Note that mikroC does not support the nonportable token pasting strategy using
/**/. For more on token pasting, refer to Preprocessor topics.
C++ comments
mikroC allows single-line comments using two adjacent slashes (//). The comment can start in any position, and extends until the next new line. The following
code,
int i;
int j;
// this is a comment
parses as:
int i;
int j;
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mikro ICD (In-Circuit Debugger)
mikro ICD is highly effective tool for Real-Time debugging on hardware level.
ICD debugger enables you to execute a mikroC program on a host PIC microcontroller and view variable values, Special Function Registers (SFR), memory and
EEPROM as the program is running.
If you have appropriate hardware and software for using mikro ICD then you have
to upon completion of writing your program to choose between Release build
Type or ICD Debug build type.
After you choose ICD Debug build type it's time to compile your project. After
you have successfully compiled your project you must program PIC using F11
shortcut. After successful PIC programming you have to select mikro ICD by
selecting Debugger › Select Debugger › mikro ICD Debugger from the dropdown menu.
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You can run the mikro ICD by selecting Run › Debug from the drop-down menu,
or by clicking Debug Icon . Starting the Debugger makes more options available:
Step Into, Step Over, Run to Cursor, etc. Line that is to be executed is color highlighted (blue by default). There is also notification about program execution and it
can be found on Watch Window (yellow status bar). Note that some functions take
time to execute, so running of program is indicated on Watch Window.
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mikro ICD Debugger Options
Name
Description
Function Key
Debug
Starts Debugger.
[F9]
Run/ Pause
Debugger
Run or pause Debugger.
[F6]
Toggle
Breakpoints
Toggle breakpoint at the current cursor position. To view all the breakpoints, select Run ›
View Breakpoints from the drop-down menu.
Double clicking an item in window list
locates the breakpoint.
[F5]
Run to cursor
Execute all instructions between the current
instruction and the cursor position.
[F4]
Step Into
Execute the current C (single– or
multi–cycle) instruction, then halt. If the
instruction is a routine call, enter the routine
and halt at the first instruction following the
call.
[F7]
Step Over
Execute the current C (single– or
multi–cycle) instruction, then halt. If the
instruction is a routine call, skip it and halt at
the first instruction following the call.
[F8]
Flush RAM
Flushes current PIC RAM. All variable values will be changed according to values from
watch window.
N/A
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mikro ICD Debugger Example
Here is a step by step mikro ICD Debugger Example. First you have to write a
program. We will show how mikro ICD works using this example:
void main(){
char text[21]="mikroElektronika";
char i=0;
PORTD = 0x00;
TRISD = 0x00;
Lcd_Init(&PORTD);
Lcd_Cmd(LCD_CLEAR);
Lcd_Cmd(LCD_CURSOR_OFF);
for(i=1;i<17;i++){
Lcd_Chr(1,i,text[i-1]);
}
}
After successful compilation and PIC programming press F9
for starting mikro ICD. After mikro ICD initialization blue active line should
appear.
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We will debug program line by line. Pressing F8 we are executing code line by
line. It is recommended that user does not use Step Into [F7] and Step Over [F8]
over Delays routines and routines containing delays. Instead use Run to cursor
[F4] and Breakpoints functions.
All changes are read from PIC and loaded into Watch Window. Note that TRISD
changed its value from 255 to 0.
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Step Into [F7] and Step Over [F8] are mikro ICD debugger functions that are used
in stepping mode. There is also Real-Time mode supported by mikro ICD.
Functions that are used in Real-Time mode are Run/ Pause Debugger [F6] and
Run to cursor [F4]. Pressing F4 goes to line selected by user. User just have to
select line with cursor and press F4, and code will be executed until selected line
is reached.
Run(Pause) Debugger [F6] and Toggle Breakpoints [F5] are mikro ICD debugger
functions that are used in Real-Time mode. Pressing F5 marks line selected by
user for breakpoint. F6 executes code until breakpoint is reached. After reaching
breakpoint Debugger halts. Here at our example we will use breakpoints for writing "mikroElektronika" on LCD char by char. Breakpoint is set on LCD_Chr and
program will stop everytime this function is reached. After reaching breakpoint we
must press F6 again for continuing program execution.
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Breakpoints has been separated into two groups. There are hardware and software
break points. Hardware breakpoints are placed in PIC and they provide fastest
debug. Number of hardware breakpoints is limited (1 for P16 and 1 or 3 for P18).
If all hardware brekpoints are used, next breakpoints that will be used are software
breakpoint. Those breakpoints are placed inside mikro ICD, and they simulate
hardware breakpoints. Software breakpoints are much slower than hardware breakpoints. This differences between hardware and software differences are not visible
in mikro ICD software but their different timings are quite notable, so it is important to know that there is two types of breakpoints.
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mikro ICD (In-Circuit Debugger) Overview
Watch Window
Debugger Watch Window is the main Debugger window which allows you to
monitor program items while running your program. To show the Watch Window,
select View › Debug Windows › Watch Window from the drop-down menu.
The Watch Window displays variables and registers of PIC, with their addresses
and values. Values are updated as you go through the simulation. Use the dropdown menu to add and remove the items that you want to monitor. Recently
changed items are colored red.
Double clicking an item opens the Edit Value window in which you can assign a
new value to the selected variable/register. Also, you can change view to binary,
hex, char, or decimal for the selected item.
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View EEPROM Window
mikro ICD EEPROM Window is available from the drop-down menu, View ›
Debug Windows › View EEPROM.
The EEPROM window shows current values written into PIC internal EEPROM
memory. There are two action buttons concerning EEPROM watch window Flush EEPROM and Read EEPROM. Flush EEPROM writes data from EEPROM window into PIC internal EEPROM memory. Read EEPROM reads data
from PIC internal EEPROM memory and loads it up in EEPROM window.
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View Code Window
mikro ICD View Code Window is available from the drop-down menu, View ›
Debug Windows › View Code.
The View Code window shows code (hex code) written into PIC. There is action
button concerning View Code watch window - Read Code. Read Code reads
code from PIC and loads it up in View Code Window.
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View RAM Window
Debugger View RAM Window is available from the drop-down menu, View ›
Debug Windows › View RAM.
The View RAM Window displays the map of PIC’s RAM, with recently changed
items colored red.
Common Errors
- Trying to program PIC while mikro ICD is active.
- Trying to debug Release build Type version of program.
- Trying to debug changed program code which hasn't been compiled and programmed into PIC.
- Trying to select line that is empty for Run to cursor [F4] and Toggle Breakpoints
[F5] functions.
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TOKENS
Token is the smallest element of a C program that is meaningful to the compiler.
The parser separates tokens from the input stream by creating the longest token
possible using the input characters in a left–to–right scan.
mikroC recognizes following kinds of tokens:
- keywords,
- identifiers,
- constants,
- operators,
- punctuators (also known as separators).
Token Extraction Example
Here is an example of token extraction. Let’s have the following code sequence:
inter =
a+++b;
First, note that inter would be parsed as a single identifier, rather than as the
keyword int followed by the identifier er.
The programmer who wrote the code might have intended to write
inter = a + (++b)
but it won’t work that way. The compiler would parse it as the following seven
tokens:
inter
=
a
++
+
b
;
//
//
//
//
//
//
//
identifier
assignment operator
identifier
postincrement operator
addition operator
identifier
semicolon separator
Note that +++ parses as ++ (the longest token possible) followed by +.
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CONSTANTS
Constants or literals are tokens representing fixed numeric or character values.
mikroC supports:
- integer constants,
- floating point constants,
- character constants,
- string constants (strings literals),
- enumeration constants.
The data type of a constant is deduced by the compiler using such clues as numeric value and the format used in the source code.
Integer Constants
Integer constants can be decimal (base 10), hexadecimal (base 16), binary (base
2), or octal (base 8). In the absence of any overriding suffixes, the data type of an
integer constant is derived from its value.
Long and Unsigned Suffixes
The suffix L (or l) attached to any constant forces the constant to be represented
as a long. Similarly, the suffix U (or u) forces the constant to be unsigned. You
can use both L and U suffixes on the same constant in any order or case: ul, Lu,
UL, etc.
In the absence of any suffix (U, u, L, or l), constant is assigned the “smallest” of
the following types that can accommodate its value: short, unsigned short,
int, unsigned int, long int, unsigned long int.
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Otherwise:
If the constant has a U or u suffix, its data type will be the first of the following
that can accommodate its value: unsigned short, unsigned int, unsigned
long int.
If the constant has an L or l suffix, its data type will be the first of the following
that can accommodate its value: long int, unsigned long int.
If the constant has both U and L suffixes, (ul, lu, Ul, lU, uL, Lu, LU, or UL), its
data type will be unsigned long int.
Decimal Constants
Decimal constants from -2147483648 to 4294967295 are allowed. Constants
exceeding these bounds will produce an “Out of range” error. Decimal constants
must not use an initial zero. An integer constant that has an initial zero is interpreted as an octal constant.
In the absence of any overriding suffixes, the data type of a decimal constant is
derived from its value, as shown below:
< -2147483648
-2147483648 .. -32769
-32768 .. -129
-128 .. 127
128 .. 255
256 .. 32767
32768 .. 65535
65536 .. 2147483647
2147483648 .. 4294967295
> 4294967295
Error: Out of range!
long
int
short
unsigned short
int
unsigned int
long
unsigned long
Error: Out of range!
Hexadecimal Constants
All constants starting with 0x (or 0X) are taken to be hexadecimal. In the absence
of any overriding suffixes, the data type of an hexadecimal constant is derived
from its value, according to the rules presented above. For example, 0xC367 will
be treated as unsigned int.
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Binary Constants
All constants starting with 0b (or 0B) are taken to be binary. In the absence of any
overriding suffixes, the data type of an binary constant is derived from its value,
according to the rules presented above. For example, 0b11101 will be treated as
short.
Octal Constants
All constants with an initial zero are taken to be octal. If an octal constant contains
the illegal digits 8 or 9, an error is reported. In the absence of any overriding suffixes, the data type of an octal constant is derived from its value, according to the
rules presented above. For example, 0777 will be treated as int.
Floating Point Constants
A floating-point constant consists of:
- Decimal integer,
- Decimal point,
- Decimal fraction,
- e or E and a signed integer exponent (optional),
- Type suffix: f or F or l or L (optional).
You can omit either the decimal integer or the decimal fraction (but not both). You
can omit either the decimal point or the letter e (or E) and the signed integer exponent (but not both). These rules allow for conventional and scientific (exponent)
notations.
Negative floating constants are taken as positive constants with the unary operator
minus (-) prefixed.
mikroC limits floating-point constants to range
±1.17549435082E38 .. ±6.80564774407E38.
mikroC floating-point constants are of type double. Note that mikroC’s implementation of ANSI Standard considers float and double (together with the
long double variant) to be the same type.
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Character Constants
A character constant is one or more characters enclosed in single quotes, such as
'A', '+', or '\n'. In C, single-character constants have data type int. Multicharacter constants are referred to as string constants or string literals. For more
information refer to String Constants.
Escape Sequences
The backslash character (\) is used to introduce an escape sequence, which allows
the visual representation of certain nongraphic characters. One of the most common escape constants is the newline character (\n).
A backslash is used with octal or hexadecimal numbers to represent the ASCII
symbol or control code corresponding to that value; for example, '\x3F' for the
question mark. You can use any string of up to three octal or any number of hexadecimal numbers in an escape sequence, provided that the value is within legal
range for data type char (0 to 0xFF for mikroC). Larger numbers will generate the
compiler error “Numeric constant too large”.
For example, the octal number \777 is larger than the maximum value allowed
(\377) and will generate an error. The first nonoctal or nonhexadecimal character
encountered in an octal or hexadecimal escape sequence marks the end of the
sequence.
Note: You must use \\ to represent an ASCII backslash, as used in operating system paths.
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The following table shows the available escape sequences in mikroC:
Sequence
Value
Char
What it does
\a
0x07
BEL
Audible bell
\b
0x08
BS
Backspace
\f
0x0C
FF
Formfeed
\n
0x0A
LF
Newline (Linefeed)
\r
0x0D
CR
Carriage Return
\t
0x09
HT
Tab (horizontal)
\v
0x0B
VT
Vertical Tab
\\
0x5C
\
Backslash
\'
0x27
'
Single quote
(Apostrophe)
\"
0x22
"
Double quote
\?
0x3F
?
Question mark
\O
any
O = string of up to 3
octal digits
\xH
any
H = string of hex digits
\XH
any
H = string of hex digits
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String Constants
String constants, also known as string literals, are a special type of constants
which store fixed sequences of characters. A string literal is a sequence of any
number of characters surrounded by double quotes:
"This is a string."
The null string, or empty string, is written like "". A literal string is stored internally as the given sequence of characters plus a final null character. A null string is
stored as a single null character.
The characters inside the double quotes can include escape sequences, e.g.
"\t\"Name\"\\\tAddress\n\n"
Adjacent string literals separated only by whitespace are concatenated during the
parsing phase. For example:
"This is " "just"
" an example."
is an equivalent to
"This is just an example."
Line continuation with backslash
You can also use the backslash (\) as a continuation character to extend a string
constant across line boundaries:
"This is really \
a one-line string."
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Enumeration Constants
Enumeration constants are identifiers defined in enum type declarations. The identifiers are usually chosen as mnemonics to assist legibility. Enumeration constants
are of int type. They can be used in any expression where integer constants are
valid.
For example:
enum weekdays {SUN = 0, MON, TUE, WED, THU, FRI, SAT};
The identifiers (enumerators) used must be unique within the scope of the enum
declaration. Negative initializers are allowed. See Enumerations for details of
enum declarations.
Pointer Constants
A pointer or the pointed-at object can be declared with the const modifier.
Anything declared as a const cannot be have its value changed. It is also illegal
to create a pointer that might violate the nonassignability of a constant object.
Constant Expressions
A constant expression is an expression that always evaluates to a constant and
consists only of constants (literals) or symbolic constants. It is evaluated at compile-time and it must evaluate to a constant that is in the range of representable
values for its type. Constant expressions are evaluated just as regular expressions
are.
Constant expressions can consist only of the following: literals, enumeration constants, simple constants (no constant arrays or structures), sizeof operators.
Constant expressions cannot contain any of the following operators, unless the
operators are contained within the operand of a sizeof operator: assignment,
comma, decrement, function call, increment.
You can use a constant expression anywhere that a constant is legal.
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KEYWORDS
Keywords are words reserved for special purposes and must not be used as normal
identifier names.
Beside standard C keywords, all relevant SFR are defined as global variables and
represent reserved words that cannot be redefined (for example: TMR0, PCL, etc).
Probe the Code Assistant for specific letters (Ctrl+Space in Editor) or refer to
Predefined Globals and Constants.
Here is the alphabetical listing of keywords in C:
asm
auto
break
case
char
const
continue
default
do
double
else
enum
extern
float
for
goto
if
int
long
register
return
short
signed
sizeof
static
struct
switch
typedef
union
unsigned
void
volatile
while
Also, mikroC includes a number of predefined identifiers used in libraries. You
could replace these by your own definitions, if you plan to develop your own
libraries. For more information, see mikroC Libraries.
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IDENTIFIERS
Identifiers are arbitrary names of any length given to functions, variables, symbolic constants, user-defined data types, and labels. All these program elements will
be referred to as objects throughout the help (not to be confused with the meaning
of object in object-oriented programming).
Identifiers can contain the letters a to z and A to Z, the underscore character “_”,
and the digits 0 to 9. The only restriction is that the first character must be a letter
or an underscore.
Case Sensitivity
mikroC identifiers are not case sensitive at present, so that Sum, sum, and suM represent an equivalent identifier. However, future versions of mikroC will offer the
option of activating/suspending case sensitivity. The only exceptions at present are
the reserved words main and interrupt which must be written in lowercase.
Uniqueness and Scope
Although identifier names are arbitrary (within the rules stated), errors result if the
same name is used for more than one identifier within the same scope and sharing
the same name space. Duplicate names are legal for different name spaces regardless of scope rules. For more information on scope, refer to Scope and Visibility.
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PUNCTUATORS
The mikroC punctuators (also known as separators) include brackets, parentheses,
braces, comma, semicolon, colon, asterisk, equal sign, and pound sign. Most of
these punctuators also function as operators.
Brackets
Brackets [ ] indicate single and multidimensional array subscripts:
char ch, str[] = "mikro";
int mat[3][4];
ch = str[3];
/* 3 x 4 matrix */
/* 4th element */
Parentheses
Parentheses ( ) are used to group expressions, isolate conditional expressions,
and indicate function calls and function parameters:
d = c * (a + b);
if (d == z) ++x;
func();
void func2(int n);
/*
/*
/*
/*
override normal precedence */
essential with conditional statement */
function call, no args */
function declaration with parameters */
Parentheses are recommended in macro definitions to avoid potential precedence
problems during expansion:
#define CUBE(x) ((x)*(x)*(x))
For more information, refer to Expressions and Operators Precedence.
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Braces
Braces { } indicate the start and end of a compound statement:
if (d == z) {
++x;
func();
}
The closing brace serves as a terminator for the compound statement, so a semicolon is not required after the }, except in structure declarations. Often, the semicolon is illegal, as in
if (statement)
{ ... };
else
{ ... };
/* illegal semicolon! */
For more information, refer to Compound Statements.
Comma
The comma (,) separates the elements of a function argument list:
void func(int n, float f, char ch);
The comma is also used as an operator in comma expressions. Mixing the two
uses of comma is legal, but you must use parentheses to distinguish them. Note
that (exp1, exp2) evalutates both but is equal to the second:
/* call func with two args */
func(i, j);
/* also calls func with two args! */
func((exp1, exp2), (exp3, exp4, exp5));
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Semicolon
The semicolon (;) is a statement terminator. Any legal C expression (including the
empty expression) followed by a semicolon is interpreted as a statement, known as
an expression statement. The expression is evaluated and its value is discarded. If
the expression statement has no side effects, mikroC might ignore it.
a + b;
++a;
;
/* evaluate a + b, but discard value */
/* side effect on a, but discard value of ++a */
/* empty expression or a null statement */
Semicolons are sometimes used to create an empty statement:
for (i = 0; i < n; i++) ;
For more information, see Statements.
Colon
Use the colon (:) to indicate a labeled statement. For example:
start: x = 0;
...
goto start;
Labels are discussed in Labeled Statements.
Asterisk (Pointer Declaration)
The asterisk (*) in a declaration denotes the creation of a pointer to a type:
char *char_ptr;
/* a pointer to char is declared */
You can also use the asterisk as an operator to either dereference a pointer or as
the multiplication operator:
i = *char_ptr;
For more information, see Pointers.
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Equal Sign
The equal sign (=) separates variable declarations from initialization lists:
int test[5] = {1, 2, 3, 4, 5};
int x = 5;
The equal sign is also used as the assignment operator in expressions:
int a, b, c;
a = b + c;
For more information, see Assignment Operators.
Pound Sign (Preprocessor Directive)
The pound sign (#) indicates a preprocessor directive when it occurs as the first
nonwhitespace character on a line. It signifies a compiler action, not necessarily
associated with code generation. See Preprocessor Directives for more information.
# and ## are also used as operators to perform token replacement and merging
during the preprocessor scanning phase. See Preprocessor Operators.
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OBJECTS AND LVALUES
Objects
An object is a specific region of memory that can hold a fixed or variable value
(or set of values). To prevent confusion, this use of the word object is different
from the more general term used in object-oriented languages. Our definiton of the
word would encompass functions, variables, symbolic constants, user-defined data
types, and labels.
Each value has an associated name and type (also known as a data type). The
name is used to access the object. This name can be a simple identifier, or it can
be a complex expression that uniquely references the object.
Objects and Declarations
Declarations establish the necessary mapping between identifiers and objects.
Each declaration associates an identifier with a data type.
Associating identifiers with objects requires each identifier to have at least two
attributes: storage class and type (sometimes referred to as data type). The mikroC
compiler deduces these attributes from implicit or explicit declarations in the
source code. Commonly, only the type is explicitly specified and the storage class
specifier assumes automatic value auto.
Generally speaking, an identifier cannot be legally used in a program before its
declaration point in the source code. Legal exceptions to this rule (known as forward references) are labels, calls to undeclared functions, and struct or union tags.
The range of objects that can be declared includes:
variables; functions; types; arrays of other types; structure, union, and enumeration
tags; structure members; union members; enumeration constants; statement labels;
preprocessor macros.
The recursive nature of the declarator syntax allows complex declarators. You’ll
probably want to use typedefs to improve legibility if constructing complex
objects.
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Lvalues
An lvalue is an object locator: an expression that designates an object. An example
of an lvalue expression is *P, where P is any expression evaluating to a non-null
pointer. A modifiable lvalue is an identifier or expression that relates to an object
that can be accessed and legally changed in memory. A const pointer to a constant,
for example, is not a modifiable lvalue. A pointer to a constant can be changed
(but its dereferenced value cannot).
Historically, the l stood for “left”, meaning that an lvalue could legally stand on
the left (the receiving end) of an assignment statement. Now only modifiable lvalues can legally stand to the left of an assignment operator. For example, if a and b
are nonconstant integer identifiers with properly allocated memory storage, they
are both modifiable lvalues, and assignments such as a = 1 and b = a + b are
legal.
Rvalues
The expression a + b is not an lvalue: a + b = a is illegal because the expression on the left is not related to an object. Such expressions are sometimes called
rvalues (short for right values).
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SCOPE AND VISIBILITY
Scope
The scope of identifier is the part of the program in which the identifier can be
used to access its object. There are different categories of scope: block (or local),
function, function prototype, and file. These depend on how and where identifiers
are declared.
Block Scope
The scope of an identifier with block (or local) scope starts at the declaration point
and ends at the end of the block containing the declaration (such a block is known
as the enclosing block). Parameter declarations with a function definition also
have block scope, limited to the scope of the function body.
File Scope
File scope identifiers, also known as globals, are declared outside of all blocks;
their scope is from the point of declaration to the end of the source file.
Function Scope
The only identifiers having function scope are statement labels. Label names can
be used with goto statements anywhere in the function in which the label is
declared. Labels are declared implicitly by writing label_name: followed by a
statement. Label names must be unique within a function.
Function Prototype Scope
Identifiers declared within the list of parameter declarations in a function prototype (not part of a function definition) have function prototype scope. This scope
ends at the end of the function prototype.
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Visibility
The visibility of an identifier is that region of the program source code from which
legal access can be made to the identifier’s associated object.
Scope and visibility usually coincide, though there are circumstances under which
an object becomes temporarily hidden by the appearance of a duplicate identifier:
the object still exists but the original identifier cannot be used to access it until the
scope of the duplicate identifier is ended.
Technically, visibility cannot exceed scope, but scope can exceed visibility. Take a
look at the following example:
void f (int i) {
int j;
j = 3;
{
double j;
j = 0.1;
// auto by default
// int i and j are in scope and visible
//
//
//
//
nested block
j is local name in the nested block
i and double j are visible;
int j = 3 in scope but hidden
}
j += 1;
// double j out of scope
// int j visible and = 4
}
// i and j are both out of scope
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NAME SPACES
Name space is the scope within which an identifier must be unique. C uses four
distinct categories of identifiers:
Goto label names
These must be unique within the function in which they are declared.
Structure, union, and enumeration tags
These must be unique within the block in which they are defined. Tags declared
outside of any function must be unique.
Structure and union member names
These must be unique within the structure or union in which they are defined.
There is no restriction on the type or offset of members with the same member
name in different structures.
Variables, typedefs, functions, and enumeration members
These must be unique within the scope in which they are defined. Externally
declared identifiers must be unique among externally declared variables.
Duplicate names are legal for different name spaces regardless of scope rules.
For example:
int blue = 73;
{ // open a block
enum colors { black, red, green, blue, violet, white } c;
/* enumerator blue hides outer declaration of int blue */
struct colors { int i, j; };
// ILLEGAL: colors duplicate tag
double red = 2;
// ILLEGAL: redefinition of red
}
blue = 37;
// back in int blue scope
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DURATION
Duration, closely related to storage class, defines the period during which the
declared identifiers have real, physical objects allocated in memory. We also distinguish between compile-time and run-time objects. Variables, for instance, unlike
typedefs and types, have real memory allocated during run time. There are two
kinds of duration: static and local.
Static Duration
Memory is allocated to objects with static duration as soon as execution is underway; this storage allocation lasts until the program terminates. Static duration
objects usually reside in fixed data segments allocated according to the memory
model in force. All globals have static duration. All functions, wherever defined,
are objects with static duration. Other variables can be given static duration by
using the explicit static or extern storage class specifiers.
In mikroC, static duration objects are not initialized to zero (or null) in the absence
of any explicit initializer.
An object can have static duration and local scope – see the example on the following page.
Local Duration
Local duration objects are also known as automatic objects. They are created on
the stack (or in a register) when the enclosing block or function is entered. They
are deallocated when the program exits that block or function. Local duration
objects must be explicitly initialized; otherwise, their contents are unpredictable.
The storage class specifier auto can be used when declaring local duration variables, but is usually redundant, because auto is the default for variables declared
within a block.
An object with local duration also has local scope, because it does not exist outside of its enclosing block. The converse is not true: a local scope object can have
static duration.
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Here is an example of two objects with local scope, but with different duration:
void f() {
/* local duration var; init a upon every call to f */
int a = 1;
/* static duration var; init b only upon 1st call to f */
static int b = 1;
/* checkpoint! */
a++;
b++;
}
void main() {
/* At checkpoint, we will
f();
// a=1, b=1, after
f();
// a=1, b=2, after
f();
// a=1, b=3, after
// etc.
}
have: */
first call,
second call,
third call,
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TYPES
C is strictly typed language, which means that every object, function, and expression need to have a strictly defined type, known in the time of compilation. Note
that C works exclusively with numeric types.
The type serves:
- to determine the correct memory allocation required initially,
- to interpret the bit patterns found in the object during subsequent accesses,
- in many type-checking situations, to ensure that illegal assignments are trapped.
mikroC supports many standard (predefined) and user-defined data types, including signed and unsigned integers in various sizes, floating-point numbers in various precisions, arrays, structures, and unions. In addition, pointers to most of these
objects can be established and manipulated in memory.
The type determines how much memory is allocated to an object and how the program will interpret the bit patterns found in the object’s storage allocation. A given
data type can be viewed as a set of values (often implementation-dependent) that
identifiers of that type can assume, together with a set of operations allowed on
those values. The compile-time operator, sizeof, lets you determine the size in
bytes of any standard or user-defined type.
The mikroC standard libraries and your own program and header files must provide unambiguous identifiers (or expressions derived from them) and types so that
mikroC can consistently access, interpret, and (possibly) change the bit patterns in
memory corresponding to each active object in your program.
Type Categories
The fudamental types represent types that cannot be separated into smaller parts.
They are sometimes referred to as unstructured types. The fundamental types are
void, char, int, float, and double, together with short, long, signed, and
unsigned variants of some of these.
The derived types are also known as structured types. The derived types include
pointers to other types, arrays of other types, function types, structures, and
unions.
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FUNDAMENTAL TYPES
Arithmetic Types
The arithmetic type specifiers are built from the following keywords: void, char,
int, float, and double, together with prefixes short, long, signed, and
unsigned. From these keywords you can build the integral and floating-point
types. Overview of types is given on the following page.
Integral Types
Types char and int, together with their variants, are considered integral data
types. Variants are created by using one of the prefix modifiers short, long,
signed, and unsigned.
The table below is the overview of the integral types – keywords in parentheses
can be (and often are) omitted.
The modifiers signed and unsigned can be applied to both char and int. In
the absence of unsigned prefix, signed is automatically assumed for integral types.
The only exception is the char, which is unsigned by default. The keywords
signed and unsigned, when used on their own, mean signed int and
unsigned int, respectively.
The modifiers short and long can be applied only to the int. The keywords
short and long used on their own mean short int and long int, respectively.
Floating-point Types
Types float and double, together with the long double variant, are considered floating-point types. mikroC’s implementation of ANSI Standard considers all
three to be the same type.
Floating point in mikroC is implemented using the Microchip AN575 32-bit format (IEEE 754 compliant).
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Below is the overview of arithmetic types:
Type
Size
Range
(unsigned) char
8-bit
0 .. 255
signed char
8-bit
- 128 .. 127
(signed) short (int)
8-bit
- 128 .. 127
unsigned short (int)
8-bit
0 .. 255
(signed) int
16-bit
-32768 .. 32767
unsigned (int)
16-bit
0 .. 65535
(signed) long (int)
32-bit
-2147483648 .. 2147483647
unsigned long (int)
32-bit
0 .. 4294967295
float
32-bit
±1.17549435082E-38 ..
±6.80564774407E38
double
32-bit
±1.17549435082E-38 ..
±6.80564774407E38
long double
32-bit
±1.17549435082E-38 ..
±6.80564774407E38
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Enumerations
An enumeration data type is used for representing an abstract, discreet set of values with appropriate symbolic names.
Enumeration Declaration
Enumeration is declared like this:
enum tag {enumeration-list};
Here, tag is an optional name of the enumeration; enumeration-list is a list
of discreet values, enumerators. The enumerators listed inside the braces are also
known as enumeration constants. Each is assigned a fixed integral value. In the
absence of explicit initializers, the first enumerator is set to zero, and each succeeding enumerator is set to one more than its predecessor.
Variables of enum type are declared same as variables of any other type. For
example, the following declaration
enum colors {black, red, green, blue, violet, white} c;
establishes a unique integral type, colors, a variable c of this type, and a set of
enumerators with constant integer values (black = 0, red = 1, ...). In C, a
variable of an enumerated type can be assigned any value of type int – no type
checking beyond that is enforced. That is:
c = red;
c = 1;
// OK
// Also OK, means the same
With explicit integral initializers, you can set one or more enumerators to specific
values. The initializer can be any expression yielding a positive or negative integer
value (after possible integer promotions). Any subsequent names without initializers will then increase by one. These values are usually unique, but duplicates are
legal.
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The order of constants can be explicitly re-arranged. For example:
enum colors { black,
red,
green,
blue=6,
violet,
white=4 };
//
//
//
//
//
//
value
value
value
value
value
value
0
1
2
6
7
4
Initializer expression can include previously declared enumerators. For example,
in the following declaration:
enum memory_sizes { bit = 1, nibble = 4 * bit,
byte = 2 * nibble, kilobyte = 1024 * byte };
nibble would acquire the value 4, byte the value 8, and kilobyte the value
8192.
Anonymous Enum Type
In our previous declaration, the identifier colors is the optional enumeration tag
that can be used in subsequent declarations of enumeration variables of type
colors:
enum colors bg, border;
// declare variables bg and border
As with struct and union declarations, you can omit the tag if no further variables
of this enum type are required:
/* Anonymous enum type: */
enum {black, red, green, blue, violet, white} color;
Enumeration Scope
Enumeration tags share the same name space as structure and union tags.
Enumerators share the same name space as ordinary variable identifiers. For more
information, consult Name Spaces.
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Void Type
void is a special type indicating the absence of any value. There are no objects of
void; instead, void is used for deriving more complex types.
Void Functions
Use the void keyword as a function return type if the function does not return a
value. For example:
void print_temp(char temp) {
Lcd_Out_Cp("Temperature:");
Lcd_Out_Cp(temp);
Lcd_Chr_Cp(223); // degree character
Lcd_Chr_Cp('C');
}
Use void as a function heading if the function does not take any parameters.
Alternatively, you can just write empty parentheses:
main(void) { // same as main()
...
}
Generic Pointers
Pointers can be declared as void, meaning that they can point to any type. These
pointers are sometimes called generic.
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DERIVED TYPES
The derived types are also known as structured types. These types are used as elements in creating more complex user-defined types.
Arrays
Array is the simplest and most commonly used structured type. Variable of array
type is actually an array of objects of the same type. These objects represent elements of an array and are identified by their position in array. An array consists of
a contiguous region of storage exactly large enough to hold all of its elements.
Array Declaration
Array declaration is similar to variable declaration, with the brackets added after
identifer:
type array_name[constant-expression]
This declares an array named as array_name composed of elements of type.
The type can be scalar type (except void), user-defined type, pointer, enumeration, or another array. Result of the constant-expression within the brackets
determines the number of elements in array. If an expression is given in an array
declarator, it must evaluate to a positive constant integer. The value is the number
of elements in the array.
Each of the elements of an array is numbered from 0 through the number of elements minus one. If the number is n, elements of array can be approached as
variables array_name[0] .. array_name[n-1] of type.
Here are a few examples of array declaration:
#define MAX = 50
int vector_one[10];
float vector_two[MAX];
float vector_three[MAX - 20];
/* an array of 10 integers */
/* an array of 50 floats
*/
/* an array of 30 floats
*/
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Array Initialization
Array can be initialized in declaration by assigning it a comma-delimited sequence
of values within braces. When initializing an array in declaration, you can omit the
number of elements – it will be automatically determined acording to the number
of elements assigned. For example:
/* An array which holds number of days in each month: */
int days[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
/* This declaration is identical to the previous one */
int days[] = {31,28,31,30,31,30,31,31,30,31,30,31};
If you specify both the length and starting values, the number of starting values
must not exceed the specified length. Vice versa is possible, when the trailing
“excess” elements will be assigned some encountered runtime values from memory.
In case of array of char, you can use a shorter string literal notation. For example:
/* The two declarations are identical: */
const char msg1[] = {'T', 'e', 's', 't', '\0'};
const char msg2[] = "Test";
For more information on string literals, refer to String Constants.
Arrays in Expressions
When name of the array comes up in expression evaluation (except with operators
& and sizeof ), it is implicitly converted to the pointer pointing to array’s first
element. See Arrays and Pointers for more information.
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Multi-dimensional Arrays
An array is one-dimensional if it is of scalar type. One-dimensional arrays are
sometimes referred to as vectors.
Multidimensional arrays are constructed by declaring arrays of array type. These
arrays are stored in memory in such way that the right most subscript changes
fastest, i.e. arrays are stored “in rows”. Here is a sample 2-dimensional array:
float m[50][20];
/* 2-dimensional array of size 50x20 */
Variable m is an array of 50 elements, which in turn are arrays of 20 floats each.
Thus, we have a matrix of 50x20 elements: the first element is m[0][0], the last
one is m[49][19]. First element of the 5th row would be m[0][5].
If you are not initializing the array in the declaration, you can omit the first dimension of multi-dimensional array. In that case, array is located elsewhere, e.g. in
another file. This is a commonly used technique when passing arrays as function
parameters:
int a[3][2][4];
/* 3-dimensional array of size 3x2x4 */
void func(int n[][2][4]) { /* we can omit first dimension */
//...
n[2][1][3]++; /* increment the last element*/
}//~
void main() {
//...
func(a);
}//~!
You can initialize a multi-dimensional array with an appropriate set of values
within braces. For example:
int a[3][2] = {{1,2}, {2,6}, {3,7}};
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Pointers
Pointers are special objects for holding (or “pointing to”) memory addresses. In C,
address of an object in memory can be obtained by means of unary operator &. To
reach the pointed object, we use indirection operator (*) on a pointer.
A pointer of type “pointer to object of type” holds the address of (that is, points to)
an object of type. Since pointers are objects, you can have a pointer pointing to a
pointer (and so on). Other objects commonly pointed at include arrays, structures,
and unions.
A pointer to a function is best thought of as an address, usually in a code segment,
where that function’s executable code is stored; that is, the address to which control is transferred when that function is called.
Although pointers contain numbers with most of the characteristics of unsigned
integers, they have their own rules and restrictions for declarations, assignments,
conversions, and arithmetic. The examples in the next few sections illustrate these
rules and restrictions.
Note: Currently, mikroC does not support pointers to functions, but this feature
will be implemented in future versions.
Pointer Declarations
Pointers are declared same as any other variable, but with * ahead of identifier.
Type at the beginning of declaration specifies the type of a pointed object. A pointer must be declared as pointing to some particular type, even if that type is void,
which really means a pointer to anything. Pointers to void are often called generic pointers, and are treated as pointers to char in mikroC.
If type is any predefined or user-defined type, including void, the declaration
type *p;
/* Uninitialized pointer */
declares p to be of type “pointer to type”. All the scoping, duration, and visibility
rules apply to the p object just declared. You can view the declaration in this way:
if *p is an object of type, then p has to be a pointer to such objects.
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Note: You must initialize pointers before using them! Our previously declared
pointer *p is not initialized (i.e. assigned a value), so it cannot be used yet.
Note: In case of multiple pointer declarations, each identifier requires an indirect
operator. For example:
int *pa, *pb, *pc;
/* is same as: */
int *pa;
int *pb;
int *pc;
Once declared, though, a pointer can usually be reassigned so that it points to an
object of another type. mikroC lets you reassign pointers without typecasting, but
the compiler will warn you unless the pointer was originally declared to be pointing to void. You can assign a void pointer to a non-void pointer – refer to Void
Type for details.
Null Pointers
A null pointer value is an address that is guaranteed to be different from any valid
pointer in use in a program. Assigning the integer constant 0 to a pointer assigns a
null pointer value to it. Instead of zero, the mnemonic NULL (defined in the standard library header files, such as stdio.h) can be used for legibility. All pointers
can be successfully tested for equality or inequality to NULL.
For example:
int *pn = 0; /* Here's one null pointer */
int *pn = NULL;
/* This is an equivalent declaration */
/* We can test the pointer like this: */
if ( pn == 0 ) { ... }
/* .. or like this: */
if ( pn == NULL ) { ... }
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Function Pointers
Function Pointers are pointers, i.e. variables, which point to the address of a function.
// Define a function pointer
int (*pt2Function) (float, char, char);
Note: Thus functions and function pointers with different calling convention
(argument order, arguments type or return type is different) are incompatible with
each other. Check Indirect Function Calls.
Assign an address to a Function Pointer
It's quite easy to assign the address of a function to a function pointer. You simply
take the name of a suitable and known function or member function. It's optional
to use the address operator & infront of the function's name.
//Assign an address to the function pointer
int DoIt (float a, char b, char c){ return a+b+c; }
pt2Function = &DoIt; // assignment
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Example:
int addC(char x,char y){
return x+y;
}
int subC(char x,char y){
return x-y;
}
int mulC(char x,char y){
return x*y;
}
int divC(char x,char y){
return x/y;
}
int modC(char x,char y){
return x%y;
}
//array of pointer to functions that receive two chars and returns
int
int
(*arrpf[])(char,char) = { addC ,subC,mulC,divC,modC};
int res;
char i;
void main() {
for (i=0;i<5;i++){
res = arrpf[i](10,20);
}
}//~!
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Pointer Arithmetic
Pointer arithmetic in C is limited to:
- assigning one pointer to another,
- comparing two pointers,
- comparing pointer to zero (NULL),
- adding/subtracting pointer and an integer value,
- subtracting two pointers.
The internal arithmetic performed on pointers depends on the memory model in
force and the presence of any overriding pointer modifiers. When performing
arithmetic with pointers, it is assumed that the pointer points to an array of
objects.
Arrays and Pointers
Arrays and pointers are not completely independent types in C. When name of the
array comes up in expression evaluation (except with operators & and sizeof ), it
is implicitly converted to the pointer pointing to array’s first element. Due to this
fact, arrays are not modifiable lvalues.
Brackets [ ] indicate array subscripts. The expression
id[exp]
is defined as
*((id) + (exp))
where either:
id is a pointer and exp is an integer, or
id is an integer and exp is a pointer.
The following is true:
&a[i]
a[i]
=
=
a + i
*(a + i)
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According to these guidelines, we can write:
pa = &a[4];
x = *(pa + 3);
y = *pa + 3;
// pa points to a[4]
// x = a[7]
// y = a[4] + 3
Also, you need to be careful with operator precedence:
*pa++;
(*pa)++;
// is equal to *(pa++), increments the pointer!
// increments the pointed object!
Following examples are also valid, but better avoid this syntax as it can make the
code really illegible:
(a + 1)[i] = 3;
// same as: *((a + 1) + i) = 3, i.e. a[i + 1] = 3
(i + 2)[a] = 0;
// same as: *((i + 2) + a) = 0, i.e. a[i + 2] = 0
Assignment and Comparison
You can use a simple assignment operator (=) to assign value of one pointer to
another if they are of the same type. If they are of different types, you must use a
typecast operator. Explicit type conversion is not necessary if one of the pointers is
generic (of void type).
Assigning the integer constant 0 to a pointer assigns a null pointer value to it. The
mnemonic NULL (defined in the standard library header files, such as stdio.h)
can be used for legibility.
Two pointers pointing into the same array may be compared by using relational
operators ==, !=, <, <=, >, and >=. Results of these operations are same as if they
were used on subscript values of array elements in question:
int *pa = &a[4], *pb = &a[2];
if (pa > pb) { ...
// this will be executed as 4 is greater than 2
}
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You can also compare pointers to zero value – this tests if pointer actually points
to anything. All pointers can be successfully tested for equality or inequality to
NULL:
if (pa == NULL) { ... }
if (pb != NULL) { ... }
Note: Comparing pointers pointing to different objects/arrays can be performed at
programmer’s responsibility — precise overview of data’s physical storage is
required.
Pointer Addition
You can use operators +, ++, and += to add an integral value to a pointer. The
result of addition is defined only if pointer points to an element of an array and if
the result is a pointer pointing into the same array (or one element beyond it).
If a pointer is declared to point to type, adding an integral value to the pointer
advances the pointer by that number of objects of type. Informally, you can think
of P+n as advancing the pointer P by (n*sizeof(type)) bytes, as long as the
pointer remains within the legal range (first element to one beyond the last element). If type has size of 10 bytes, then adding 5 to a pointer to type advances
the pointer 50 bytes in memory. In case of void type, size of the step is one byte.
For example:
int a[10];
int *pa = &a[0];
// array a containing 10 elements of int
// pa is pointer to int, pointing to a[0]
*(pa + 3) = 6;
// pa+3 is a pointer pointing to a[3],
// so a[3] now equals 6
pa++; // pa now points to the next element of array, a[1]
There is no such element as “one past the last element”, of course, but a pointer is
allowed to assume such a value. C “guarantees” that the result of addition is
defined even when pointing to one element past array. If P points to the last array
element, P+1 is legal, but P+2 is undefined.
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This allows you to write loops which access the array elements in a sequence by
means of incrementing pointer — in the last iteration you will have a pointer
pointing to one element past an array, which is legal. However, applying the indirection operator (*) to a “pointer to one past the last element” leads to undefined
behavior.
For example:
void f (some_type a[], int n) {
/* function f handles elements of array a; */
/* array a has n elements of some_type */
int i;
some_type *p = &a[0];
for (i = 0; i < n; i++) {
/* .. here we do something with *p .. */
p++;
/* .. and with the last iteration p exceeds
the last element of array a */
}
/* at this point, *p is undefined! */
}
Pointer Subtraction
Similar to addition, you can use operators -, --, and -= to subtract an integral
value from a pointer.
Also, you may subtract two pointers. Difference will equal the distance between
the two pointed addresses, in bytes.
For example:
int
int
i =
pi2
a[10];
*pi1 = &a[0], *pi2 = &[4];
pi2 - pi1;
// i equals 8
-= (i >> 1);
// pi2 = pi2 - 4: pi2 now points to a[0]
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Structures
A structure is a derived type usually representing a user-defined collection of
named members (or components). The members can be of any type, either fundamental or derived (with some restrictions to be noted later), in any sequence. In
addition, a structure member can be a bit field type not allowed elsewhere.
Unlike arrays, structures are considered single objects. The mikroC structure type
lets you handle complex data structures almost as easily as single variables.
Note: mikroC does not support anonymous structures (ANSI divergence).
Structure Declaration and Initialization
Structures are declared using the keyword struct:
struct tag { member-declarator-list };
Here, tag is the name of the structure; member-declarator-list is a list of
structure members, actually a list of variable declarations. Variables of structured
type are declared same as variables of any other type.
The member type cannot be the same as the struct type being currently declared.
However, a member can be a pointer to the structure being declared, as in the following example:
struct mystruct { mystruct s;};
struct mystruct { mystruct *ps;};
/* illegal! */
/* OK */
Also, a structure can contain previously defined structure types when declaring an
instance of a declared structure. Here is an example:
/* Structure defining a dot: */
struct Dot {float x, y;};
/* Structure defining a circle: */
struct Circle {
double r;
struct Dot center;
} o1, o2; /* declare variables o1 and o2 of circle type */
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Note that you can omit structure tag, but then you cannot declare additional
objects of this type elsewhere. For more information, see the “Untagged
Structures” below.
Structure is initialized by assigning it a comma-delimited sequence of values within braces, similar to array. Referring to declarations from the previous example:
/* Declare and initialize dots p and q: */
struct Dot p = {1., 1.}, q = {3.7, -0.5};
/* Initialize already declared circles o1 and o2: */
o1 = {1, {0, 0}};
// r is 1, center is at (0, 0)
o2 = {4, { 1.2, -3 }};
// r is 4, center is at (1.2, -3)
Incomplete Declarations
Incomplete declarations are also known as forward declarations. A pointer to a
structure type A can legally appear in the declaration of another structure B before
A has been declared:
struct A;
// incomplete
struct B {struct A *pa;};
struct A {struct B *pb;};
The first appearance of A is called incomplete because there is no definition for it
at that point. An incomplete declaration is allowed here, because the definition of
B doesn’t need the size of A.
Untagged Structures and Typedefs
If you omit the structure tag, you get an untagged structure. You can use untagged
structures to declare the identifiers in the comma-delimited struct-id-list to
be of the given structure type (or derived from it), but you cannot declare additional objects of this type elsewhere.
It is possible to create a typedef while declaring a structure, with or without a tag:
typedef struct { ... } Mystruct;
Mystruct s, *ps, arrs[10];
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Structure Assignment
Variables of same structured type may be assigned one to another by means of
simple assignment operator (=). This will copy the entire contents of the variable
to destination, regardless of the inner complexitiy of a given structure.
Note that two variables are of same structured type only if they were both defined
by the same instruction or were defined using the same type identifier. For example:
/* a and b are of the same type: */
struct {int m1, m2;} a, b;
/* But c and d are _not_ of the same type although
their structure descriptions are identical: */
struct {int m1, m2;} c;
struct {int m1, m2;} d;
Size of Structure
You can get size of the structure in memory by means of operator sizeof. Size of
the structure does not necessarily need to be equal to the sum of its members’
sizes. It is often greater due to certain limitations of memory storage.
Structures and Functions
A function can return a structure type or a pointer to a structure type:
mystruct func1();
mystruct *func2();
// func1() returns a structure
// func2() returns pointer to structure
A structure can be passed as an argument to a function in the following ways:
void func1(mystruct s);
void func2(mystruct *sptr);
// directly
// via pointer
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Structure Member Access
Structure and union members are accessed using the following two selection operators:
. (period)
-> (right arrow)
The operator . is called the direct member selector and it is used to directly access
one of the structure’s members. Suppose that the object s is of struct type S. Then
if m is a member identifier of type M declared in s, the expression
s.m
// direct access to member m
is of type M, and represents the member object m in s.
The operator -> is called the indirect (or pointer) member selector. Suppose that
ps is a pointer to s. Then if m is a member identifier of type M declared in s, the
expression
ps->m // indirect access to member m;
// identical to (*ps).m
is of type M, and represents the member object m in s. The expression ps->m is a
convenient shorthand for (*ps).m.
For example:
struct mystruct {
int i; char str[10]; double d;
} s, *sptr = &s;
.
.
.
s.i = 3;
// assign to the i member of mystruct s
sptr -> d = 1.23;
// assign to the d member of mystruct s
The expression s.m is an lvalue, provided that s is an lvalue and m is not an array
type. The expression sptr->m is an lvalue unless m is an array type.
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Accessing Nested Structures
If structure B contains a field whose type is structure A, the members of A can be
accessed by two applications of the member selectors:
struct A {
int j; double x;
};
struct B {
int i; struct A a; double d;
} s, *sptr;
//...
s.i = 3;
s.a.j = 2;
sptr->d = 1.23;
sptr->a.x = 3.14;
//
//
//
//
assign
assign
assign
assign
3 to
2 to
1.23
3.14
the i member of B
the j member of A
to the d member of B
to x member of A
Structure Uniqueness
Each structure declaration introduces a unique structure type, so that in
struct A {
int i,j; double d;
} aa, aaa;
struct B {
int i,j; double d;
} bb;
the objects aa and aaa are both of type struct A, but the objects aa and bb are of
different structure types. Structures can be assigned only if the source and destination have the same type:
aa = aaa;
aa = bb;
/* but
aa.i =
aa.j =
aa.d =
/* OK: same type, member by member assignment */
/* ILLEGAL: different types */
you can assign member by member: */
bb.i;
bb.j;
bb.d;
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Unions
Union types are derived types sharing many of the syntactic and functional features of structure types. The key difference is that a union allows only one of its
members to be “active” at any given time, the most recently changed member.
Note: mikroC does not support anonymous unions (ANSI divergence).
Union Declaration
Unions are declared same as structures, with the keyword union used instead of
struct:
union tag { member-declarator-list };
Unlike structures’ members, the value of only one of union’s members can be
stored at any time. Let’s have a simple example:
union myunion { // union tag is 'myunion'
int i;
double d;
char ch;
} mu, *pm = &mu;
The identifier mu, of type union myunion, can be used to hold a 2-byte int, a
4-byte double, or a single-byte char, but only one of these at any given time.
Size of Union
The size of a union is the size of its largest member. In our previous example, both
sizeof(union myunion) and sizeof(mu) return 4, but 2 bytes are unused
(padded) when mu holds an int object, and 3 bytes are unused when mu holds a
char.
Union Member Access
Union members can be accessed with the structure member selectors (. and ->),
but care is needed. Check the example on the following page.
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Referring to declarations from the previous example:
mu.d = 4.016;
Lcd_Out_Cp(FloatToStr(mu.d));
Lcd_Out_Cp(IntToStr(mu.i));
// OK: displays mu.d = 4.016
// peculiar result
pm->i = 3;
Lcd_Out_Cp(IntToStr(mu.i));
// OK: displays mu.i = 3
The second Lcd_Out_Cp is legal, since mu.i is an integral type. However, the bit
pattern in mu.i corresponds to parts of the previously assigned double. As such,
it probably does not provide a useful integer interpretation.
When properly converted, a pointer to a union points to each of its members, and
vice versa.
Bit Fields
Bit fields are specified numbers of bits that may or may not have an associated
identifier. Bit fields offer a way of subdividing structures into named parts of userdefined sizes.
Structures and unions can contain bit fields. Bit fields can be up to 16 bits.
You cannot take the address of a bit field.
Note: If you need to handle specific bits of 8-bit variables (char and unsigned
short) or registers, you don’t need to declare bit fields. Much more elegant solution is to use mikroC’s intrinsic ability for individual bit access — see Accessing
Individual Bits for more information.
Bit Fields Declaration
Bit fields can be declared only in structures. Declare a structure normally, and
assign individual fields like this (fields need to be unsigned):
struct tag { unsigned bitfield-declarator-list; }
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Here, tag is an optional name of the structure; bitfield-declarator-list is a list of bit
fields. Each component identifer requires a colon and its width in bits to be explicitly specified. Total width of all components cannot exceed two bytes (16 bits).
As an object, bit fields structure takes two bytes. Individual fields are packed
within two bytes from right to left. In bitfield-declarator-list, you can omit identifier(s) to create artificial “padding”, thus skipping irrelevant bits.
For example, if we need to manipulate only bits 2–4 of a register as one block, we
could create a structure:
struct {
unsigned
mybits
: 2,
: 3;
// Skip bits 0 and 1, no identifier here
// Relevant bits 2, 3, and 4
// Bits 5, 6, and 7 are implicitly left out
} myreg;
Here is an example:
typedef struct {
prescaler : 2; timeronoff : 1; postscaler : 4;} mybitfield;
which declares structured type mybitfield containing three components:
prescaler (bits 0 and 1), timeronoff (bit 2), and postscaler (bits 3, 4, 5,
and 6).
Bit Fields Access
Bit fields can be accessed in same way as the structure members. Use direct and
indirect member selector (. and ->). For example, we could work with our
previously declared mybitfield like this:
// Declare a bit field TimerControl:
mybitfield TimerControl;
void main() {
TimerControl.prescaler = 0;
TimerControl.timeronoff = 1;
TimerControl.postscaler = 3;
T2CON = TimerControl;
}
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TYPES CONVERSIONS
C is strictly typed language, with each operator, statement and function demanding
appropriately typed operands/arguments. However, we often have to use objects of
“mismatching” types in expressions. In that case, type conversion is needed.
Conversion of object of one type is changing it to the same object of another type
(i.e. applying another type to a given object). C defines a set of standard conversions for built-in types, provided by compiler when necessary.
Conversion is required in following situations:
- if statement requires an expression of particular type (according to language
definition), and we use an expression of different type,
- if operator requires an operand of particular type, and we use an operand of
different type,
- if a function requires a formal parameter of particular type, and we pass it an
object of different type,
- if an expression following the keyword return does not match the declared
function return type,
- if intializing an object (in declaration) with an object of different type.
In these situations, compiler will provide an automatic implicit conversion of
types, without any user interference. Also, user can demand conversion explicitly
by means of typecast operator. For more information, refer to Explicit
Typecasting.
Standard Conversions
Standard conversions are built in C. These conversions are performed automatically, whenever required in the program. They can be also explicitly required by
means of typecast operator (refer to Explicit Typecasting).
The basic rule of automatic (implicit) conversion is that the operand of simpler
type is converted (promoted) to the type of more complex operand. Then, type of
the result is that of more complex operand.
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Arithmetic Conversions
When you use an arithmetic expression, such as a+b, where a and b are of different arithmetic types, mikroC performs implicit type conversions before the expression is evaluated. These standard conversions include promotions of “lower” types
to “higher” types in the interests of accuracy and consistency.
Assigning a signed character object (such as a variable) to an integral object
results in automatic sign extension. Objects of type signed char always use
sign extension; objects of type unsigned char always set the high byte to zero
when converted to int.
Converting a longer integral type to a shorter type truncates the higher order bits
and leaves low-order bits unchanged. Converting a shorter integral type to a longer
type either sign-extends or zero-fills the extra bits of the new value, depending on
whether the shorter type is signed or unsigned, respectively.
Note: Conversion of floating point data into integral value (in assignments or via
explicit typecast) produces correct results only if the float value does not exceed
the scope of destination integral type.
First, any small integral types are converted according to the following rules:
1. char converts to int
2. signed char converts to int, with the same value
3. short converts to int, with the same value, sign-extended
4. unsigned short converts to unsigned int, with the same value, zero-filled
5. enum converts to int, with the same value
After this, any two values associated with an operator are either int (including
the long and unsigned modifiers), or they are float (equivalent with double
and long double in mikroC).
1. If either operand is float, the other operand is converted to float
2. Otherwise, if either operand is unsigned long, the other operand is converted
to unsigned long
3. Otherwise, if either operand is long, the other operand is converted to long
4. Otherwise, if either operand is unsigned, the other operand is converted to
unsigned
5. Otherwise, both operands are int
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The result of the expression is the same type as that of the two operands.
Here are several examples of implicit conversion:
2+3.1
5/4*3.
3.*5/4
// = 2. + 3.1 = 5.1
// = (5/4)*3. = 1*3. = 1.*3. = 3.0
// = (3.*5)/4 = (3.*5.)/4 = 15./4 = 15./4. = 3.75
Pointer Conversions
Pointer types can be converted to other pointer types using the typecasting mechanism:
char *str;
int *ip;
str = (char *)ip;
More generally, the cast (type*) will convert a pointer to type “pointer to type”.
Explicit Types Conversions (Typecasting)
In most situations, compiler will provide an automatic implicit conversion of types
where needed, without any user interference. Also, you can explicitly convert an
operand to another type using the prefix unary typecast operator:
(type) object
For example:
char a, b;
/* Following line will coerce a to unsigned int: */
(unsigned int) a;
/* Following line will coerce a to double,
then coerce b to double automatically,
resulting in double type value: */
(double) a + b;
// equivalent to ((double) a) + b;
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DECLARATIONS
Introduction to Declarations
Declaration introduces one or several names to a program – it informs the compiler what the name represents, what is its type, what are allowed operations with it,
etc. This section reviews concepts related to declarations: declarations, definitions,
declaration specifiers, and initialization.
The range of objects that can be declared includes:
- Variables
- Constants
- Functions
- Types
- Structure, union, and enumeration tags
- Structure members
- Union members
- Arrays of other types
- Statement labels
- Preprocessor macros
Declarations and Definitions
Defining declarations, also known as definitions, beside introducing the name of
an object, also establish the creation (where and when) of the object; that is, the
allocation of physical memory and its possible initialization. Referencing declarations, or just declarations, simply make their identifiers and types known to the
compiler.
Here is an overview. Declaration is also a definition, except if:
- it declares a function without specifying its body,
- it has an extern specifier, and has no initializator or body (in case of func.),
- it is a typedef declaration.
There can be many referencing declarations for the same identifier, especially in a
multifile program, but only one defining declaration for that identifier is allowed.
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Let’s have an example:
/* Here is a nondefining declaration of function max; */
/* it merely informs compiler that max is a function */
int max();
/* Here is a definition of function max: */
int max(int x, int y) {
return (x>=y) ? x : y;
}
int i;
int i;
/* Definition of variable i */
/* Error: i is already defined! */
Declarations and Declarators
A declaration is a list of names. The names are sometimes referred to as declarators or identifiers. The declaration begins with optional storage class specifiers,
type specifiers, and other modifiers. The identifiers are separated by commas and
the list is terminated by a semicolon.
Declarations of variable identifiers have the following pattern:
storage-class [type-qualifier] type var1 [=init1], var2 [=init2],
...;
where var1, var2,... are any sequence of distinct identifiers with optional initializers. Each of the variables is declared to be of type; if omitted, type defaults to
int. Specifier storage-class can take values extern, static, register, or
the default auto. Optional type-qualifier can take values const or
volatile. For more details, refer to Storage Classes and Type Qualifiers.
Here is an example of variable declaration:
/* Create 3 integer variables called x, y, and z and
initialize x and y to the values 1 and 2, respectively: */
int x = 1, y = 2, z;
// z remains uninitialized
These are all defining declarations; storage is allocated and any optional initializers are applied.
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Linkage
An executable program is usually created by compiling several independent translation units, then linking the resulting object files with preexisting libraries. The
term translation unit refers to a source code file together with any included files,
but less any source lines omitted by conditional preprocessor directives. A problem
arises when the same identifier is declared in different scopes (for example, in different files), or declared more than once in the same scope.
Linkage is the process that allows each instance of an identifier to be associated
correctly with one particular object or function. All identifiers have one of two
linkage attributes, closely related to their scope: external linkage or internal linkage. These attributes are determined by the placement and format of your declarations, together with the explicit (or implicit by default) use of the storage class
specifier static or extern.
Each instance of a particular identifier with external linkage represents the same
object or function throughout the entire set of files and libraries making up the
program. Each instance of a particular identifier with internal linkage represents
the same object or function within one file only.
Linkage Rules
Local names have internal linkage; same identifier can be used in different files to
signify different objects. Global names have external linkage; identifier signifies
the same object throughout all program files.
If the same identifier appears with both internal and external linkage within the
same file, the identifier will have internal linkage.
Internal Linkage Rules:
1. names having file scope, explicitly declared as static, have internal linkage,
2. names having file scope, explicitly declared as const and not explicitly,
declared as extern, have internal linkage,
3. typedef names have internal linkage,
4. enumeration constants have internal linkage .
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External Linkage Rule:
1. names having file scope, that do not comply to any of previously stated internal
linkage rules, have external linkage.
The storage class specifiers auto and register cannot appear in an external
declaration. For each identifier in a translation unit declared with internal linkage,
no more than one external definition can be given. An external definition is an
external declaration that also defines an object or function; that is, it also allocates
storage. If an identifier declared with external linkage is used in an expression
(other than as part of the operand of sizeof), then exactly one external definition
of that identifier must be somewhere in the entire program.
mikroC allows later declarations of external names, such as arrays, structures, and
unions, to add information to earlier declarations. Here's an example:
int a[];
struct mystruct;
.
.
.
int a[3] = {1, 2, 3};
struct mystruct {
int i, j;
};
// No size
// Tag only, no member declarators
// Supply size and initialize
// Add member declarators
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Storage Classes
Associating identifiers with objects requires each identifier to have at least two
attributes: storage class and type (sometimes referred to as data type). The mikroC
compiler deduces these attributes from implicit or explicit declarations in the
source code.
Storage class dictates the location (data segment, register, heap, or stack) of the
object and its duration or lifetime (the entire running time of the program, or during execution of some blocks of code). Storage class can be established by the
syntax of the declaration, by its placement in the source code, or by both of these
factors:
storage-class type identifier
The storage class specifiers in mikroC are:
auto
register
static
extern
Auto
Use the auto modifer to define a local variable as having a local duration. This is
the default for local variables and is rarely used. You cannot use auto with globals. See also Functions.
Register
By default, mikroC stores variables within internal microcontroller memory. Thus,
modifier register technically has no special meaning. mikroC compiler simply
ignores requests for register allocation.
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Static
Global name declared with static specifier has internal linkage, meaning that it
is local for a given file. See Linkage for more information.
Local name declared with static specifier has static duration. Use static with
a local variable to preserve the last value between successive calls to that function.
See Duration for more information.
Extern
Name declared with extern specifier has external linkage, unless it has been previously declared as having internal linkage. Declaration is not a definition if it has
extern specifier and is not initialized. The keyword extern is optional for a
function prototype.
Use the extern modifier to indicate that the actual storage and initial value of a
variable, or body of a function, is defined in a separate source code module.
Functions declared with extern are visible throughout all source files in a program, unless you redefine the function as static.
See Linkage for more information.
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Type Qualifiers
Type qualifiers const and volatile are optional in declarations and do not actually affect the type of declared object.
Qualifier const
Qualifier const implies that the declared object will not change its value during
runtime. In declarations with const qualifier, you need to initialize all the objects
in the declaration.
Effectively, mikroC treats objects declared with const qualifier same as literals or
preprocessor constants. Compiler will report an error if trying to change an object
declared with const qualifier.
For example:
const double PI = 3.14159;
Qualifier volatile
Qualifier volatile implies that variable may change its value during runtime
indepent from the program. Use the volatile modifier to indicate that a variable
can be changed by a background routine, an interrupt routine, or an I/O port.
Declaring an object to be volatile warns the compiler not to make assumptions
concerning the value of the object while evaluating expressions in which it occurs
because the value could change at any moment.
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Typedef Specifier
Specifier typedef introduces a synonym for a specified type. You can use typedef declarations to construct shorter or more meaningful names for types already
defined by the language or for types that you have declared. You cannot use the
typedef specifier inside a function definition.
The specifier typedef stands first in the declaration:
typedef <type-definition> synonym;
The typedef keyword assigns the synonym to the <type-definition>. The
synonym needs to be a valid identifier.
Declaration starting with the typedef specifier does not introduce an object or
function of a given type, but rather a new name for a given type. That is, the
typedef declaration is identical to “normal” declaration, but instead of objects, it
declares types. It is a common practice to name custom type identifiers with starting capital letter — this is not required by C.
For example:
// Let's declare a synonym for "unsigned long int":
typedef unsigned long int Distance;
// Now, synonym "Distance" can be used as type identifier:
Distance i; // declare variable i of unsigned long int
In typedef declaration, as in any declaration, you can declare several types at once.
For example:
typedef int *Pti, Array[10];
Here, Pti is synonym for type “pointer to int”, and Array is synonym for type
“array of 10 int elements”.
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asm Declaration
C allows embedding assembly in the source code by means of asm declaration.
Declarations _asm and __asm are also allowed in mikroC, and have the same
meaning. Note that you cannot use numerals as absolute addresses for SFR or
GPR variables in assembly instructions. You may use symbolic names instead
(listing will display these names as well as addresses).
You can group assembly instructions by the asm keyword (or _asm, or __asm):
asm {
block of assembly instructions
}
C comments (both single-line and multi-line) are allowed in embedded assembly
code. Assembly-style comments starting with semicolon are not allowed.
If you plan to use a certain C variable in embedded assembly only, be sure to at
least initialize it in C code; otherwise, linker will issue an error. This does not
apply to predefined globals such as PORTB.
For example, the following code will not be compiled, as linker won’t be able to
recognize variable myvar:
unsigned myvar;
void main() {
asm {
MOVLW 10 // just a test
MOVLW test_main_global_myvar_1
}
}
Adding the following line (or similar) above asm block would let linker know that
variable is used:
myvar := 0;
Note: mikroC will not check if the banks are set appropriately for your variable.
You need to set the banks manually in assembly code.
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Migration from older versions of mikroC
The syntax that is being used in the asm blocks is somewhat different than it has
been in vesion 2. The differences are:
Variable mangling is altered, and is now more in C-manner. For example, for variable named :
- _myVar, if it is global.
- FARG_+XX, if it is local (this is myVar's actual position in the local function
frame.
- _myVar_L0(+XX), if it is a local static variable (+XX to access further individual bytes).
The only types whose name remains the same in asm as it is in C are constants,
e.g. INTCON, PORTB, WREG, GIE, etc.
Accessing individual bytes is different as well. For example, if you have a global
variable "g_var", that is of type long (i.e. 4 bytes), you are to access it like this:
MOVF
_g_var+0,
register
MOVF
_g_var+1,
Hi(g_var)
MOVF
_g_var+2,
MOVF
_g_var+3,
... etc.
0 ;puts least-significant byte of g_var in W
0 ;second byte of _g_var; corresponds to
0 ;Higher(g_var)
0 ;Highest(g_var)
Syntax for retrieving address of an object is different. For objects located in flash
ROM:
MOVLW
MOVLW
MOVLW
... and
#_g_var
@#_g_var
@@#_g_var
so on.
;first byte of address
;second byte of address
;third byte of address
For objects located in RAM:
MOVLW
CONST1
MOVLW
@CONST1
... and so on.
;first byte of address
;second byte of address
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Initialization
At the time of declaration, you can set the initial value of a declared object, i.e.
initialize it. Part of the declaration which specifies the initialization is called the
initializer.
Initializers for globals and static objects must be constants or constant expressions.
The initializer for an automatic object can be any legal expression that evaluates to
an assignment-compatible value for the type of the variable involved.
Scalar types are initialized with a single expression, which can optionally be
enclosed in braces. The initial value of the object is that of the expression; the
same constraints for type and conversions apply as for simple assignments.
For example:
int i = 1;
char *s = "hello";
struct complex c = {0.1, -0.2};
// where 'complex' is a structure (float, float)
For structures or unions with automatic storage duration, the initializer must be
one of the following:
- an initializer list,
- a single expression with compatible union or structure type. In this case, the
initial value of the object is that of the expression.
For more information, refer to Structures and Unions.
Also, you can initialize arrays of character type with a literal string, optionally
enclosed in braces. Each character in the string, including the null terminator, initializes successive elements in the array. For more information, refer to Arrays.
Automatic Initialization
mikroC does not provide automatic initialization for objects. Uninitialized globals
and objects with static duration will take random values from memory.
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FUNCTIONS
Functions are central to C programming. Functions are usually defined as subprograms which return a value based on a number of input parameters. Return value
of a function can be used in expressions – technically, function call is considered
an operator like any other.
C allows a function to create results other than its return value, referred to as side
effects. Often, function return value is not used at all, depending on the side
effects. These functions are equivalent to procedures of other programming languages, such as Pascal. C does not distinguish between procedure and function –
functions play both roles.
Each program must have a single external function named main marking the entry
point of the program. Functions are usually declared as prototypes in standard or
user-supplied header files, or within program files. Functions have external linkage
by default and are normally accessible from any file in the program. This can be
restricted by using the static storage class specifier in function declaration (see
Storage Classes and Linkage).
Note: Check the PIC Specifics for more info on functions’ limitations on PIC
micros.
Function Declaration
Functions are declared in your source files or made available by linking precompiled libraries. Declaration syntax of a function is:
type function_name(parameter-declarator-list);
The function_name must be a valid identifier. This name is used to call the
function; see Function Calls for more information. The type represents the type
of function result, and can be any standard or user-defined type. For functions that
do not return value, you should use void type. The type can be omitted in global
function declarations, and function will assume int type by default.
Function type can also be a pointer. For example, float* means that the function result is a pointer to float. Generic pointer, void* is also allowed. Function
cannot return array or another function.
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Within parentheses, parameter-declarator-list is a list of formal arguments
that function takes. These declarators specify the type of each function parameter.
The compiler uses this information to check function calls for validity. If the list is
empty, function does not take any arguments. Also, if the list is void, function
also does not take any arguments; note that this is the only case when void can be
used as an argument’s type.
Unlike with variable declaration, each argument in the list needs its own type
specifier and a possible qualifier const or volatile.
Function Prototypes
A given function can be defined only once in a program, but can be declared several times, provided the declarations are compatible. If you write a nondefining
declaration of a function, i.e. without the function body, you do not have to specify
the formal arguments. This kind of declaration, commonly known as the function
prototype, allows better control over argument number and type checking, and
type conversions.
Name of the parameter in function prototype has its scope limited to the prototype.
This allows different parameter names in different declarations of the same function:
/* Here are two prototypes of the same function: */
int test(const char*)
int test(const char*p)
// declares function test
// declares the same function test
Function prototypes greatly aid in documenting code. For example, the function
Cf_Init takes two parameters: Control Port and Data Port. The question is,
which is which? The function prototype
void Cf_Init(char *ctrlport, char *dataport);
makes it clear. If a header file contains function prototypes, you can that file to get
the information you need for writing programs that call those functions. If you
include an identifier in a prototype parameter, it is used only for any later error
messages involving that parameter; it has no other effect.
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Function Definition
Function definition consists of its declaration and a function body. The function
body is technically a block – a sequence of local definitions and statements
enclosed within braces {}. All variables declared within function body are local to
the function, i.e. they have function scope.
The function itself can be defined only within the file scope. This means that function declarations cannot be nested.
To return the function result, use the return statement. Statement return in
functions of void type cannot have a parameter – in fact, you can omit the
return statement altogether if it is the last statement in the function body.
Here is a sample function definition:
/* function max returns greater one of its 2 arguments: */
int max(int x, int y) {
return (x>=y) ? x : y;
}
Here is a sample function which depends on side effects rather than return value:
/* function converts Descartes coordinates (x,y)
to polar coordinates (r,fi): */
#include <math.h>
void polar(double x, double y, double *r, double *fi) {
*r = sqrt(x * x + y * y);
*fi = (x == 0 && y == 0) ? 0 : atan2(y, x);
return; /* this line can be omitted */
}
Function Reentrancy
Limited reentrancy for functions is allowed. The functions that don't have their
own function frame (no arguments and local variables) can be called both from the
interrupt and the "main" thread. Functions that have input arguments and/or local
variables can be called only from one of the before mentioned program threads.
Check Indirect Function Calls.
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Function Calls
A function is called with actual arguments placed in the same sequence as their
matching formal parameters. Use a function-call operator ():
function_name(expression_1, ... , expression_n)
Each expression in the function call is an actual argument. Number and types of
actual arguments should match those of formal function parameters. If types disagree, implicit type conversions rules apply. Actual arguments can be of any complexity, but you should not depend on their order of evaluation, because it is not
specified.
Upon function call, all formal parameters are created as local objects initialized by
values of actual arguments. Upon return from a function, temporary object is created in the place of the call, and it is initialized by the expression of return statement. This means that function call as an operand in complex expression is treated
as the function result.
If the function is without result (type void) or you don’t need the result, you can
write the function call as a self-contained expression.
In C, scalar parameters are always passed to function by value. A function can
modify the values of its formal parameters, but this has no effect on the actual
arguments in the calling routine. You can pass scalar object by the address by
declaring a formal parameter to be a pointer. Then, use the indirection operator *
to access the pointed object.
Argument Conversions
When a function prototype has not been previously declared, mikroC converts
integral arguments to a function call according to the integral widening (expansion) rules described in Standard Conversions. When a function prototype is in
scope, mikroC converts the given argument to the type of the declared parameter
as if by assignment.
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If a prototype is present, the number of arguments must match. The types need to
be compatible only to the extent that an assignment can legally convert them. You
can always use an explicit cast to convert an argument to a type that is acceptable
to a function prototype.
Note: If your function prototype does not match the actual function definition,
mikroC will detect this if and only if that definition is in the same compilation unit
as the prototype. If you create a library of routines with a corresponding header
file of prototypes, consider including that header file when you compile the
library, so that any discrepancies between the prototypes and the actual definitions
will be caught.
The compiler is also able to force arguments to the proper type. Suppose you have
the following code:
int limit = 32;
char ch = 'A';
long res;
extern long func(long par1, long par2);
main() {
//...
res = func(limit, ch);
}
// prototype
// function call
Since it has the function prototype for func, this program converts limit and ch
to long, using the standard rules of assignment, before it places them on the stack
for the call to func.
Without the function prototype, limit and ch would have been placed on the
stack as an integer and a character, respectively; in that case, the stack passed to
func would not match in size or content what func was expecting, leading to
problems.
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Ellipsis ('...') Operator
An ellipsis ('...') consists of three successive periods with no whitespace intervening. You can use an ellipsis in the formal argument lists of function prototypes to
indicate a variable number of arguments, or arguments with varying types. For
example:
void func (int n, char ch, ...);
This declaration indicates that func will be defined in such a way that calls must
have at least two arguments, an int and a char, but can also have any number of
additional arguments.
Example:
#include <stdarg.h>
int addvararg(char a1,...){
va_list ap;
char temp;
va_start(ap,a1);
while( temp = va_arg(ap,char))
a1 += temp;
return a1;
}
int res;
void main() {
res = addvararg(1,2,3,4,5,0);
res = addvararg(1,2,3,4,5,6,7,8,9,10,0);
}//~!
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OPERATORS
Operators are tokens that trigger some computation when applied to variables and
other objects in an expression.
mikroC recognizes following operators:
- Arithmetic Operators
- Assignment Operators
- Bitwise Operators
- Logical Operators
- Reference/Indirect Operators
- Relational Operators
- Structure Member Selectors
(see Pointer Arithmetic)
(see Structure Member Access)
- Comma Operator ,
- Conditional Operator ? :
(see Comma Expressions)
- Array subscript operator []
- Function call operator ()
(see Arrays)
(see Function Calls)
- sizeof Operator
- Preprocessor Operators # and ##
(see Preprocessor Operators)
Operators Precedence and Associativity
There are 15 precedence categories, some of which contain only one operator.
Operators in the same category have equal precedence with each other.
Table on the following page sums all mikroC operators.
Where duplicates of operators appear in the table, the first occurrence is unary, the
second binary. Each category has an associativity rule: left-to-right or right-to-left.
In the absence of parentheses, these rules resolve the grouping of expressions with
operators of equal precedence.
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Precedence
Operands
Operators
Associativity
15
2
()
14
1
!
&
~
++
(type)
13
2
*
/
12
2
+
-
11
2
<<
10
2
<
9
2
==
8
2
&
left-to-right
7
2
^
left-to-right
6
2
|
left-to-right
5
2
&&
left-to-right
4
2
||
left-to-right
3
3
?:
left-to-right
2
2
=
&=
1
2
,
[]
.
left-to-right
->
-+
sizeof
-
*
right-to-left
left-to-right
%
left-to-right
left-to-right
>>
<=
>
left-to-right
>=
left-to-right
!=
*=
^=
/=
|=
%=
<<=
+=
-=
>>=
right-to-left
left-to-right
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Arithmetic Operators
Arithmetic operators are used to perform mathematical computations. They have
numerical operands and return numerical results. Type char technically represents
small integers, so char variables can used as operands in arithmetic operations.
All of arithmetic operators associate from left to right.
Operator
Operation
Precedence
+
addition
12
-
subtraction
12
*
multiplication
13
/
division
13
%
returns the remainder of integer division (cannot be used with floating points)
13
+ (unary)
unary plus does not affect the operand
14
- (unary)
unary minus changes the sign of operand
14
++
increment adds one to the value of the
operand
14
--
decrement subtracts one from the value of the
operand
14
Note: Operator * is context sensitive and can also represent the pointer reference
operator. See Pointers for more information.
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Binary Arithmetic Operators
Division of two integers returns an integer, while remainder is simply truncated:
/* for example: */
7 / 4;
// equals 1
7 * 3 / 4;
// equals 5
/* but: */
7. * 3./ 4.;
// equals 5.25 as we are working with floats
Remainder operand % works only with integers; sign of result is equal to the sign
of first operand:
/* for example:
9 % 3;
//
7 % 3;
//
-7 % 3;
//
*/
equals 0
equals 1
equals -1
We can use arithmetic operators for manipulating characters:
'A' + 32;
'G' - 'A' + 'a';
// equals 'a' (ASCII only)
// equals 'g' (both ASCII and EBCDIC)
Unary Arithmetic Operators
Unary operators ++ and -- are the only operators in C which can be either prefix
(e.g. ++k, --k) or postfix (e.g. k++, k--).
When used as prefix, operators ++ and -- (preincrement and predecrement) add or
subtract one from the value of operand before the evaluation. When used as suffix,
operators ++ and -- add or subtract one from the value of operand after the evaluation.
For example:
int j = 5; j = ++k;
/* k = k + 1, j = k, which gives us j = 6, k = 6 */
int j = 5; j = k++;
/* j = k, k = k + 1, which gives us j = 5, k = 6 */
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Relational Operators
Use relational operators to test equality or inequality of expressions. If the expression evaluates to true, it returns 1; otherwise it returns 0.
All relational operators associate from left to right.
Relational Operators Overview
Operator
Operation
Precedence
==
equal
9
!=
not equal
9
>
greater than
10
<
less than
10
>=
greater than or equal
10
<=
less than or equal
10
Relational Operators in Expressions
Precedence of arithmetic and relational operators was designated in such a way to
allow complex expressions without parentheses to have expected meaning:
a + 5 >= c - 1.0 / e
// i.e. (a + 5) >= (c - (1.0 / e))
Always bear in mind that relational operators return either 0 or 1. Consider the following examples:
8 == 13 > 5
14 > 5 < 3
a < b < 5
// returns 0: 8==(13>5), 8==1, 0
// returns 1: (14>5)<3, 1<3, 1
// returns 1: (a<b)<5, (0 or 1)<5, 1
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Bitwise Operators
Use the bitwise operators to modify the individual bits of numerical operands.
Bitwise operators associate from left to right. The only exception is the bitwise
complement operator ~ which associates from right to left.
Bitwise Operators Overview
Operator
Operation
Precedence
&
bitwise AND; returns 1 if both bits are 1, otherwise returns 0
9
|
bitwise (inclusive) OR; returns 1 if either or
both bits are 1, otherwise returns 0
9
^
bitwise exclusive OR (XOR); returns 1 if the
bits are complementary, otherwise 0
10
~
bitwise complement (unary); inverts each bit
10
>>
bitwise shift left; moves the bits to the left,
see below
10
<<
bitwise shift right; moves the bits to the right,
see below
10
Note: Operator & can also be the pointer reference operator. Refer to Pointers for
more information.
Bitwise operators &, |, and ^ perform logical operations on appropriate pairs of
bits of their operands. For example:
0x1234 & 0x5678;
/* equals 0x1230 */
/* because ..
0x1234 : 0001 0010 0011 0100
0x5678 : 0101 0110 0111 1000
--------------------------------&
: 0001 0010 0011 0000
.. that is, 0x1230 */
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/* Similarly: */
0x1234 | 0x5678;
0x1234 ^ 0x5678;
~ 0x1234;
/* equals 0x567C */
/* equals 0x444C */
/* equals 0xEDCB */
Bitwise Shift Operators
Binary operators << and >> move the bits of the left operand for a number of positions specified by the right operand, to the left or right, respectively. Right operand
has to be positive.
With shift left (<<), left most bits are discarded, and “new” bits on the right are
assigned zeroes. Thus, shifting unsigned operand to left by n positions is equivalent to multiplying it by 2n if all the discarded bits are zero. This is also true for
signed operands if all the discarded bits are equal to sign bit.
000001 <<
0x3801 <<
5;
4;
/* equals 000040 */
/* equals 0x8010, overflow! */
With shift right (>>), right most bits are discarded, and the “freed” bits on the left
are assigned zeroes (in case of unsigned operand) or the value of the sign bit (in
case of signed operand). Shifting operand to right by n positions is equivalent to
dividing it by 2n.
0xFF56 >>
0xFF56u >>
4;
4;
/* equals 0xFFF5 */
/* equals 0x0FF5 */
Bitwise vs. Logical
Be aware of the principle difference between how bitwise and logical operators
work. For example:
0222222 & 0555555;
0222222 && 0555555;
/* equals 000000 */
/* equals 1 */
~ 0x1234;
! 0x1234;
/* equals 0xEDCB */
/* equals 0 */
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Logical Operators
Operands of logical operations are considered true or false, that is non-zero or
zero. Logical operators always return 1 or 0. Operands in a logical expression
must be of scalar type.
Logical operators && and || associate from left to right. Logical negation operator
! associates from right to left.
Logical Operators Overview
Operator
Operation
Precedence
&&
logical AND
5
||
logical OR
4
!
logical negation
14
Precedence of logical, relational, and arithmetic operators was chosen in such a
way to allow complex expressions without parentheses to have expected meaning:
c >= '0' && c <= '9'; // reads as: (c>='0') && (c<='9')
a + 1 == b || ! f(x;) // reads as: ((a+1)== b) || (!(f(x)))
Logical AND (&&) returns 1 only if both expressions evaluate to be nonzero, otherwise returns 0. If the first expression evaluates to false, the second expression is
not evaluated. For example:
a > b && c < d;
// reads as: (a>b) && (c<d)
// if (a>b) is false (0), (c<d) will not be evaluated
Logical OR (||) returns 1 if either of the expressions evaluate to be nonzero, otherwise returns 0. If the first expression evaluates to true, the second expression is
not evaluated. For example:
a && b || c && d;
// reads as: (a && b) || (c && d)
// if (a&&b) is true (1), (c&&d) will not be evaluated
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Logical Expressions and Side Effects
General rule with complex logical expressions is that the evaluation of consecutive
logical operands stops the very moment the final result is known. For example, if
we have an expression:
a && b && c
where a is false (0), then operands b and c will not be evaluated. This is very
important if b and c are expressions, as their possible side effects will not take
place!
Logical vs. Bitwise
Be aware of the principle difference between how bitwise and logical operators
work. For example:
0222222 & 0555555
0222222 && 0555555
/* equals 000000 */
/* equals 1 */
~ 0x1234
! 0x1234
/* equals 0xEDCB */
/* equals 0 */
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Conditional Operator ? :
The conditional operator ? : is the only ternary operator in C. Syntax of the conditional operator is:
expression1 ? expression2 : expression3
Expression1 evaluates first. If its value is true, then expression2 evaluates
and expression3 is ignored. If expression1 evaluates to false, then expression3 evaluates and expression2 is ignored. The result will be the value of
either expression2 or expression3 depending upon which evaluates. The fact
that only one of these two expressions evaluates is very important if you expect
them to produce side effects!
Conditional operator associates from right to left.
Here are a couple of practical examples:
/* Find max(a, b): */
max = (a > b) ? a : b;
/* Convert small letter to capital: */
/* (no parentheses are actually necessary) */
c = (c >= 'a' && c <= 'z') ? (c - 32) : c;
Conditional Operator Rules
Expression1 must be a scalar expression; expression2 and expression3
must obey one of the following rules:
1. Both of arithmetic type; expression2 and expression3 are subject to the
usual arithmetic conversions, which determines the resulting type.
2. Both of compatible struct or union types. The resulting type is the structure or
union type of expression2 and expression3.
3. Both of void type. The resulting type is void.
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4. Both of type pointer to qualified or unqualified versions of compatible types.
The resulting type is a pointer to a type qualified with all the type qualifiers of
the types pointed to by both operands.
5. One operand is a pointer, and the other is a null pointer constant. The resulting
type is a pointer to a type qualified with all the type qualifiers of the types
pointed to by both operands.
6. One operand is a pointer to an object or incomplete type, and the other is a
pointer to a qualified or unqualified version of void. The resulting type is that
of the non-pointer-to-void operand.
Assignment Operators
Unlike many other programming languages, C treats value assignment as an operation (represented by an operator) rather than instruction.
Simple Assignment Operator
For a common value assignment, we use a simple assignment operator (=) :
expression1 = expression2
Expression1 is an object (memory location) to which we assign value of
expression2. Operand expression1 has to be a lvalue, and expression2 can
be any expression. The assignment expression itself is not an lvalue.
If expression1 and expression2 are of different types, result of the expression2 will be converted to the type of expression1, if necessary. Refer to Type
Conversions for more information.
Compound Assignment Operators
C allows more comlex assignments by means of compound assignment operators.
Syntax of compound assignment operators is:
expression1 op= expression2
where op can be one of binary operators +, -, *, /, %, &, |, ^, <<, or >>.
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Thus, we have 10 different compound assignment operators: +=, -=, *=, /=,
%=, &=, |=, ^=, <<=, and >>=. All of these associate from right to left. Spaces
separating compound operators (e.g. + =) will generate error.
Compound assignment has the same effect as
expression1 = expression1 op expression2
except the lvalue expression1 is evaluated only once. For example,
expression1 += expression2
is the same as
expression1 = expression1 + expression2
Assignment Rules
For both simple and compound assignment, the operands expression1 and
expression2 must obey one of the following rules:
1. expression1 is a qualified or unqualified arithmetic type and expression2
is an arithmetic type.
2. expression1 has a qualified or unqualified version of a structure or union
type compatible with the type of expression2.
3. expression1 and expression2 are pointers to qualified or unqualified
versions of compatible types, and the type pointed to by the left has all the
qualifiers of the type pointed to by the right.
4. Either expression1 or expression2 is a pointer to an object or incomplete
type and the other is a pointer to a qualified or unqualified version of void.
The type pointed to by the left has all the qualifiers of the type pointed to by the
right.
5. expression1 is a pointer and expression2 is a null pointer constant.
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Sizeof Operator
Prefix unary operator sizeof returns an integer constant that gives the size in
bytes of how much memory space is used by its operand (determined by its type,
with some exceptions).
Operator sizeof can take either a type identifier or an unary expression as an
operand. You cannot use sizeof with expressions of function type, incomplete
types, parenthesized names of such types, or with an lvalue that designates a bit
field object.
Sizeof Applied to Expression
If applied to expression, size of the operand is determined without evaluating the
expression (and therefore without side effects). Result of the operation will be the
size of the type of the expression’s result.
Sizeof Applied to Type
If applied to a type identifier, sizeof returns the size of the specified type. Unit
for type size is the sizeof(char) which is equivalent to one byte. Operation
sizeof(char) gives the result 1, whether the char is signed or unsigned.
sizeof(char)
sizeof(int)
sizeof(unsigned long)
/* returns 1 */
/* returns 2 */
/* returns 4 */
When the operand is a non-parameter of array type, the result is the total number
of bytes in the array (in other words, an array name is not converted to a pointer
type):
int i, j, a[10];
//...
j = sizeof(a[1]);
i = sizeof(a);
/* j = sizeof(int) = 2 */
/* i = 10*sizeof(int) = 20 */
If the operand is a parameter declared as array type or function type, sizeof
gives the size of the pointer. When applied to structures and unions, sizeof gives
the total number of bytes, including any padding. Operator sizeof cannot be
applied to a function.
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EXPRESSIONS
An expression is a sequence of operators, operands, and punctuators that specifies
a computation. Formally, expressions are defined recursively: subexpressions can
be nested without formal limit. However, the compiler will report an out-of-memory error if it can’t compile an expression that is too complex.
In ANSI C, the primary expressions are: constant (also referred to as literal), identifier, and (expression), defined recursively.
Expressions are evaluated according to certain conversion, grouping, associativity,
and precedence rules that depend on the operators used, the presence of parentheses, and the data types of the operands. The precedence and associativity of the
operators are summarized in Operator Precedence and Associativity. The way
operands and subexpressions are grouped does not necessarily specify the actual
order in which they are evaluated by mikroC.
Expressions can produce an lvalue, an rvalue, or no value. Expressions might
cause side effects whether they produce a value or not.
Comma Expressions
One of the specifics of C is that it allows you to use comma as a sequence operator to form the so-called comma expressions or sequences. Comma expression is a
comma-delimited list of expressions – it is formally treated as a single expression
so it can be used in places where an expression is expected. The following
sequence:
expression_1, expression_2;
results in the left-to-right evaluation of each expression, with the value and type of
expression_2 giving the result of the whole expression. Result of expression_1 is discarded.
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Binary operator comma (,) has the lowest precedence and associates from left to
right, so that a, b, c is same as (a, b), c. This allows us to write sequences
with any number of expressions:
expression_1, expression_2, ... expression_n;
this results in the left-to-right evaluation of each expression, with the value and
type of expression_n giving the result of the whole expression. Results of other
expressions are discarded, but their (possible) side-effect do occur.
For example:
result = (a = 5, b /= 2, c++);
/* returns preincremented value of variable c, but also
intializes a, divides b by 2, and increments c */
result = (x = 10, y = x + 3, x--, z -= x * 3 - --y);
/* returns computed value of variable z,
and also computes x and y */
Note
Do not confuse comma operator (sequence operator) with the comma punctuator
which separates elements in a function argument list and initializator lists. Mixing
the two uses of comma is legal, but you must use parentheses to distinguish them.
To avoid ambiguity with the commas in function argument and initializer lists, use
parentheses. For example,
func(i, (j = 1, j + 4), k);
calls function func with three arguments (i, 5, k), not four.
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STATEMENTS
Statements specify the flow of control as a program executes. In the absence of
specific jump and selection statements, statements are executed sequentially in the
order of appearance in the source code.
Statements can be roughly divided into:
- Labeled Statements
- Expression Statements
- Selection Statements
- Iteration Statements (Loops)
- Jump Statements
- Compound Statements (Blocks)
Labeled Statements
Every statement in program can be labeled. Label is an identifier added before the
statement like this:
label_identifier : statement;
There is no special declaration of a label – it just “tags” the statement.
Label_identifier has a function scope and label cannot be redefined within
the same function.
Labels have their own namespace: label identifier can match any other identifier in
the program.
A statement can be labeled for two reasons:
1. The label identifier serves as a target for the unconditional goto statement,
2. The label identifier serves as a target for the switch statement. For this
purpose, only case and default labeled statements are used:
case constant-expression : statement
default : statement
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Expression Statements
Any expression followed by a semicolon forms an expression statement:
expression;
mikroC executes an expression statement by evaluating the expression. All side
effects from this evaluation are completed before the next statement is executed.
Most expression statements are assignment statements or function calls.
The null statement is a special case, consisting of a single semicolon (;). The null
statement does nothing, and is therefore useful in situations where the mikroC syntax expects a statement but your program does not need one. For example, null
statement is commonly used in “empty” loops:
for (; *q++ = *p++ ;);
/* body of this loop is a null statement */
Selection Statements
Selection or flow-control statements select from alternative courses of action by
testing certain values. There are two types of selection statements in C: if
and switch.
If Statement
Use the if statement to implement a conditional statement. Syntax of the if
statement is:
if (expression) statement1 [else statement2]
When expression evaluates to true, statement1 executes. If expression is
false, statement2 executes. The expression must evaluate to an integral
value; otherwise, the condition is ill-formed. Parentheses around the expression
are mandatory.
The else keyword is optional, but no statements can come between the if and
the else.
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Nested if statements
Nested if statements require additional attention. General rule is that the nested
conditionals are parsed starting from the innermost conditional, with each else
bound to the nearest available if on its left:
if (expression1) statement1
else if (expression2)
if (expression3) statement2
else statement3
/* this belongs to: if (expression3) */
else statement4
/* this belongs to: if (expression2) */
Note: The #if and #else preprocessor statements (directives) look similar to the
if and else statements, but have very different effects. They control which
source file lines are compiled and which are ignored. See Preprocessor for more
information.
Switch Statement
Use the switch statement to pass control to a specific program branch, based on a
certain condition. Syntax of switch statement is:
switch (expression) {
case constant-expression_1 : statement_1;
.
.
.
case constant-expression_n : statement_n;
[default : statement;]
}
First, the expression (condition) is evaluated. The switch statement then
compares it to all the available constant-expressions following the keyword
case. If the match is found, switch passes control to that matching case, at
which point the statement following the match evaluates. Note that
constant-expressions must evaluate to integer. There cannot be two same
constant-expressions evaluating to same value.
Parantheses around expression are mandatory.
.
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Upon finding a match, program flow continues normally: following instructions
will be executed in natural order regardless of the possible case label. If no case
satisfies the condition, the default case evaluates (if the label default is specified).
For example, if variable i has value between 1 and 3, following switch would
always return it as 4:
switch
case
case
case
}
(i) {
1: i++;
2: i++;
3: i++;
To avoid evaluating any other cases and relinquish control from the switch, terminate each case with break.
Conditional switch statements can be nested – labels case and default are
then assigned to the innermost enclosing switch statement.
Here is a simple example with switch. Let’s assume we have a variable with only
3 different states (0, 1, or 2) and a corresponding function (event) for each of these
states. This is how we could switch the code to the appopriate routine:
switch (state) {
case 0: Lo(); break;
case 1: Mid(); break;
case 2: Hi(); break;
default: Message("Invalid state!");
}
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Iteration Statements
Iteration statements let you loop a set of statements. There are three forms of iteration statements in C: while, do, and for.
While Statement
Use the while keyword to conditionally iterate a statement. Syntax of while
statement is:
while (expression) statement
The statement executes repeatedly until the value of expression is false. The test
takes place before statement executes. Thus, if expression evaluates to false
on the first pass, the loop does not execute.
Parentheses around expression are mandatory.
Here is an example of calculating scalar product of two vectors, using the while
statement:
int s = 0, i = 0;
while (i < n) {
s += a[i] * b[i];
i++;
}
Note that body of a loop can be a null statement. For example:
while (*q++ = *p++);
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Do Statement
The do statement executes until the condition becomes false. Syntax of do statement is:
do statement while (expression);
The statement is executed repeatedly as long as the value of expression
remains non-zero. The expression is evaluated after each iteration, so the loop
will execute statement at least once.
Parentheses around expression are mandatory.
Note that do is the only control structure in C which explicitly ends with semicolon (;). Other control structures end with statement which means that they
implicitly include a semicolon or a closing brace.
Here is an example of calculating scalar product of two vectors, using the do
statement:
s = 0; i = 0;
do {
s += a[i] * b[i];
i++;
} while (i < n);
For Statement
The for statement implements an iterative loop. Syntax of for statement is:
for ([init-exp]; [condition-exp]; [increment-exp]) statement
Before the first iteration of the loop, expression init-exp sets the starting variables for the loop. You cannot pass declarations in init-exp.
Expression condition-exp is checked before the first entry into the block;
statement is executed repeatedly until the value of condition-exp is false.
After each iteration of the loop, increment-exp increments a loop counter.
Consequently, i++ is functionally the same as ++i.
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All the expressions are optional. If condition-exp is left out, it is assumed to be
always true. Thus, “empty” for statement is commonly used to create an endless
loop in C:
for ( ; ; ) {...}
The only way to break out of this loop is by means of break statement.
Here is an example of calculating scalar product of two vectors, using the for
statement:
for (s = 0, i = 0; i < n; i++) s += a[i] * b[i];
You can also do it like this:
/* valid, but ugly */
for (s = 0, i = 0; i < n; s += a[i] * b[i], i++);
but this is considered a bad programming style. Although legal, calculating the
sum should not be a part of the incrementing expression, because it is not in the
service of loop routine. Note that we used a null statement (;) for a loop body.
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Jump Statements
A jump statement, when executed, transfers control unconditionally. There are four
such statements in mikroC: break, continue, goto, and return.
Break Statement
Sometimes, you might need to stop the loop from within its body. Use the break
statement within loops to pass control to the first statement following the innermost switch, for, while, or do block.
Break is commonly used in switch statements to stop its execution upon the first
positive match. For example:
switch (state) {
case 0: Lo(); break;
case 1: Mid(); break;
case 2: Hi(); break;
default: Message("Invalid state!");
}
Continue Statement
You can use the continue statement within loops (while, do, for) to “skip the
cycle”. It passes control to the end of the innermost enclosing end brace belonging
to a looping construct. At that point the loop continuation condition is re-evaluated. This means that continue demands the next iteration if loop continuation condition is true.
Goto Statement
Use the goto statement to unconditionally jump to a local label — for more information on labels, refer to Labeled Statements. Syntax of goto statement is:
goto label_identifier;
This will transfer control to the location of a local label specified by
label_identifier. The label_identifier has to be a name of the label
within the same function in which the goto statement is. The goto line can come
before or after the label.
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You can use goto to break out from any level of nested control structures. But,
goto cannot be used to jump into block while skipping that block’s initializations
– for example, jumping into loop’s body, etc.
Use of goto statement is generally discouraged as practically every algorithm can
be realized without it, resulting in legible structured programs. One possible application of goto statement is breaking out from deeply nested control structures:
for (...) {
for (...) {
...
if (disaster) goto Error;
...
}
}
.
.
.
Error: /* error handling code */
Return Statement
Use the return statement to exit from the current function back to the calling
routine, optionally returning a value. Syntax is:
return [expression];
This will evaluate the expression and return the result. Returned value will be
automatically converted to the expected function type, if needed. The expression is optional; if omitted, function will return a random value from memory.
Note: Statement return in functions of void type cannot have an expression –
in fact, you can omit the return statement altogether if it is the last statement in
the function body.
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Compound Statements (Blocks)
A compound statement, or block, is a list (possibly empty) of statements enclosed
in matching braces {}. Syntactically, a block can be considered to be a single
statement, but it also plays a role in the scoping of identifiers. An identifier
declared within a block has a scope starting at the point of declaration and ending
at the closing brace. Blocks can be nested to any depth up to the limits of memory.
For example, for loop expects one statement in its body, so we can pass it a compound statement:
for (i = 0; i < n; i++) {
int temp = a[i];
a[i] = b[i];
b[i] = temp;
}
Note that, unlike other statements, compound statements do not end with semicolon (;), i.e. there is never a semicolon following the closing brace.
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PREPROCESSOR
Preprocessor is an integrated text processor which prepares the source code for
compiling. Preprocessor allows:
- inserting text from a specifed file to a certain point in code,
- replacing specific lexical symbols with other symbols,
- conditional compiling which conditionally includes or omits parts of code.
Note that preprocessor analyzes text at token level, not at individual character
level. Preprocessor is controled by means of preprocessor directives and preprocessor operators.
Preprocessor Directives
Any line in source code with a leading # is taken as a preprocessing directive (or
control line), unless the # is within a string literal, in a character constant, or
embedded in a comment. The initial # can be preceded or followed by whitespace
(excluding new lines).
The null directive consists of a line containing the single character #. This line is
always ignored.
Preprocessor directives are usually placed at the beginning of the source code, but
they can legally appear at any point in a program. The mikroC preprocessor
detects preprocessor directives and parses the tokens embedded in them. Directive
is in effect from its declaration to the end of the program file.
mikroC supports standard preprocessor directives:
# (null directive)
#define
#elif
#else
#endif
#error
#if
#ifndef
#ifndef
#include
#line
#undef
Note: #pragma directive is under construction.
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Line Continuation with Backslash
If you need to break directive into multiple lines, you can do it by ending the line
with a backslash (\):
#define MACRO
This directive continues to \
the following line.
Macros
Macros provide a mechanism for token replacement, prior to compilation, with or
without a set of formal, function-like parameters.
Defining Macros and Macro Expansions
The #define directive defines a macro:
#define macro_identifier <token_sequence>
Each occurrence of macro_identifier in the source code following this control
line will be replaced in the original position with the possibly empty
token_sequence (there are some exceptions, which are noted later). Such
replacements are known as macro expansions. The token_sequence is sometimes called body of the macro. An empty token sequence results in the removal of
each affected macro identifier from the source code.
No semicolon (;) is needed to terminate a preprocessor directive. Any character
found in the token sequence, including semicolons, will appear in the macro
expansion. The token_sequence terminates at the first non-backslashed new
line encountered. Any sequence of whitespace, including comments in the token
sequence, is replaced with a single-space character.
After each individual macro expansion, a further scan is made of the newly
expanded text. This allows for the possibility of nested macros: The expanded text
can contain macro identifiers that are subject to replacement. However, if the
macro expands into what looks like a preprocessing directive, such a directive will
not be recognized by the preprocessor. Any occurrences of the macro identifier
found within literal strings, character constants, or comments in the source code
are not expanded
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A macro won’t be expanded during its own expansion (so #define MACRO
MACRO won’t expand indefinitely).
Let’s have an example:
/* Here are some simple macros: */
#define ERR_MSG "Out of range!"
#define EVERLOOP for( ; ; )
/* which we could use like this: */
main() {
EVERLOOP {
...
if (error) {Lcd_Out_Cp(ERR_MSG); break;}
...
}
}
Attempting to redefine an already defined macro identifier will result in a warning
unless the new definition is exactly the same token-by-token definition as the
existing one. The preferred strategy where definitions might exist in other header
files is as follows:
#ifndef BLOCK_SIZE
#define BLOCK_SIZE 512
#endif
The middle line is bypassed if BLOCK_SIZE is currently defined; if BLOCK_SIZE
is not currently defined, the middle line is invoked to define it.
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Macros with Parameters
The following syntax is used to define a macro with parameters:
#define macro_identifier(<arg_list>) token_sequence
Note there can be no whitespace between the macro_identifier and the “(”.
The optional arg_list is a sequence of identifiers separated by commas, not
unlike the argument list of a C function. Each comma-delimited identifier plays
the role of a formal argument or placeholder.
Such macros are called by writing
macro_identifier(<actual_arg_list>)
in the subsequent source code. The syntax is identical to that of a function call;
indeed, many standard library C “functions” are implemented as macros.
However, there are some important semantic differences.
The optional actual_arg_list must contain the same number of comma-delimited token sequences, known as actual arguments, as found in the formal
arg_list of the #define line – there must be an actual argument for each formal argument. An error will be reported if the number of arguments in the two
lists is different.
A macro call results in two sets of replacements. First, the macro identifier and the
parenthesis-enclosed arguments are replaced by the token sequence. Next, any formal arguments occurring in the token sequence are replaced by the corresponding
real arguments appearing in the actual_arg_list. As with simple macro definitions, rescanning occurs to detect any embedded macro identifiers eligible for
expansion.
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Here is a simple example:
// A simple macro which returns greater of its 2 arguments:
#define _MAX(A, B) ((A) > (B)) ? (A) : (B)
// Let's call it:
x = _MAX(a + b, c + d);
/* Preprocessor will transform the previous line into:
x = ((a + b) > (c + d)) ? (a + b) : (c + d) */
It is highly recommended to put parentheses around each of the arguments in
macro body – this will avoid possible problems with operator precedence.
Undefining Macros
You can undefine a macro using the #undef directive.
#undef macro_identifier
Directive #undef detaches any previous token sequence from the macro_identifier; the macro definition has been forgotten, and the macro_identifier is
undefined. No macro expansion occurs within #undef lines.
The state of being defined or undefined is an important property of an identifier,
regardless of the actual definition. The #ifdef and #ifndef conditional directives, used to test whether any identifier is currently defined or not, offer a flexible
mechanism for controlling many aspects of a compilation.
After a macro identifier has been undefined, it can be redefined with #define,
using the same or a different token sequence.
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File Inclusion
The preprocessor directive #include pulls in header files (extension .h) into the
source code. Do not rely on preprocessor to include source files (extension .c) —
see Projects for more information.
The syntax of #include directive has two formats:
#include <header_name>
#include "header_name"
The preprocessor removes the #include line and replaces it with the entire text
of the header file at that point in the source code. The placement of the #include
can therefore influence the scope and duration of any identifiers in the included
file.
The difference between the two formats lies in the searching algorithm employed
in trying to locate the include file.
If #include directive was used with the <header_name> version, the search is
made successively in each of the following locations, in this particular order:
1. mikroC installation folder > “include” folder,
2. your custom search paths.
The "header_name" version specifies a user-supplied include file; mikroC will
look for the header file in following locations, in this particular order:
1. the project folder (folder which contains the project file .ppc),
2. mikroC installation folder > “include” folder,
3. your custom search paths.
Explicit Path
If you place an explicit path in the header_name, only that directory will be
searched. For example:
#include "C:\my_files\test.h"
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Note: There is also a third version of #include directive, rarely used, which
assumes that neither < nor " appears as the first non-whitespace character following #include:
#include macro_identifier
It assumes a macro definition exists that will expand the macro identifier into a
valid delimited header name with either of the <header_name> or
"header_name" formats.
Preprocessor Operators
The # (pound sign) is a preprocessor directive when it occurs as the first nonwhitespace character on a line. Also, # and ## perform operator replacement and
merging during the preprocessor scanning phase.
Operator #
In C preprocessor, character sequence enclosed by quotes is considered a token
and its content is not analyzed. This means that macro names within quotes are not
expanded.
If you need an actual argument (the exact sequence of characters within quotes) as
result of preprocessing, you can use the # operator in macro body. It can be placed
in front of a formal macro argument in definition in order to convert the actual
argument to a string after replacement.
For example, let’s have macro LCD_PRINT for printing variable name and value
on LCD:
#define LCD_PRINT(val)
Lcd_Out_Cp(#val ": "); \
Lcd_Out_Cp(IntToStr(val));
(note the backslash as a line-continuation symbol)
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Now, the following code,
LCD_PRINT(temp)
will be preprocessed to this:
Lcd_Out_Cp("temp" ": "); Lcd_Out_Cp(IntToStr(temp));
Operator ##
Operator ## is used for token pasting: you can paste (or merge) two tokens together by placing ## in between them (plus optional whitespace on either side). The
preprocessor removes the whitespace and the ##, combining the separate tokens
into one new token. This is commonly used for constructing identifiers.
For example, we could define macro SPLICE for pasting two tokens into one identifier:
#define SPLICE(x,y) x ## _ ## y
Now, the call SPLICE(cnt, 2) expands to identifier cnt_2.
Note: mikroC does not support the older nonportable method of token pasting
using (l/**/r).
Conditional Compilation
Conditional compilation directives are typically used to make source programs
easy to change and easy to compile in different execution environments. mikroC
supports conditional compilation by replacing the appropriate source-code lines
with a blank line.
All conditional compilation directives must be completed in the source or include
file in which they are begun.
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Directives #if, #elif, #else, and #endif
The conditional directives #if, #elif, #else, and #endif work very similar to
the common C conditional statements. If the expression you write after the #if
has a nonzero value, the line group immediately following the #if directive is
retained in the translation unit.
Syntax is:
#if constant_expression_1
<section_1>
[#elif constant_expression_2
<section_2>]
...
[#elif constant_expression_n
<section_n>]
[#else
<final_section>]
#endif
Each #if directive in a source file must be matched by a closing #endif directive. Any number of #elif directives can appear between the #if and #endif
directives, but at most one #else directive is allowed. The #else directive, if
present, must be the last directive before #endif.
The sections can be any program text that has meaning to the compiler or the preprocessor. The preprocessor selects a single section by evaluating the
constant_expression following each #if or #elif directive until it finds a
true (nonzero) constant expression. The constant_expressions are subject to
macro expansion.
If all occurrences of constant-expression are false, or if no #elif directives
appear, the preprocessor selects the text block after the #else clause. If the
#else clause is omitted and all instances of constant_expression in the #if
block are false, no section is selected for further processing.
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Any processed section can contain further conditional clauses, nested to any
depth. Each nested #else, #elif, or #endif directive belongs to the closest preceding #if directive.
The net result of the preceding scenario is that only one code section (possibly
empty) will be compiled.
Directives #ifdef and #ifndef
You can use the #ifdef and #ifndef directives anywhere #if can be used. The
#ifdef and #ifndef conditional directives let you test whether an identifier is
currently defined or not. The line
#ifdef identifier
has exactly the same effect as #if 1 if identifier is currently defined, and the
same effect as #if 0 if identifier is currently undefined. The other directive,
#ifndef, tests true for the “not-defined” condition, producing the opposite
results.
The syntax thereafter follows that of the #if, #elif, #else, and #endif.
An identifier defined as NULL is considered to be defined.
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CHAPTER
4
mikroC Libraries
mikroC provides a number of built-in and library routines which help you develop
your application faster and easier. Libraries for ADC, CAN, USART, SPI, I2C, 1Wire, LCD, PWM, RS485, Serial Ethernet, Toshiba GLCD, Port Expander, Serial
GLCD, numeric formatting, bit manipulation, and many other are included along
with practical, ready-to-use code examples.
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BUILT-IN ROUTINES
mikroC compiler provides a set of useful built-in utility functions. Built-in functions do not require any header files to be included; you can use them in any part
of your project.
Built-in routines are implemented as “inline”; i.e. code is generated in the place of
the call, so the call doesn’t count against the nested call limit. The only exceptions
are Vdelay_ms and Delay_Cyc, which are actual C routines.
Note: Lo, Hi, Higher and Highest functions are not implemented in compiler any
more. If you want to use these functions you must include built_in.h into your
project.
Lo
Hi
Higher
Highest
Delay_us
Delay_ms
Vdelay_ms
Delay_Cyc
Clock_Khz
Clock_Mhz
Lo
Prototype
unsigned short Lo(long number);
Returns
Returns the lowest 8 bits (byte) of number, bits 0..7.
Description
Function returns the lowest byte of number. Function does not interpret bit patterns of
number – it merely returns 8 bits as found in register.
This is an “inline” routine; code is generated in the place of the call, so the call doesn’t
count against the nested call limit.
Requires
Arguments must be scalar type (i.e. Arithmetic Types and Pointers).
Example
d = 0x1AC30F4;
tmp = Lo(d); // Equals 0xF4
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Hi
Prototype
unsigned short Hi(long number);
Returns
Returns next to the lowest byte of number, bits 8..15.
Description
Function returns next to the lowest byte of number. Function does not interpret bit patterns of number – it merely returns 8 bits as found in register.
This is an “inline” routine; code is generated in the place of the call, so the call doesn’t
count against the nested call limit.
Requires
Arguments must be scalar type (i.e. Arithmetic Types and Pointers).
Example
d = 0x1AC30F4;
tmp = Hi(d); // Equals 0x30
Higher
Prototype
unsigned short Higher(long number);
Returns
Returns next to the highest byte of number, bits 16..23.
Description
Function returns next to the highest byte of number. Function does not interpret bit patterns of number – it merely returns 8 bits as found in register.
This is an “inline” routine; code is generated in the place of the call, so the call doesn’t
count against the nested call limit.
Requires
Arguments must be scalar type (i.e. Arithmetic Types and Pointers).
Example
d = 0x1AC30F4;
tmp = Higher(d);
// Equals 0xAC
Highest
Prototype
unsigned short Highest(long number);
Returns
Returns the highest byte of number, bits 24..31.
Description
Function returns the highest byte of number. Function does not interpret bit patterns of
number – it merely returns 8 bits as found in register.
This is an “inline” routine; code is generated in the place of the call, so the call doesn’t
count against the nested call limit.
Requires
Arguments must be scalar type (i.e. Arithmetic Types and Pointers).
Example
d = 0x1AC30F4;
tmp = Highest(d);
// Equals 0x01
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Delay_us
Prototype
void Delay_us(const time_in_us);
Description
Creates a software delay in duration of time_in_us microseconds (a constant). Range
of applicable constants depends on the oscillator frequency.
Example
Delay_us(10);
/* Ten microseconds pause */
Delay_ms
Prototype
void Delay_ms(const time_in_ms);
Description
Creates a software delay in duration of time_in_ms milliseconds (a constant). Range of
applicable constants depends on the oscillator frequency.
Example
Delay_ms(1000);
/* One second pause */
Vdelay_ms
Prototype
void Vdelay_ms(unsigned time_in_ms);
Description
Creates a software delay in duration of time_in_ms milliseconds (a variable).
Generated delay is not as precise as the delay created by Delay_ms.
Example
pause = 1000;
// ...
Vdelay_ms(pause);
// ~ one second pause
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Delay_Cyc
Prototype
void Delay_Cyc(char Cycles_div_by_10);
Description
Creates a delay based on MCU clock. Delay lasts for 10 times the input parameter in
MCU cycles. Input parameter needs to be in range 3 .. 255.
Note that Delay_Cyc is library function rather than a built-in routine; it is presented in
this topic for the sake of convenience.
Example
Delay_Cyc(10);
/* Hundred MCU cycles pause */
Clock_Khz
Prototype
unsigned Clock_Khz(void);
Returns
Device clock in KHz, rounded to the nearest integer.
Description
Returns device clock in KHz, rounded to the nearest integer.
Example
clk = Clock_Khz();
Clock_Mhz
Prototype
unsigned Clock_Mhz(void);
Returns
Device clock in MHz, rounded to the nearest integer.
Description
Returns device clock in MHz, rounded to the nearest integer.
Example
clk = Clock_Mhz();
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LIBRARY ROUTINES
mikroC provides a set of libraries which simplifies the initialization and use of
PIC MCU and its modules. Library functions do not require any header files to be
included; you can use them anywhere in your projects.
Currently available libraries are:
Hardware/PIC-specific Libraries
- ADC Library
- CAN Library
- CANSPI Library
- Compact Flash Library
- EEPROM Library
- Ethernet Library
- SPI Ethernet Library
- Flash Memory Library
- Graphic LCD Library
- T6963C Graphic LCD Library
- I²C Library
- Keypad Library
- LCD Library
- LCD Custom Library
- LCD8 Library
- Manchester Code Library
- Multi Media Card Library
- OneWire Library
- PS/2 Library
- PWM Library
- RS-485 Library
- Software I²C Library
- Software SPI Library
- Software UART Library
- Sound Library
- SPI Library
- USART Library
- USB HID Library
- Util Library
- SPI Graphic LCD Library
- Port Expander Library
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Standard ANSI C Libraries
- ANSI C Ctype Library
- ANSI C Math Library
- ANSI C Stdlib Library
- ANSI C String Library
Miscellaneous Libraries
- Conversions Library
- Trigonometry Library
- sprint Library
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ADC Library
ADC (Analog to Digital Converter) module is available with a number of PIC
MCU models. Library function Adc_Read is included to provide you comfortable
work with the module.
Adc_Read
Prototype
unsigned Adc_Read(char channel);
Returns
10-bit unsigned value read from the specified ADC channel.
Description
Initializes PIC’s internal ADC module to work with RC clock. Clock determines the
time period necessary for performing AD conversion (min 12TAD).
Parameter channel represents the channel from which the analog value is to be
acquired. For channel-to-pin mapping please refer to documentation for the appropriate
PIC MCU.
Requires
PIC MCU with built-in ADC module. You should consult the Datasheet documentation
for specific device (most devices from PIC16/18 families have it).
Before using the function, be sure to configure the appropriate TRISA bits to designate
the pins as input. Also, configure the desired pin as analog input, and set Vref (voltage
reference value).
The function is currently unsupported by the following PICmicros: P18F2331,
P18F2431, P18F4331, and P18F4431.
Example
unsigned tmp;
...
tmp = Adc_Read(1);
/* read analog value from channel 1 */
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Library Example
/* This code snippet reads analog value from channel 2 and displays
it on PORTD (lower 8 bits) and PORTB (2 most significant bits). */
unsigned temp_res;
void main() {
ADCON1 = 0x80;
TRISA = 0xFF;
TRISB = 0x3F;
TRISD = 0;
//
//
//
//
Configure analog inputs and Vref
PORTA is input
Pins RB7, RB6 are outputs
PORTD is output
do {
temp_res = Adc_Read(2);
PORTD = temp_res;
PORTB = temp_res >> 2;
} while(1);
// Get results of AD conversion
// Send lower 8 bits to PORTD
// Send 2 most significant bits to RB7, RB6
}
Hardware Connection
VCC
RB7
4
RA2
11
12
13
14
VCC
GND
OSC1
OSC2
PIC18F452
VCC
RB6
RB5
RB4
RB3
RB2
RB1
RB0
40
39
38
37
36
35
34
33
330
LD0
330
LD1
330
LD2
330
LD3
330
LD4
330
LD5
330
LD6
330
LD7
10K
VCC
Reset
8MHz
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CAN Library
mikroC provides a library (driver) for working with the CAN module.
CAN is a very robust protocol that has error detection and signalling, self–checking and fault confinement. Faulty CAN data and remote frames are re-transmitted
automatically, similar to the Ethernet.
Data transfer rates vary from up to 1 Mbit/s at network lengths below 40m to 250
Kbit/s at 250m cables, and can go even lower at greater network distances, down
to 200Kbit/s, which is the minimum bitrate defined by the standard. Cables used
are shielded twisted pairs, and maximum cable length is 1000m.
CAN supports two message formats:
Standard format, with 11 identifier bits, and
Extended format, with 29 identifier bits
Note: CAN routines are currently supported only by P18XXX8 PICmicros.
Microcontroller must be connected to CAN transceiver (MCP2551 or similar)
which is connected to CAN bus.
Note: Be sure to check CAN constants necessary for using some of the functions.
See page 145.
Library Routines
CANSetOperationMode
CANGetOperationMode
CANInitialize
CANSetBaudRate
CANSetMask
CANSetFilter
CANRead
CANWrite
Following routines are for the internal use by compiler only:
RegsToCANID
CANIDToRegs
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CANSetOperationMode
Prototype
void CANSetOperationMode(char mode, char wait_flag);
Description
Sets CAN to requested mode, i.e. copies mode to CANSTAT. Parameter mode needs to
be one of CAN_OP_MODE constants (see CAN constants).
Parameter wait_flag needs to be either 0 or 0xFF:
If set to 0xFF, this is a blocking call – the function won’t “return” until the requested
mode is set. If 0, this is a non-blocking call. It does not verify if CAN module is
switched to requested mode or not. Caller must use function CANGetOperationMode
to verify correct operation mode before performing mode specific operation.
Requires
CAN routines are currently supported only by P18XXX8 PICmicros. Microcontroller
must be connected to CAN transceiver (MCP2551 or similar) which is connected to
CAN bus.
Example
CANSetOperationMode(CAN_MODE_CONFIG, 0xFF);
CANGetOperationMode
Prototype
char CANGetOperationMode(void);
Returns
Current opmode.
Description
Function returns current operational mode of CAN module.
Requires
CAN routines are currently supported only by P18XXX8 PICmicros. Microcontroller
must be connected to CAN transceiver (MCP2551 or similar) which is connected to
CAN bus.
Example
if (CANGetOperationMode() == CAN_MODE_NORMAL) { ... };
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CANInitialize
Prototype
void CANInitialize(char SJW, char BRP, char PHSEG1, char PHSEG2,
char PROPSEG, char CAN_CONFIG_FLAGS);
Description
Initializes CAN. All pending transmissions are aborted. Sets all mask registers to 0 to
allow all messages. The Config mode is internaly set by this function. Upon a execution
of this function Normal mode is set.
Filter registers are set according to flag value:
if (CAN_CONFIG_FLAGS & CAN_CONFIG_VALID_XTD_MSG != 0)
// Set all filters to XTD_MSG
else if (config & CONFIG_VALID_STD_MSG != 0)
// Set all filters to STD_MSG
else
// Set half the filters to STD, and the rest to XTD_MSG
Parameters:
SJW as defined in 18XXX8 datasheet (1–4)
BRP as defined in 18XXX8 datasheet (1–64)
PHSEG1 as defined in 18XXX8 datasheet (1–8)
PHSEG2 as defined in 18XXX8 datasheet (1–8)
PROPSEG as defined in 18XXX8 datasheet (1–8)
CAN_CONFIG_FLAGS is formed from predefined constants (see CAN constants).
Requires
CAN routines are currently supported only by P18XXX8 PICmicros. Microcontroller
must be connected to CAN transceiver (MCP2551 or similar) which is connected to
CAN bus.
Example
init = CAN_CONFIG_SAMPLE_THRICE
&
CAN_CONFIG_PHSEG2_PRG_ON
&
CAN_CONFIG_STD_MSG
&
CAN_CONFIG_DBL_BUFFER_ON
&
CAN_CONFIG_VALID_XTD_MSG
&
CAN_CONFIG_LINE_FILTER_OFF;
...
CANInitialize(1, 1, 3, 3, 1, init);
// initialize CAN
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CANSetBaudRate
Prototype
void CANSetBaudRate(char SJW, char BRP, char PHSEG1, char PHSEG2,
char PROPSEG, char CAN_CONFIG_FLAGS);
Description
Sets CAN baud rate. Due to complexity of CAN protocol, you cannot simply force a bps
value. Instead, use this function when CAN is in Config mode. Refer to datasheet for
details.
Parameters:
SJW as defined in 18XXX8 datasheet (1–4)
BRP as defined in 18XXX8 datasheet (1–64)
PHSEG1 as defined in 18XXX8 datasheet (1–8)
PHSEG2 as defined in 18XXX8 datasheet (1–8)
PROPSEG as defined in 18XXX8 datasheet (1–8)
CAN_CONFIG_FLAGS is formed from predefined constants (see CAN constants)
Requires
CAN must be in Config mode; otherwise the function will be ignored.
Example
init = CAN_CONFIG_SAMPLE_THRICE
&
CAN_CONFIG_PHSEG2_PRG_ON
&
CAN_CONFIG_STD_MSG
&
CAN_CONFIG_DBL_BUFFER_ON
&
CAN_CONFIG_VALID_XTD_MSG
&
CAN_CONFIG_LINE_FILTER_OFF;
...
CANSetBaudRate(1, 1, 3, 3, 1, init);
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CANSetMask
Prototype
void CANSetMask(char CAN_MASK, long value, char CAN_CONFIG_FLAGS);
Description
Function sets mask for advanced filtering of messages. Given value is bit adjusted to
appropriate buffer mask registers.
Parameters: CAN_MASK is one of predefined constant values (see CAN constants);
value is the mask register value; CAN_CONFIG_FLAGS selects type of message to filter,
either CAN_CONFIG_XTD_MSG or CAN_CONFIG_STD_MSG.
Requires
CAN must be in Config mode; otherwise the function will be ignored.
Example
// Set all mask bits to 1, i.e. all filtered bits are relevant:
CANSetMask(CAN_MASK_B1, -1, CAN_CONFIG_XTD_MSG);
/* Note that -1 is just a cheaper way to write 0xFFFFFFFF.
Complement will do the trick and fill it up with ones. */
CANSetFilter
Prototype
void CANSetFilter(char CAN_FILTER, long value,
char CAN_CONFIG_FLAGS);
Description
Function sets mask for advanced filtering of messages. Given value is bit adjusted to
appropriate buffer mask registers.
Parameters: CAN_MASK is one of predefined constant values (see CAN constants);
value is the filter register value; CAN_CONFIG_FLAGS selects type of message to filter,
either CAN_CONFIG_XTD_MSG or CAN_CONFIG_STD_MSG.
Requires
CAN must be in Config mode; otherwise the function will be ignored.
Example
/* Set id of filter B1_F1 to 3: */
CANSetFilter(CAN_FILTER_B1_F1, 3, CAN_CONFIG_XTD_MSG);
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CANRead
Prototype
char CANRead(long *id, char *data, char *datalen, char
*CAN_RX_MSG_FLAGS);
Returns
Message from receive buffer or zero if no message found.
Description
Function reads message from receive buffer. If at least one full receive buffer is found, it
is extracted and returned. If none found, function returns zero.
Parameters: id is message identifier; data is an array of bytes up to 8 bytes in length;
datalen is data length, from 1–8; CAN_RX_MSG_FLAGS is value formed from constants
(see CAN constants).
Requires
CAN must be in mode in which receiving is possible.
Example
char rcv, rx, len, data[8]; long id;
rcv = CANRead(id, data, len, 0);
CANWrite
Prototype
char CANWrite(long id, char *data, char datalen, char
CAN_TX_MSG_FLAGS);
Returns
Returns zero if message cannot be queued (buffer full).
Description
If at least one empty transmit buffer is found, function sends message on queue for
transmission. If buffer is full, function returns 0.
Parameters: id is CAN message identifier. Only 11 or 29 bits may be used depending
on message type (standard or extended); data is array of bytes up to 8 bytes in length;
datalen is data length from 1–8; CAN_TX_MSG_FLAGS is value formed from constants
(see CAN constants).
Requires
CAN must be in Normal mode.
Example
char tx, data; long id;
tx = CAN_TX_PRIORITY_0 & CAN_TX_XTD_FRAME;
CANWrite(id, data, 2, tx);
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CAN Constants
There is a number of constants predefined in CAN library. To be able to use the
library effectively, you need to be familiar with these. You might want to check
the example at the end of the chapter.
CAN_OP_MODE
CAN_OP_MODE constants define CAN operation mode. Function
CANSetOperationMode expects one of these as its argument:
#define
#define
#define
#define
#define
#define
CAN_MODE_BITS
CAN_MODE_NORMAL
CAN_MODE_SLEEP
CAN_MODE_LOOP
CAN_MODE_LISTEN
CAN_MODE_CONFIG
0xE0
0
0x20
0x40
0x60
0x80
// Use it to access mode bits
CAN_CONFIG_FLAGS
CAN_CONFIG_FLAGS constants define flags related to CAN module configuration.
Functions CANInitialize and CANSetBaudRate expect one of these (or a bitwise
combination) as their argument:
#define CAN_CONFIG_DEFAULT
0xFF
// 11111111
#define CAN_CONFIG_PHSEG2_PRG_BIT
#define CAN_CONFIG_PHSEG2_PRG_ON
#define CAN_CONFIG_PHSEG2_PRG_OFF
0x01
0xFF
0xFE
// XXXXXXX1
// XXXXXXX0
#define CAN_CONFIG_LINE_FILTER_BIT
#define CAN_CONFIG_LINE_FILTER_ON
#define CAN_CONFIG_LINE_FILTER_OFF
0x02
0xFF
0xFD
// XXXXXX1X
// XXXXXX0X
#define CAN_CONFIG_SAMPLE_BIT
#define CAN_CONFIG_SAMPLE_ONCE
#define CAN_CONFIG_SAMPLE_THRICE
0x04
0xFF
0xFB
// XXXXX1XX
// XXXXX0XX
#define CAN_CONFIG_MSG_TYPE_BIT
#define CAN_CONFIG_STD_MSG
#define CAN_CONFIG_XTD_MSG
0x08
0xFF
0xF7
// XXXX1XXX
// XXXX0XXX
// continues..
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// ..continued
#define CAN_CONFIG_DBL_BUFFER_BIT
#define CAN_CONFIG_DBL_BUFFER_ON
#define CAN_CONFIG_DBL_BUFFER_OFF
0x10
0xFF
0xEF
// XXX1XXXX
// XXX0XXXX
#define
#define
#define
#define
#define
0x60
0xFF
0xDF
0xBF
0x9F
//
//
//
//
CAN_CONFIG_MSG_BITS
CAN_CONFIG_ALL_MSG
CAN_CONFIG_VALID_XTD_MSG
CAN_CONFIG_VALID_STD_MSG
CAN_CONFIG_ALL_VALID_MSG
X11XXXXX
X10XXXXX
X01XXXXX
X00XXXXX
You may use bitwise AND (&) to form config byte out of these values. For example:
init = CAN_CONFIG_SAMPLE_THRICE & CAN_CONFIG_PHSEG2_PRG_ON &
CAN_CONFIG_STD_MSG
& CAN_CONFIG_DBL_BUFFER_ON &
CAN_CONFIG_VALID_XTD_MSG & CAN_CONFIG_LINE_FILTER_OFF;
//...
CANInitialize(1, 1, 3, 3, 1, init);
// initialize CAN
CAN_TX_MSG_FLAGS
CAN_TX_MSG_FLAGS
#define
#define
#define
#define
#define
are flags related to transmission of a CAN message:
CAN_TX_PRIORITY_BITS
CAN_TX_PRIORITY_0
CAN_TX_PRIORITY_1
CAN_TX_PRIORITY_2
CAN_TX_PRIORITY_3
0x03
0xFC
0xFD
0xFE
0xFF
//
//
//
//
#define CAN_TX_FRAME_BIT
#define CAN_TX_STD_FRAME
#define CAN_TX_XTD_FRAME
0x08
0xFF
0xF7
// XXXXX1XX
// XXXXX0XX
#define CAN_TX_RTR_BIT
#define CAN_TX_NO_RTR_FRAME
#define CAN_TX_RTR_FRAME
0x40
0xFF
0xBF
// X1XXXXXX
// X0XXXXXX
XXXXXX00
XXXXXX01
XXXXXX10
XXXXXX11
You may use bitwise AND (&) to adjust the appropriate flags. For example:
/* form value to be used with CANSendMessage: */
send_config = CAN_TX_PRIORITY_0 && CAN_TX_XTD_FRAME &
CAN_TX_NO_RTR_FRAME;
//...
CANSendMessage(id, data, 1, send_config);
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CAN_RX_MSG_FLAGS
are flags related to reception of CAN message. If a particular
bit is set; corresponding meaning is TRUE or else it will be FALSE.
CAN_RX_MSG_FLAGS
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
CAN_RX_FILTER_BITS
CAN_RX_FILTER_1
CAN_RX_FILTER_2
CAN_RX_FILTER_3
CAN_RX_FILTER_4
CAN_RX_FILTER_5
CAN_RX_FILTER_6
CAN_RX_OVERFLOW
CAN_RX_INVALID_MSG
CAN_RX_XTD_FRAME
CAN_RX_RTR_FRAME
CAN_RX_DBL_BUFFERED
0x07
0x00
0x01
0x02
0x03
0x04
0x05
0x08
0x10
0x20
0x40
0x80
// Use it to access filter bits
//
//
//
//
//
//
Set if Overflowed; else clear
Set if invalid; else clear
Set if XTD msg; else clear
Set if RTR msg; else clear
Set if msg was
hardware double-buffered
You may use bitwise AND (&) to adjust the appropriate flags. For example:
if (MsgFlag & CAN_RX_OVERFLOW != 0) {
... // Receiver overflow has occurred; previous message is lost.
}
CAN_MASK
CAN_MASK constants define mask codes. Function CANSetMask expects one of
these as its argument:
#define CAN_MASK_B1
#define CAN_MASK_B2
0
1
CAN_FILTER
CAN_FILTER constants define filter codes. Function CANSetFilter expects one of
these as its argument:
#define
#define
#define
#define
#define
#define
CAN_FILTER_B1_F1
CAN_FILTER_B1_F2
CAN_FILTER_B2_F1
CAN_FILTER_B2_F2
CAN_FILTER_B2_F3
CAN_FILTER_B2_F4
0
1
2
3
4
5
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Library Example
unsigned short aa, aa1, len, aa2;
unsigned char data[8];
long id;
unsigned short zr, cont, oldstate;
//........
void main() {
PORTC = 0;
TRISC = 0;
PORTD = 0;
TRISD = 0;
aa = 0;
aa1 = 0;
aa2 = 0;
// Form value to be used with CANSendMessage
aa1 = CAN_TX_PRIORITY_0 &
CAN_TX_XTD_FRAME &
CAN_TX_NO_RTR_FRAME;
// Form value to be used with CANInitialize
aa =
CAN_CONFIG_SAMPLE_THRICE
&
CAN_CONFIG_PHSEG2_PRG_ON
&
CAN_CONFIG_STD_MSG
&
CAN_CONFIG_DBL_BUFFER_ON
&
CAN_CONFIG_VALID_XTD_MSG
&
CAN_CONFIG_LINE_FILTER_OFF;
data[0] = 0;
// Initialize CAN
CANInitialize(1,1,3,3,1,aa);
// Set CAN to CONFIG mode
CANSetOperationMode(CAN_MODE_CONFIG,0xFF);
id = -1;
// continues ..
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// .. continued
// Set all mask1 bits to ones
CANSetMask(CAN_MASK_B1,ID,CAN_CONFIG_XTD_MSG);
// Set all mask2 bits to ones
CANSetMask(CAN_MASK_B2,ID,CAN_CONFIG_XTD_MSG);
// Set id of filter B1_F1 to 3
CANSetFilter(CAN_FILTER_B2_F3,3,CAN_CONFIG_XTD_MSG);
// Set CAN to NORMAL mode
CANSetOperationMode(CAN_MODE_NORMAL,0xFF);
PORTD = 0xFF;
id = 12111;
CANWrite(id,data,1,aa1);
// Send message via CAN
while (1) {
oldstate = 0;
zr = CANRead(&id, data , &len, &aa2);
if ((id == 3) & zr) {
PORTD = 0xAA;
PORTC = data[0];
data[0]++ ;
// Output data at PORTC
// If message contains two data bytes, output second byte at PORTD
if (len == 2) PORTD = data[1];
data[1] = 0xFF;
id = 12111;
CANWrite(id, data, 2,aa1);
// Send incremented data back
}
}
}//~!
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Hardware Connection
CAN TX of MCU
CAN RX of MCU
10
1
2
VCC
3
TX-CAN RS
GND CANH
8
7
6
VCC CANL
4
RXD
Vref
5
MCP2551
Shielded pair
no longer than 300m
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CANSPI Library
SPI module is available with a number of PICmicros. mikroC provides a library
(driver) for working with the external CAN modules (such as MCP2515 or
MCP2510) via SPI.
In mikroC, each routine of CAN library has its CANSPI counterpart with identical
syntax. For more information on the Controller Area Network, consult the CAN
Library. Note that the effective communication speed depends on the SPI, and is
certainly slower than the “real” CAN.
Note: CANSPI functions are supported by any PIC MCU that has SPI interface on
PORTC. Also, CS pin of MCP2510 or MCP2515 must be connected to RC0.
Example of HW connection is given at the end of the chapter.
Note: Be sure to check CAN constants necessary for using some of the functions.
See page 145.
Note: SPI_Init() must be called before initializing CANSPI.
Library Routines
CANSPISetOperationMode
CANSPIGetOperationMode
CANSPIInitialize
CANSPISetBaudRate
CANSPISetMask
CANSPISetFilter
CANSPIRead
CANSPIWrite
Following routines are for the internal use by compiler only:
RegsToCANSPIID
CANSPIIDToRegs
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CANSPISetOperationMode
Prototype
void CANSPISetOperationMode(char mode, char wait_flag);
Description
Sets CAN to requested mode, i.e. copies mode to CANSTAT. Parameter mode needs to
be one of CAN_OP_MODE constants (see CAN constants, page 145).
Parameter wait_flag needs to be either 0 or 0xFF: If set to 0xFF, this is a blocking
call – the function won’t “return” until the requested mode is set. If 0, this is a nonblocking call. It does not verify if CAN module is switched to requested mode or not.
Caller must use function CANSPIGetOperationMode to verify correct operation mode
before performing mode specific operation.
Requires
CANSPI functions are supported by any PIC MCU that has SPI interface on PORTC.
Also, CS pin of MCP2510 or MCP2515 must be connected to RC0.
Example
CANSPISetOperationMode(CAN_MODE_CONFIG, 0xFF);
CANSPIGetOperationMode
Prototype
char CANSPIGetOperationMode(void);
Returns
Current opmode.
Description
Function returns current operational mode of CAN module.
Example
if (CANSPIGetOperationMode() == CAN_MODE_NORMAL) { ... };
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CANSPIInitialize
Prototype
void CANSPIInitialize(char SJW, char BRP, char PHSEG1, char
PHSEG2, char PROPSEG, char CAN_CONFIG_FLAGS, char * RstPort, char
RstPin, char * CSPort, char CSPin);
Description
Initializes CANSPI. All pending transmissions are aborted. Sets all mask registers to 0
to allow all messages.
Filter registers are set according to flag value:
if (CAN_CONFIG_FLAGS & CAN_CONFIG_VALID_XTD_MSG != 0)
// Set all filters to XTD_MSG
else if (config & CONFIG_VALID_STD_MSG != 0)
// Set all filters to STD_MSG
else
// Set half the filters to STD, and the rest to XTD_MSG
Parameters:
SJW as defined in 18XXX8 datasheet (1–4)
BRP as defined in 18XXX8 datasheet (1–64)
PHSEG1 as defined in 18XXX8 datasheet (1–8)
PHSEG2 as defined in 18XXX8 datasheet (1–8)
PROPSEG as defined in 18XXX8 datasheet (1–8)
CAN_CONFIG_FLAGS is formed from predefined constants (see CAN constants, page
145).
Requires
SPI_Init() must be called before initializing CANSPI.
CANSPI must be in Config mode; otherwise the function will be ignored.
Example
init = CAN_CONFIG_SAMPLE_THRICE
&
CAN_CONFIG_PHSEG2_PRG_ON
&
CAN_CONFIG_STD_MSG
&
CAN_CONFIG_DBL_BUFFER_ON
&
CAN_CONFIG_VALID_XTD_MSG
&
CAN_CONFIG_LINE_FILTER_OFF;
...
// initialize external CAN module
CANSPIInitialize( 1,1,3,3,1,init, &PORTC, 2, &PORTC, 0);
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CANSPISetBaudRate
Prototype
void CANSPISetBaudRate(char SJW, char BRP, char PHSEG1, char
PHSEG2, char PROPSEG, char CAN_CONFIG_FLAGS);
Description
Sets CANSPI baud rate. Due to complexity of CANSPI protocol, you cannot simply
force a bps value. Instead, use this function when CANSPI is in Config mode. Refer to
datasheet for details.
Parameters:
SJW as defined in 18XXX8 datasheet (1–4)
BRP as defined in 18XXX8 datasheet (1–64)
PHSEG1 as defined in 18XXX8 datasheet (1–8)
PHSEG2 as defined in 18XXX8 datasheet (1–8)
PROPSEG as defined in 18XXX8 datasheet (1–8)
CAN_CONFIG_FLAGS is formed from predefined constants (see CAN constants)
Requires
CANSPI must be in Config mode; otherwise the function will be ignored.
Example
init = CAN_CONFIG_SAMPLE_THRICE
&
CAN_CONFIG_PHSEG2_PRG_ON
&
CAN_CONFIG_STD_MSG
&
CAN_CONFIG_DBL_BUFFER_ON
&
CAN_CONFIG_VALID_XTD_MSG
&
CAN_CONFIG_LINE_FILTER_OFF;
...
CANSPISetBaudRate(1, 1, 3, 3, 1, init);
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CANSPISetMask
Prototype
void CANSPISetMask(char CAN_MASK, long value, char
CAN_CONFIG_FLAGS);
Description
Function sets mask for advanced filtering of messages. Given value is bit adjusted to
appropriate buffer mask registers.
Parameters: CAN_MASK is one of predefined constant values (see CAN constants);
value is the mask register value; CAN_CONFIG_FLAGS selects type of message to filter,
either CAN_CONFIG_XTD_MSG or CAN_CONFIG_STD_MSG.
Requires
CANSPI must be in Config mode; otherwise the function will be ignored.
Example
// Set all mask bits to 1, i.e. all filtered bits are relevant:
CANSPISetMask(CAN_MASK_B1, -1, CAN_CONFIG_XTD_MSG);
/* Note that -1 is just a cheaper way to write 0xFFFFFFFF.
Complement will do the trick and fill it up with ones. */
CANSPISetFilter
Prototype
void CANSPISetFilter(char CAN_FILTER, long value,
char CAN_CONFIG_FLAGS);
Description
Function sets mask for advanced filtering of messages. Given value is bit adjusted to
appropriate buffer mask registers.
Parameters: CAN_MASK is one of predefined constant values (see CAN constants);
value is the filter register value; CAN_CONFIG_FLAGS selects type of message to filter,
either CAN_CONFIG_XTD_MSG or CAN_CONFIG_STD_MSG.
Requires
CANSPI must be in Config mode; otherwise the function will be ignored.
Example
/* Set id of filter B1_F1 to 3: */
CANSPISetFilter(CAN_FILTER_B1_F1, 3, CAN_CONFIG_XTD_MSG);
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CANSPIRead
Prototype
char CANSPIRead(long *id, char *data, char *datalen, char
*CAN_RX_MSG_FLAGS);
Returns
Message from receive buffer or zero if no message found.
Description
Function reads message from receive buffer. If at least one full receive buffer is found, it
is extracted and returned. If none found, function returns zero.
Parameters: id is message identifier; data is an array of bytes up to 8 bytes in length;
datalen is data length, from 1–8; CAN_RX_MSG_FLAGS is value formed from constants
(see CAN constants).
Requires
CANSPI must be in mode in which receiving is possible.
Example
char rcv, rx, len, data[8]; long id;
rcv = CANSPIRead(id, data, len, 0);
CANSPIWrite
Prototype
char CANSPIWrite(long id, char *data, char datalen, char
CAN_TX_MSG_FLAGS);
Returns
Returns zero if message cannot be queued (buffer full).
Description
If at least one empty transmit buffer is found, function sends message on queue for
transmission. If buffer is full, function returns 0.
Parameters: id is CANSPI message identifier. Only 11 or 29 bits may be used depending on message type (standard or extended); data is array of bytes up to 8 bytes in
length; datalen is data length from 1–8; CAN_TX_MSG_FLAGS is value formed from
constants (see CAN constants).
Requires
CANSPI must be in Normal mode.
Example
char tx, data; long id;
tx = CAN_TX_PRIORITY_0 & CAN_TX_XTD_FRAME;
CANSPIWrite(id, data, 2, tx);
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Library Example
The code is a simple demonstration of CANSPI protocol. It is a simple data exchange between 2
PIC’s, where data is incremented upon each bounce. Data is printed on PORTC (lower byte) and
PORTD (higher byte) for a visual check.
char data[8],aa, aa1, len, aa2;
long id;
char zr;
const char _TRUE = 0xFF;
const char _FALSE = 0x00;
void main(){
TRISB = 0;
Spi_Init();
TRISC.F2 = 0;
PORTC.F2 = 0;
PORTC.F0 = 1;
TRISC.F0 = 0;
PORTD = 0;
TRISD = 0;
aa
= 0;
aa1
= 0;
aa2
= 0;
//
//
//
//
//
Initialize SPI module
Clear (TRISC,2)
Clear (PORTC,2)
Set
(PORTC,0)
Clear (TRISC,0)
// Form value to be used with CANSPIInitialize
aa = CAN_CONFIG_SAMPLE_THRICE &
CAN_CONFIG_PHSEG2_PRG_ON &
CAN_CONFIG_STD_MSG
&
CAN_CONFIG_DBL_BUFFER_ON &
CAN_CONFIG_VALID_XTD_MSG;
PORTC.F2 = 1;
// Set (PORTC,2)
// Form value to be used with CANSPISendMessage
aa1 = CAN_TX_PRIORITY_0 &
CAN_TX_XTD_FRAME &
CAN_TX_NO_RTR_FRAME;
PORTC.F0 = 1;
// Set (PORTC,0)
// continues ..
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// .. continued
Spi_Init(); // Initialize SPI
// Initialize external CAN module
CANSPIInitialize( 1,1,3,3,1,aa, &PORTC, 2, &PORTC, 0);
// Set CANSPI to CONFIG mode
CANSPISetOperationMode(CAN_MODE_CONFIG,_TRUE);
ID = -1;
// Set all mask1 bits to ones
CANSPISetMask(CAN_MASK_B1,id,CAN_CONFIG_XTD_MSG);
// Set all mask2 bits to ones
CANSPISetMask(CAN_MASK_B2,id,CAN_CONFIG_XTD_MSG);
// Set id of filter B1_F1 to 12111
CANSPISetFilter(CAN_FILTER_B2_F4,12111,CAN_CONFIG_XTD_MSG);
// Set CANSPI to NORMAL mode
CANSPISetOperationMode(CAN_MODE_NORMAL,_TRUE);
while (1) {
zr = CANSPIRead(&id , &Data , &len, &aa2);
if (id == 12111 & zr ) {
PORTB = data[0]++ ;
id = 3;
Delay_ms(500);
// Receive data, if any
// Output data on PORTB
// Send incremented data back
CANSPIWrite(id,&data,1,aa1);
// If message contains 2 data bytes, output second byte at PORTD
if (len == 2) PORTD = data[1];
}
}
}//~!
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Hardware Connection
VCC
100K
VCC
1
2
4
5
6
7
Vdd
RX
RST
CLKO
CS
TX0
SO
TX1
SI
TX2
SCK
OSC2
8
9
17
16
15
14
VCC
13
12
11
11
12
INT
OSC1 RX0B
Vss
18
RX1B
13
10
14
8 MhZ
15
MCP2510
VCC
GND
OSC1
OSC2
RC0
PIC18F452
3
TX
RB0
8 MhZ
18
RC5
RC3
RC4
33
24
23
10
1
2
VCC
3
TX-CAN RS
GND CANH
8
7
6
VCC CANL
4
RXD
Vref
5
MCP2551
Shielded pair
no longer than 300m
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Compact Flash Library
Compact Flash Library provides routines for accessing data on Compact Flash
card (abbrev. CF further in text). CF cards are widely used memory elements,
commonly found in digital cameras. Great capacity (8MB ~ 2GB, and more) and
excellent access time of typically few microseconds make them very attractive for
microcontroller applications.
In CF card, data is divided into sectors, one sector usually comprising 512 bytes
(few older models have sectors of 256B). Read and write operations are not performed directly, but successively through 512B buffer. Following routines can be
used for CF with FAT16, and FAT32 file system. Note that routines for file handling can be used only with FAT16 file system.
Important! Before write operation, make sure you don’t overwrite boot or FAT
sector as it could make your card on PC or digital cam unreadable. Drive mapping
tools, such as Winhex, can be of a great assistance.
Library Routines
Cf_Init
Cf_Detect
Cf_Total_Size
Cf_Enable
Cf_Disable
Cf_Read_Init
Cf_Read_Byte
Cf_Write_Init
Cf_Write_Byte
Cf_Fat_Init
Cf_Fat_Assign
Cf_Fat_Reset
Cf_Fat_Read
Cf_Fat_Rewrite
Cf_Fat_Append
Cf_Fat_Delete
Cf_Fat_Write
Cf_Fat_Set_File_Date
Cf_Fat_Get_File_Date
Cf_Fat_Get_File_Size
Function Cf_Set_Reg_Adr is for compiler internal purpose only.
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Cf_Init
Prototype
void Cf_Init(char *ctrlport, char *dataport);
Description
Initializes ports appropriately for communication with CF card. Specify two different
ports: ctrlport and dataport.
Example
Cf_Init(&PORTB, &PORTD);
Cf_Detect
Prototype
char Cf_Detect(void);
Returns
Returns 1 if CF is present, otherwise returns 0.
Description
Checks for presence of CF card on ctrlport.
Example
// Wait until CF card is inserted:
do nop; while (Cf_Detect() == 0);
Cf_Total_Size
Prototype
unsigned long Cf_Total_Size(void);
Returns
Card size in kilobytes.
Description
Returns size of Compact Flash card in kilobytes.
Requires
Ports must be initialized. See Cf_Init.
Example
size = Cf_Total_Size();
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Cf_Enable
Prototype
void Cf_Enable(void);
Description
Enables the device. Routine needs to be called only if you have disabled the device by
means of Cf_Disable. These two routines in conjuction allow you to free/occupy data
line when working with multiple devices. Check the example at the end of the chapter.
Requires
Ports must be initialized. See Cf_Init.
Example
Cf_Enable();
Cf_Disable
Prototype
void Cf_Disable(void);
Description
Routine disables the device and frees the data line for other devices. To enable the
device again, call Cf_Enable. These two routines in conjuction allow you to free/occupy data line when working with multiple devices. Check the example at the end of the
chapter.
Requires
Ports must be initialized. See Cf_Init.
Example
Cf_Disable();
Cf_Read_Init
Prototype
void Cf_Read_Init(long address, char sectcnt);
Description
Initializes CF card for reading. Parameter address specifies sector address from where
data will be read, and sectcnt is the number of sectors prepared for reading operation.
Requires
Ports must be initialized. See Cf_Init.
Example
Cf_Read_Init(590, 1);
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Cf_Read_Byte
Prototype
char Cf_Read_Byte(void);
Returns
Returns byte from CF.
Description
Reads one byte from CF.
Requires
CF must be initialized for read operation. See Cf_Read_Init.
Example
PORTC = Cf_Read_Byte();
// Read byte and display it on PORTC
Cf_Write_Init
Prototype
void Cf_Write_Init(long address, char sectcnt);
Description
Initializes CF card for writing. Parameter address specifies sector address where data
will be stored, and sectcnt is total number of sectors prepared for write operation.
Requires
Ports must be initialized. See Cf_Init.
Example
Cf_Write_Init(590, 1);
Cf_Write_Byte
Prototype
void Cf_Write_Byte(char data);
Description
Writes one byte (data) to CF. All 512 bytes are transferred to a buffer.
Requires
CF must be initialized for write operation. See Cf_Write_Init.
Example
Cf_Write_Byte(100);
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Cf_Fat_Init
Prototype
void Cf_Fat_Init(unsigned short *control_port, unsigned short wr,
rd, a2, a1, a0, ry, ce, cd, unsigned short *data_port);
Description
Initializes ports appropriately for FAT operations with CF card. Specify two different
ports: ctrlport and dataport. wr, rd, a2, a1, a0, ry, ce and cd are pin nummbers on control
port.
Requires
Nothing.
Example
CF_Fat_Init(PORTD,6,5,2,1,0,7,3,4, PORTC);
Cf_Fat_Assign
Prototype
unsigned short Cf_Fat_Assign(char *filename, char create_file);
Returns
"1" is file is present(or file isn't present but new file is created), or "0" if file isn't present
and no new file is created.
Description
Assigns file for FAT operations. If file isn't present, function creates new file with given
filename. filename parameter is name of file (filename must be in format 8.3 UPPERCASE). create_file is a parameter for creating new files. if create_file if different from 0
then new file is created (if there is no file with given filename).
Requires
Ports must be initialized for FAT operations with CF. See Cf_Fat_Init.
Example
Cf_Fat_Assign('MIKROELE.TXT',1);
Cf_Fat_Reset
Prototype
void Cf_fat_Reset(unsigned long *size);
Returns
Size of file in bytes. Size is stored on address of input variable.
Description
Opens assigned file for reading.
Requires
Ports must be initialized for FAT operations with CF. See Cf_Fat_Init.
File must be assigned. See Cf_Fat_Assign.
Example
Cf_Fat_Reset(size);
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Cf_Fat_Read
Prototype
void Cf_Fat_Read(unsigned short *bdata);
Description
Reads data from file. bdata is data read from file.
Requires
Ports must be initialized for FAT operations with CF. See Cf_Fat_Init.
File must be assigned. See Cf_Fat_Assign.
File must be open for reading. See Cf_Fat_Reset.
Example
Cf_Fat_Read(character);
Cf_Fat_Rewrite
Prototype
void Cf_Fat_Rewrite();
Returns
Nothing.
Description
Rewrites assigned file.
Requires
Ports must be initialized for FAT operations with CF. See Cf_Fat_Init.
File must be assigned. See Cf_Fat_Assign.
Example
Cf_Fat_Rewrite;
Cf_Fat_Append
Prototype
void Cf_fat_Append();
Returns
Nothing.
Description
Opens file for writing. This procedure continues writing from the last byte in file.
Requires
Ports must be initialized for FAT operations with CF. See Cf_Fat_Init.
File must be assigned. See Cf_Fat_Assign.
Example
Cf_Fat_Append;
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Cf_Fat_Delete
Prototype
void Cf_Fat_Delete();
Description
Deletes file from CF.
Requires
Ports must be initialized for FAT operations with CF. See Cf_Fat_Init.
File must be assigned. See Cf_Fat_Assign.
Example
Cf_Fat_Delete;
Cf_Fat_Write
Prototype
void Cf_Fat_Write(char *fdata, unsigned data_len);
Returns
Nothing.
Description
Writes data to CF. fdata parameter is data written to CF. data_len number of bytes that
is written to CF.
Requires
Ports must be initialized for FAT operations with CF. See Cf_Fat_Init.
File must be assigned. See Cf_Fat_Assign.
File must be open for writing. See Cf_Fat_Rewrite or Cf_Fat_Append.
Example
Cf_Fat_Write(file_contents, 42); // write data to the assigned
file
Cf_Fat_Set_File_Date
Prototype
void Cf_fat_Set_File_Date(unsigned int year, unsigned short
month, unsigned short day, unsigned short hours, unsigned short
mins, unsigned short seconds);
Returns
Nothing.
Description
Sets time attributes of file.You can set file year, month, day. hours, mins, seconds.
Requires
Ports must be initialized for FAT operations with CF. See Cf_Fat_Init.
File must be assigned. See Cf_Fat_Assign.
File must be open for writing. See Cf_Fat_Rewrite or Cf_Fat_Append.
Example
Cf_Fat_Set_File_Date(2005,9,30,17,41,0);
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Cf_Fat_Get_File_Date
Prototype
void Cf_Fat_Get_File_Date(unsigned int *year, unsigned short
*month, unsigned short *day, unsigned short *hours, unsigned
short *mins);
Description
Reads time attributes of file.You can read file year, month, day. hours, mins.
Requires
Ports must be initialized for FAT operations with CF. See Cf_Fat_Init.
File must be assigned. See Cf_Fat_Assign.
Example
Cf_Fat_Get_File_Date(year, month, day, hours, mins);
Cf_Fat_Get_File_Size
Prototype
unsigned long Cf_fat_Get_File_Size();
Returns
Size of file in bytes.
Description
This function returns size of file in bytes.
Requires
Ports must be initialized for FAT operations with CF. See Cf_Fat_Init.
File must be assigned. See Cf_Fat_Assign.
Example
Cf_Fat_Get_File_Size;
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Library Example
The following example writes 512 bytes at sector no.590, and then reads the data and prints on
PORTC for a visual check.
unsigned i;
void main() {
TRISC = 0;
Cf_Init(&PORTB, &PORTD);
// PORTC is output
// Initialize ports
do nop;
while (!Cf_Detect());
// Wait until CF card is inserted
Delay_ms(500);
Cf_Write_Init(590, 1);
// Initialize write at sector address 590
// Write 512 bytes to sector (590)
for (i = 0; i < 512; i++) Cf_Write_Byte(i + 11);
PORTC = 0xFF;
Delay_ms(1000);
Cf_Read_Init(590, 1);
// Initialize read at sector address 590
// Read 512 bytes from sector (590)
for (i = 0; i < 512; i++) {
PORTC = Cf_Read_Byte();
// Read byte and display on PORTC
Delay_ms(1000);
}
}
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HW Connection
40
RB7
39
RB6
38
RB5
37
RB4
11
12
13
14
15
VCC
GND
OSC1
OSC2
RC0
PIC18F452
VCC
36
RB3
35
RB2
34
RB1
33
RB0
30
RD7
29
RD6
28
RD5
27
RD4
8 MhZ
19
20
RD0
RD3
RD1
RD2
22
21
VCC
RD7
RD6
RD5
50
25
49
24
48
23
47
22
46
21
45
20
44
19
43
18
42
17
41
16
40
15
39
14
38
13
37
12
36
11
35
10
34
9
33
8
32
7
31
6
30
5
29
4
28
3
27
2
26
1
RD4
RD3
RD2
RD1
RD0
RB7
RB6
RB5
RB4
RB3
RB2
Compact Flash
Card
RB1
RB0
R25
10K
VCC
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Compact Flash FAT Library v2.xx
This is Compact Flash FAT library from previous version (v2.1). This library is included
because of users that have developed projects with old CF library.
NOTE
This version of Compact Flash FAT library is deprecated. There will be no longer development for this version of library. Please use new version of Compact Flash library for your
projects.
Important! File accessing routines can write file. File names must be exactly 8 characters
long and written in uppercase. User must ensure different names for each file, as CF routines will not check for possible match.
Important! Before write operation, make sure you don’t overwrite boot or FAT sector as it
could make your card on PC or digital cam unreadable. Drive mapping tools, such as
Winhex, can be of a great assistance.
Library Routines
Cf_Find_File
Cf_File_Write_Init
Cf_File_Write_Byte
Cf_Read_Sector
Cf_Write_Sector
Cf_Set_File_Date
Cf_File_Write_Complete
Cf_Find_File
Prototype
void Cf_Find_File(unsigned short find_first, char *file_name);
Description
Routine looks for files on CF card. Parameter find_first can be non-zero or zero; if nonzero, routine looks for the first file on card, in order of physical writing. Otherwise, routine “moves forward” to the next file from the current position, again in physical order.
If file is found, routine writes its name and extension in the string file_name. If no file is
found, the string will be filled with zeroes.
Requires
Ports must be initialized.
Example
Cf_Find_File(1, file);
if (file[0]) {
...// if first file found, handle it}
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Cf_File_Write_Init
Prototype
void Cf_File_Write_Init(void);
Description
Initializes CF card for file writing operation (FAT16 only).
Requires
Ports must be initialized. See Cf_Init.
Example
Cf_File_Write_Init();
Cf_File_Write_Byte
Prototype
void Cf_File_Write_Byte(char data);
Description
Adds one byte (data) to file. You can supply ASCII value as parameter, for example 48
for zero.
Requires
CF must be initialized for file write operation. See Cf_File_Write_Init.
Example
// Write 50,000 zeroes (bytes) to file:
for (i = 0; i < 50000; i++) Cf_File_Write_Byte(48);
Cf_Read_Sector
Prototype
void Cf_Read_Sector(int sector_number, unsigned short *buffer);
Description
Reads one sector (sector_number) into buffer.
Requires
CF must be initialized for file write operation. See Cf_Init.
Example
Cf_Read_Sector(22, data);
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Cf_Write_Sector
Prototype
void Cf_Write_Sector(int sector_number, unsigned short *buffer);
Description
Writes value from buffer to CF sector at sector_number.
Requires
CF must be initialized for file write operation. See Cf_Init.
Example
Cf_Write_Sector(22, data);
Cf_Set_File_Date
Prototype
void Cf_Set_File_Date(int year, char month,day,hours,min,sec);
Description
Writes system timestamp to a file. Use this routine before finalizing a file; otherwise,
file will be appended a random timestamp.
Requires
CF must be initialized for file write operation. See Cf_File_Write_Init.
Example
// April 1st 2005, 18:07:00
Cf_Set_File_Date(2005,4,1,18,7,0);
Cf_File_Write_Complete
Prototype
void Cf_File_Write_Complete(char filename[8], char *extension);
Description
Finalizes writing to file. Upon all data has be written to file, use this function to close
the file and make it readable. Parameter filename must be 8 chars long in uppercase.
Requires
CF must be initialized for file write operation. See Cf_File_Write_Init.
Example
Cf_File_Write_Complete("MY_FILE1","txt");
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EEPROM Library
EEPROM data memory is available with a number of PICmicros. mikroC includes
library for comfortable work with EEPROM.
Library Routines
Eeprom_Read
Eeprom_Write
Eeprom_Read
Prototype
char Eeprom_Read(char address);
Returns
Returns byte from the specified address.
Description
Reads data from the specified address. Parameter address is of byte type, which means
it can address only 256 locations. For PIC18 micros with more EEPROM data locations,
it is programmer’s responsibility to set SFR EEADRH register appropriately.
Requires
Requires EEPROM module.
Ensure minimum 20ms delay between successive use of routines Eeprom_Write and
Eeprom_Read. Although PIC will write the correct value, Eeprom_Read might return
an undefined result.
Example
char take;
...
take = Eeprom_Read(0x3F);
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Eeprom_Read
Prototype
void Eeprom_Write(char address, char data);
Description
Writes data to the specified address. Parameter address is of byte type, which means it
can address only 256 locations. For PIC18 micros with more EEPROM data locations, it
is programmer’s responsibility to set SFR EEADRH register appropriately.
Be aware that all interrupts will be disabled during execution of EEPROM_Write routine (GIE bit of INTCON register will be cleared). Routine will set this bit on exit.
Requires
Requires EEPROM module.
Ensure minimum 20ms delay between successive use of routines Eeprom_Write and
Eeprom_Read. Although PIC will write the correct value, Eeprom_Read might return
an undefined result.
Example
Eeprom_Write(0x32);
Library Example
unsigned short i = 0, j = 0;
void main() {
PORTB = 0;
TRISB = 0;
j = 4;
for (i = 0; i < 20u; i++)
Eeprom_Write(i, j++);
for (i = 0; i < 20u; i++) {
PORTB = Eeprom_Read(i);
Delay_ms(500);
}
}//~!
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Ethernet Library
This library is designed to simplify handling of the underlying hardware
(RTL8019AS). However, certain level of knowledge about the Ethernet and
Ethernet-based protocols (ARP, IP, TCP/IP, UDP/IP, ICMP/IP) is expected from
the user. The Ethernet is a high–speed and versatile protocol, but it is not a simple
one. Once you get used to it, however, you will make your favorite PIC available
to a much broader audience than you could do with the RS232/485 or CAN.
Library Routines
Eth_Init
Eth_Set_Ip_Address
Eth_Inport
Eth_Scan_For_Event
Eth_Get_Ip_Hdr_Len
Eth_Load_Ip_Packet
Eth_Get_Hdr_Chksum
Eth_Get_Source_Ip_Address
Eth_Get_Dest_Ip_Address
Eth_Arp_Response
Eth_Get_Icmp_Info
Eth_Ping_Response
Eth_Get_Udp_Source_Port
Eth_Get_Udp_Dest_Port
Eth_Get_Udp_Port
Eth_Set_Udp_Port
Eth_Send_Udp
Eth_Load_Tcp_Header
Eth_Get_Tcp_Hdr_Offset
Eth_Get_Tcp_Flags
Eth_Set_Tcp_Data
Eth_Tcp_Response
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Eth_Init
Prototype
void Eth_Init(char *addrP, char *dataP, char *ctrlP,
char pinReset, char pinIOW, char pinIOR);
Description
Performs initialization of Ethernet card and library. This includes:
- Setting of control and data ports;
- Initialization of the Ethernet card (also called the Network Interface Card, or NIC);
- Retrieval and local storage of the NIC’s hardware (MAC) address;
- Putting the NIC into the LISTEN mode.
Parameter addrP is a pointer to address port, which handles the addressing lines.
Parameter dataP is pointer to data port. Parameter ctrlP is the control port. Parameter
pinReset is the reset/enable pin for the ethernet card chip (on control port). Parameter
pinIOW is the I/O Write request control pin. Parameter pinIOR is the I/O read request
control pin.
Requires
As specified for the entire library (please see top of this page).
Example
Eth_Init(&PORTB, &PORTD, &PORTE, 2, 1, 0);
Eth_Set_Ip_Address
Prototype
void Eth_Set_Ip_Address(char ip1, char ip2, char ip3, char ip4);
Description
Sets the IP address of the connected and initialized Ethernet network card. The
arguments are the IP address numbers, in IPv4 format (e.g. 127.0.0.1).
Requires
This function should be called immediately after the NIC initialization (see Eth_Init).
You can change your IP address at any time, anywhere in the code.
Example
// Set IP address 192.168.20.25
Eth_Set_Ip_Address(192u, 168u, 20u, 25u);
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Eth_Set_Inport
Prototype
unsigned short Eth_Inport(unsigned short address);
Returns
One byte from the specified address.
Description
Retrieves a byte from the specified address of the Ethernet card chip.
Requires
The card (NIC) must be properly initialized. See Eth_Init.
Example
udp_length |= Eth_Inport(NIC_DATA);
Eth_Scan_For_Event
Prototype
unsigned Eth_Scan_For_Event(unsigned short *next_ptr);
Returns
Type of the ethernet packet received. Two types are distinguished: ARP (MAC-IP
address data request) and IP (Internet Protocol).
Description
Retrieves sender’s MAC (hardware) address and type of the packet received. The
function argument is an (internal) pointer to the next data packet in RTL8019’s buffer,
and is of no particular importance to the end user.
Requires
The card (NIC) must be properly initialized. See Eth_Init. Also, the function must be
called in a proper sequence, i.e. right after the card init, and IP address/UDP port init.
Example
Eth_Init(&PORTB, &PORTD, &PORTE, 2, 1, 0);
Eth_Set_Ip_Address(192u, 168u, 20u, 25u);
Eth_Set_Udp_Port(10001);
do { // Main block of every Ethernet example
event_type = Eth_Scan_For_Event(&next_ptr);
if (event_type) {
switch (event_type) {case ARP: Arp_Event(); break;
case IP : Ip_Event();}
Eth_Outport(CR, 0x22);
Eth_Outport(BNDRY, next_ptr);
}
} while (1);
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Eth_Get_Ip_Hdr_Len
Prototype
unsigned short Eth_Get_Ip_Hdr_Len(void);
Returns
Header length of the received IP packet.
Description
Returns header length of the received IP packet. Before other data based upon the IP
protocol (TCP, UDP, ICMP) can be analyzed, the sub-protocol data must be properly
loaded from the received IP packet.
Requires
The card (NIC) must be properly initialized. See Eth_Init. The function must be
called in a proper sequence, i.e. immediately after determining that the packet received
is the IP packet.
Example
// Receive IP Header
opt_len = Eth_Get_Ip_Hdr_Len() - 20;
Eth_Load_Ip_Packet
Prototype
void Eth_Load_Ip_Packet(void);
Description
Loads various IP packet data into PIC’s Ethernet variables.
Requires
The card (NIC) must be properly initialized. See Eth_Init. Also, a proper sequence of
calls must be obeyed (see the Ip_Event function in the supplied Ethernet example).
Example
Eth_Load_Ip_Packet();
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Eth_Get_Hdr_Chksum
Prototype
void Eth_Get_Hdr_Chksum(void);
Description
Loads and returns the header checksum of the received IP packet.
Requires
The card (NIC) must be properly initialized. See Eth_Init. Also, a proper sequence of
calls must be obeyed (see the Ip_Event function in the supplied Ethernet example).
Example
Eth_Get_Hdr_Chksum();
Eth_Get_Source_Ip_Address
Prototype
void Eth_Get_Source_Ip_Address(void);
Description
Loads and returns the IP address of the sender of the received IP packet.
Requires
The card (NIC) must be properly initialized. See Eth_Init. Also, a proper sequence of
calls must be obeyed (see the Ip_Event function in the supplied Ethernet example).
Example
Eth_Get_Source_Ip_Address();
Eth_Get_Dest_Ip_Address
Prototype
void Eth_Get_Dest_Ip_Address(void);
Description
Loads the IP address of the received IP packet for which the packet is designated.
Requires
The card (NIC) must be properly initialized. See Eth_Init. Also, a proper sequence of
calls must be obeyed (see the Ip_Event function in the supplied Ethernet example).
Example
Eth_Get_Dest_Ip_Address();
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Eth_Arp_Response
Prototype
void Eth_Arp_Response(void);
Description
An automated ARP response. User should simply call this function once he detects the
ARP event on the NIC.
Requires
As specified for the entire library.
Example
Eth_Arp_Response();
Eth_Get_Icmp_Info
Prototype
void Eth_Get_Icmp_Info(void);
Description
Loads ICMP protocol information (from the header of the received ICMP packet) and
stores it to the PIC’s Ethernet variables.
Requires
The card (NIC) must be properly initialized. See Eth_Init. Also, this function must be
called in a proper sequence, and before the Eth_Ping_Response.
Example
Eth_Get_Icmp_Info();
Eth_Ping_Response
Prototype
void Eth_Ping_Response(void);
Description
An automated ICMP (Ping) response. User should call this function when answerring to
an ICMP/IP event.
Requires
As specified for the entire library.
Example
Eth_Ping_Response();
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Eth_Get_Udp_Source_Port
Prototype
unsigned Eth_Get_Udp_Source_Port(void);
Returns
Returns the source port (socket) of the received UDP packet.
Description
The function returns the source port (socket) of the received UDP packet. After the
reception of valid IP packet is detected and its type is determined to be UDP, the UDP
packet header must be interpreted. UDP source port is the first data in the UDP header.
Requires
This function must be called in a proper sequence, i.e. immediately after interpretation
of the IP packet header (at the very beginning of UDP packet header retrieval).
Example
udp_source_port = Eth_Get_Udp_Source_Port();
Eth_Get_Udp_Dest_Port
Prototype
unsigned Eth_Get_Udp_Dest_Port(void);
Returns
Returns the destination port of the received UDP packet.
Description
The function returns the destination port of the received UDP packet. The second
information contained in the UDP packet header is the destination port (socket) to which
the packet is targeted.
Requires
This function must be called in a proper sequence, i.e. immediately after calling the
Eth_Get_Udp_Source_Port function.
Example
udp_dest_port = Eth_Get_Udp_Dest_Port();
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Eth_Get_Udp_Port
Prototype
unsigned short Eth_Get_Udp_Port(void);
Returns
Returns the UDP port (socket) number that is set for the PIC’s Ethernet card.
Description
The function returns the UDP port (socket) number that is set for the PIC's Ethernet
card. After the UDP port is set at the beginning of the session (Eth_Set_Udp_Port), its
number is later used to test whether the received UDP packet is targeted at the port we
are using.
Requires
The network card must be properly initialized (see Eth_Init), and the UDP port
propely set (see Eth_Set_Udp_Port). This library currently supports working with
only one UDP port (socket) at a time.
Example
if (udp_dest_port == Eth_Get_Udp_Port()) {
... // Respond to action
}
Eth_Set_Udp_Port
Prototype
void Eth_Set_Udp_Port(unsigned udp_port);
Description
Sets up the default UDP port, which will handle user requests. The user can decide,
upon receiving the UDP packet, which port was this packet sent to, and whether it will
be handled or rejected.
Requires
As specified for the entire library.
Example
Eth_Set_Udp_Port(10001);
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Eth_Send_Udp
Prototype
void Eth_Send_Udp(char *msg);
Description
Sends the prepared UDP message (msg), of up to 16 bytes (characters).
Unlike ICMP and TCP, the UDP packets are generally not generated as a response to the
client request. UDP provides no guarantees for message delivery and sender retains no
state on UDP messages once sent onto the network. This is why UDP packets are simply
sent, instead of being a response to someone’s request.
Requires
As specified for the entire library. Also, the message to be sent must be formatted as a
null-terminated string. The message length, including the trailing “0”, must not exceed
16 characters.
Example
Eth_Send_Udp(udp_tx_message);
Eth_Load_Tcp_Header
Prototype
void Eth_Load_Tcp_Header(void);
Description
Loads various TCP Header data into PIC’s Ethernet variables.
Requires
This function must be called in a proper sequence, i.e. immediately after retrieving the
source and destination port (socket) of the TCP message.
Example
// retrieve 'source port'
tcp_source_port = Eth_Inport(NIC_DATA) << 8;
tcp_source_port |= Eth_Inport(NIC_DATA);
// retrieve 'destination port'
tcp_dest_port = Eth_Inport(NIC_DATA) << 8;
tcp_dest_port |= Eth_Inport(NIC_DATA);
// We only respond to port 80 (HTML requests)
if (tcp_dest_port == 80u) {
Eth_Load_Tcp_Header(); // retrieve TCP Header data (most of it)
//...
}
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Eth_Get_Tcp_Hdr_Offset
Prototype
unsigned short Eth_Get_Tcp_Hdr_Offset(void);
Returns
Returns the length (or offset) of the TCP packet header in bytes.
Description
The function returns the length (or offset) of the TCP packet header in bytes. Upon
receiving a valid TCP packet, its header is to be analyzed in order to respond properly
(e.g. respond to other's request, merge several packets into the message, etc.). The header length is important to know in order to be able to extract the information contained in
it.
Requires
This function must be called after the Eth_Load_Tcp_Header, since it initializes the
private variables used for this function.
Example
// calculate offset (TCP header length)
tcp_options = Eth_Get_Tcp_Hdr_Offset() - 20;
Eth_Get_Tcp_Flags
Prototype
unsigned short Eth_Get_Tcp_Flags(void);
Returns
Returns the flags data from the header of the received TCP packet.
Description
The function returns the flags data from the header of the received TCP packet. TCP
flags show various information, e.g. SYN (syncronize request), ACK (acknowledge
receipt), and similar. It is upon these flags that, for example, a proper HTTP communication is established.
Requires
This function must be called after the Eth_Load_Tcp_Header, since it initializes the
private variables used for this function.
Example
flags = Eth_Get_Tcp_Flags();
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Eth_Set_Tcp_Data
Prototype
void Eth_Set_Tcp_Data(const unsigned short *data);
Description
Prepares data to be sent on HTTP request. This library can handle only HTTP requests,
so sending other TCP-based protocols, such as FTP, will cause an error. Note that
TCP/IP was not designed with 8-bit MCU’s in mind, so be gentle with your HTTP
requests.
Requires
As specified for the entire library.
Example
// Let's prepare a simple HTML page in our string:
const char httpPage1[] =
"HTTP/1.0 200 OK\nContent-type: text/html\n"
"<html>\n" "<body>\n"
"<h1>Hello world!</h1>\n"
"</body>\n" "</html>";
//...
Eth_Set_Tcp_Data(httpPage1);
//...
Eth_Tcp_Response
Prototype
void Eth_Tcp_Response(void);
Description
Performs user response to TCP/IP event. User specifies data to be sent, depending on the
request received (HTTP, HTTPD, FTP, etc). This is performed by the function
Eth_Set_Tcp_Data.
Requires
Hardware requirements are as specified for the entire library. Prior to using this function, user must prepare the data to be sent through TCP; see Eth_Set_Tcp_Data.
Example
Eth_Tcp_Response();
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Library Example
Check the supplied Ethernet example in the Examples folder.
200
+5V
1K
8
9
1K
7
10
6
11
3
14
2
15
1
16
0.1u
+5V
+5V
0.1u
0.1u
0.1u
BD3
BD2
GND
BD1
BD0
GND
SD15
SD14
Vdd
SD13
SD12
SD11
SD10
SD9
SD8
IOCS16B
INT7
INT6
INT5
INT4
OSCI
TX+
TXVdd
LD
HD
GND
SD7
SD6
SD5
SD4
SD3
SD2
SD1
SD0
IOCHRDY
AEN
RSTDRV
SMEMWB
SMEMRB
RTL8019AS
U5
J2
0.1u
2KV
0.1u
2KV
20MHz
RD7
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
RD6
RD5
RD4
RD3
RD2
RD1
RD0
+5V
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
INT3
INT2
INT1
INT0
SA0
Vdd
SA1
SA2
SA3
SA4
SA5
SA6
SA7
GND
SA8
SA9
Vdd
SA10
AS11
SA12
SA13
SA14
SA15
SA16
SA17
SA18
SA19
GND
IORB
IOWB
+5V
BD4
BD5
BD6
BD7
EECS
BCSB
BA14
BA15
BA16
BA17
Vdd
BA18
BA19
BA20
BA21
JP
AUI
LED2
LED1
LED0
LEDBNC
TPIN+
TPINVdd
RX+
RXCD+
CDGND
OSCO
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
0.1u
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
8
7
6
5
4
3
2
1
T1 : FL1012
1K
RJ45
HW Connection
+5V
1K
RES
IOW
0.1u
IOR
RB4
RB3
RB2
RB1
RB0
+5V
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SPI Ethernet Library
The ENC28J60 is a stand-alone Ethernet controller with an industry standard
Serial Peripheral Interface (SPI™). It is designed to serve as an Ethernet network
interface for any controller equipped with SPI.
The ENC28J60 meets all of the IEEE 802.3 specifications. It incorporates a number of packet filtering schemes to limit incoming packets. It also provides an internal DMA module for fast data throughput and hardware assisted IP checksum calculations. Communication with the host controller is implemented via two interrupt pins and the SPI, with data rates of up to 10 Mb/s. Two dedicated pins are
used for LED link and network activity indication.
This library is designed to simplify handling of the underlying hardware
(ENC28J60). It works with any PIC with integrated SPI and more than 4 Kb ROM
memory. 38 to 40 MHz clock is recommended to get from 8 to 10 Mhz SPI clock,
otherwise PIC should be clocked by ENC clock output due to ENC silicon bug in
SPI hardware. if you try lower PIC clock speed, there might be board hang or miss
some requests. This library is tested with [email protected],
[email protected]
Note: For advanced users there is a header in Uses\P16 and Uses\P18 folder
("enc28j60_libprivate.h") with detailed description of all functions which are
implemented in SPI Ethernet Library.
Note: SPI_Init() must be called before initializing SPI Ethernet.
Library Routines
SPI_Ethernet_Init
SPI_Ethernet_doPacket
SPI_Ethernet_putByte
SPI_Ethernet_getByte
SPI_Ethernet_UserTCP
SPI_Ethernet_UserUDP
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SPI_Ethernet_Init
Prototype
void SPI_Ethernet_Init(unsigned char *resetPort, unsigned char
resetBit, unsigned char *CSportPtr, unsigned char CSbit, unsigned
char *mac, unsigned char *ip, unsigned char fullDuplex);
Returns
Nothing.
Description
Initialize SPI & ENC controller. This function is splited into 2 parts to help linker when
coming short of memory.
resetPort - pointer to reset pin port
resetBit - reset bit number on resetPort
CSport - pointer to CS pin port
CSbit - CS bit number on CSport
mac - pointer to array of 6 char with MAC address
ip - pointer to array of 4 char with IP address
fullDuplex - either SPI_Ethernet_HALFDUPLEX for half duplex or
SPI_Ethernet_FULLDUPLEX for full duplex
Requires
SPI_Init() must be called before initializing SPI Ethernet.
Example
SPI_Ethernet_Init(&PORTC, 0, &PORTC, 1, myMacAddr, myIpAddr,
SPI_Ethernet_FULLDUPLEX);
SPI_Ethernet_doPacket
Prototype
void SPI_Ethernet_doPacket();
Returns
Nothing.
Description
Process one incoming packet if available. This function is public.
Requires
SPI_Ethernet_init must have been called before this function must be called as often as
possible by use.
Example
SPI_Ethernet_doPacket();
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SPI_Ethernet_putByte
Prototype
void SPI_Ethernet_putByte(unsigned char v);
Returns
Nothing.
Description
v - value to store
Store one byte to current EWRPT ENC location this function is public.
Requires
SPI_Ethernet_init must have been called before calling this function.
Example
SPI_Ethernet_putByte(0xa0);
SPI_Ethernet_getByte
Prototype
unsigned char SPI_Ethernet_getByte();
Returns
Value of byte @ addr.
Description
Get next byte from current ERDPT ENC location this function is public.
Requires
SPI_Ethernet_init must have been called before calling this function.
Example
b = SPI_Ethernet_getByte();
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SPI_Ethernet_UserTCP
Prototype
unsigned int SPI_Ethernet_UserTCP(unsigned char *remoteHost,
unsigned int remotePort, unsigned int localPort, unsigned int
reqLength);
Returns
Returns the length in bytes of the HTTP reply, or 0 if nothing to transmit.
Description
This function is called by the library. The user accesses to the HTTP request by successive calls to SPI_Ethernet_getByte() the user puts data in the transmit buffer by successive calls to SPI_Ethernet_putByte() the function must return the length in bytes of the
HTTP reply, or 0 if nothing to transmit. If you don't need to reply to HTTP requests, just
define this function with a return(0) as single statement.
Requires
SPI_Ethernet_init must have been called before calling this function.
Example
SPI_Ethernet_UserUDP
Prototype
unsigned int SPI_Ethernet_UserUDP(unsigned char *remoteHost,
unsigned int remotePort, unsigned int destPort, unsigned int
reqLength);
Returns
Returns the length in bytes of the UDP reply, or 0 if nothing to transmit.
Description
This function is called by the library. The user accesses to the UDP request by successive calls to SPI_Ethernet_getByte(). The user puts data in the transmit buffer by successive calls to SPI_Ethernet_putByte(). The function must return the length in bytes of the
UDP reply, or 0 if nothing to transmit. If you don't need to reply to UDP requests,just
define this function with a return(0) as single statement.
Requires
SPI_Ethernet_init must have been called before calling this function.
Example
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Library Example
The following example is a simple demonstration of the SPI Ethernet Library. PIC
is assigned an IP address of 192.168.20.60, and will respond to ping if connected
to a local area network.
#define SPI_Ethernet_HALFDUPLEX
#define SPI_Ethernet_FULLDUPLEX
0
1
/************************************************************
* ROM constant strings
*/
const unsigned char httpHeader[] = "HTTP/1.1 200 OK\nContent-type: " ; // HTTP header
const unsigned char httpMimeTypeHTML[] = "text/html\n\n" ;
// HTML MIME type
const unsigned char httpMimeTypeScript[] = "text/plain\n\n" ;
// TEXT MIME type
unsigned char httpMethod[] = "GET /";
/*
* web page, splited into 2 parts :
* when coming short of ROM, fragmented data is handled more efficiently by linker
*
* this HTML page calls the boards to get its status, and builds itself with
javascript
*/
const char
*indexPage = "<HTML><HEAD></HEAD><BODY>\
<h1>PIC + ENC28J60 Mini Web Server</h1>\
<a href=/>Reload</a>\
<script src=/s></script>\
<table><tr><td valign=top><table border=1 style=\"font-size:20px ;font-family: terminal ;\">\
<tr><th colspan=2>ADC</th></tr>\
<tr><td>AN2</td><td><script>document.write(AN2)</script></td></tr>\
<tr><td>AN3</td><td><script>document.write(AN3)</script></td></tr>\
</table></td><td><table border=1 style=\"font-size:20px ;font-family: terminal ;\">\
<tr><th colspan=2>PORTB</th></tr>\
<script>\
var str,i;\
str=\"\";\
for(i=0;i<8;i++)\
{str+=\"<tr><td bgcolor=pink>BUTTON #\"+i+\"</td>\";\
if(PORTB&(1<<i)){str+=\"<td bgcolor=red>ON\";}\
else {str+=\"<td bgcolor=#cccccc>OFF\";}\
str+=\"</td></tr>\";}\
document.write(str) ;\
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mikroC - C Compiler for Microchip PIC microcontrollers
</script>\
" ;
const char
*indexPage2 = "</table></td><td>\
<table border=1 style=\"font-size:20px ;font-family: terminal ;\">\
<tr><th colspan=3>PORTD</th></tr>\
<script>\
var str,i;\
str=\"\";\
for(i=0;i<8;i++)\
{str+=\"<tr><td bgcolor=yellow>LED #\"+i+\"</td>\";\
if(PORTD&(1<<i)){str+=\"<td bgcolor=red>ON\";}\
else {str+=\"<td bgcolor=#cccccc>OFF\";}\
str+=\"</td><td><a href=/t\"+i+\">Toggle</a></td></tr>\";}\
document.write(str) ;\
</script>\
</table></td></tr></table>\
This is HTTP request #<script>document.write(REQ)</script></BODY></HTML>\
" ;
//
str+=\"</td><td><a
href=/t\"+i+\">Toggle</a></td></tr>\";}\
/***********************************
* RAM variables
*/
unsigned char
myMacAddr[6] = {0x00, 0x14, 0xA5, 0x76, 0x19, 0x3f} ;//my MAC address
unsigned char
myIpAddr[4] = {192, 168, 20, 60} ;
// my IP address
unsigned char
getRequest[15] ;
// HTTP request buffer
unsigned char
dyna[31] ;
// buffer for dynamic response
unsigned long
httpCounter = 0 ;
// counter of HTTP requests
/*******************************************
* functions
*/
/*
* put the constant string pointed to by s to the ENC transmit buffer
*/
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unsigned int
putConstString(const char *s)
{
unsigned int ctr = 0 ;
while(*s)
{
SPI_Ethernet_putByte(*s++) ;
ctr++ ;
}
return(ctr) ;
}
/*
* put the string pointed to by s to the ENC transmit buffer
*/
unsigned int
putString(char *s)
{
unsigned int ctr = 0 ;
while(*s)
{
SPI_Ethernet_putByte(*s++) ;
ctr++ ;
}
return(ctr) ;
}
/*
* this function is called by the library
* the user accesses to the HTTP request by successive calls to
* SPI_Ethernet_getByte()
* the user puts data in the transmit buffer by successive calls to
* SPI_Ethernet_putByte()
* the function must return the length in bytes of the HTTP reply, or 0 if nothing
* to transmit
*
* if you don't need to reply to HTTP requests,
* just define this function with a return(0) as single statement
*
*/
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unsigned int
SPI_Ethernet_UserTCP(unsigned char *remoteHost, unsigned int
remotePort, unsigned int localPort, unsigned int reqLength)
{
unsigned int
len = 0 ;
// my reply length
unsigned int
i ;
// general purpose integer
if(localPort != 80)
{
return(0) ;
}
// I listen only to web request on port 80
// get 10 first bytes only of the request, the rest does not matter here
for(i = 0 ; i < 10 ; i++)
{
getRequest[i] = SPI_Ethernet_getByte() ;
}
getRequest[i] = 0 ;
if(memcmp(getRequest, httpMethod, 5))
{
return(0) ;
}
httpCounter++ ;
// only GET method is supported here
// one more request done
if(getRequest[5] == 's')
// if request path name starts with s, store dynamic data in transmit buffer
{
// the text string replied by this request can be interpreted as javascript
// statements by browsers
len = putConstString(httpHeader) ;
len += putConstString(httpMimeTypeScript) ;
// HTTP header
// with text MIME type
// add AN2 value to reply
intToStr(ADC_Read(2), dyna) ;
len += putConstString("var AN2=") ;
len += putString(dyna) ;
len += putConstString(";");
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// add AN3 value to reply
intToStr(ADC_Read(3), dyna) ;
len += putConstString("var AN3=") ;
len += putString(dyna) ;
len += putConstString(";") ;
// add PORTB value (buttons) to reply
len += putConstString("var PORTB=") ;
intToStr(PORTB, dyna) ;
len += putString(dyna) ;
len += putConstString(";") ;
// add PORTD value (LEDs) to reply
len += putConstString("var PORTD=") ;
intToStr(PORTD, dyna) ;
len += putString(dyna) ;
len += putConstString(";") ;
// add HTTP requests counter to reply
intToStr(httpCounter, dyna) ;
len += putConstString("var REQ=") ;
len += putString(dyna) ;
len += putConstString(";") ;
}
else if(getRequest[5] == 't')
// if request path name starts with t, toggle PORTD (LED) bit number that comes after
{
unsigned char
bitMask = 0 ;
// for bit mask
if(isdigit(getRequest[6]))
// if 0 <= bit number <= 9, bits 8 & 9 does not exist but does not matter
{
bitMask = getRequest[6] - '0' ; // convert ASCII to integer
bitMask = 1 << bitMask ;
// create bit mask
PORTD ^= bitMask ;
// toggle PORTD with xor operator
}
}
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if(len == 0)
{
len
len
len
len
}
mikroC - C Compiler for Microchip PIC microcontrollers
// what do to by default
=
+=
+=
+=
putConstString(httpHeader) ;
putConstString(httpMimeTypeHTML) ;
putConstString(indexPage) ;
putConstString(indexPage2) ;
//
//
//
//
HTTP
with
HTML
HTML
header
HTML MIME type
page first part
page second part
return(len) ; // return to the library with the number of bytes to transmit
}
/*
* this function is called by the library
* the user accesses to the UDP request by successive calls to SPI_Ethernet_getByte()
* the user puts data in the transmit buffer by successive calls to
* SPI_Ethernet_putByte()
* the function must return the length in bytes of the UDP reply, or 0 if nothing to
* transmit
*
* if you don't need to reply to UDP requests,
* just define this function with a return(0) as single statement
*
*/
unsigned int SPI_Ethernet_UserUDP(unsigned char *remoteHost, unsigned int remotePort,
unsigned int destPort, unsigned int reqLength)
{
unsigned int
len ;
// my reply length
unsigned char
*ptr ;
// pointer to the dynamic buffer
// reply is made of the
byteToStr(remoteHost[0],
dyna[3] = '.' ;
byteToStr(remoteHost[1],
dyna[7] = '.' ;
byteToStr(remoteHost[2],
dyna[11] = '.' ;
byteToStr(remoteHost[3],
remote host IP address in human readable format
dyna) ;
// first IP address byte
dyna + 4) ;
// second
dyna + 8) ;
// third
dyna + 12) ;
// fourth
dyna[15] = ':' ;
// add separator
// then remote host port number
intToStr(remotePort, dyna + 16) ;
dyna[22] = '[' ;
intToStr(destPort, dyna + 23) ;
dyna[29] = ']' ;
dyna[30] = 0 ;
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// the total length of the request is the length of the dynamic string plus the text
// of the request
len = 30 + reqLength ;
// puts the dynamic string into the transmit buffer
ptr = dyna ;
while(*ptr)
{
SPI_Ethernet_putByte(*ptr++) ;
}
// then puts the request string converted into upper char into the transmit buffer
while(reqLength--)
{
SPI_Ethernet_putByte(toupper(ENC28J60_getByte())) ;
}
return(len) ;
}
// back to the library with the length of the UDP reply
/*
* main entry
*/
void
main()
{
ADCON1 = 0x00 ;
PORTA = 0 ;
TRISA = 0xff ;
PORTB = 0 ;
TRISB = 0xff ;
PORTD = 0 ;
TRISD = 0 ;
/* starts ENC28J60 with
* reset bit on RC0
* CS bit on RC1
* my MAC & IP address
* full duplex
*/
Spi_Init();
// Initialize SPI
// ADC convertors will be used
// set PORTA as input for ADC
// set PORTB as input for buttons
// set PORTD as output
:
module
SPI_Ethernet_Init(&PORTC, 0, &PORTC, 1, myMacAddr, myIpAddr, SPI_Ethernet_FULLDUPLEX);
while(1)
// do forever
{
SPI_Ethernet_doPacket() ;
// process incoming Ethernet packets
/*
* add your stuff here if needed
* SPI_Ethernet_doPacket() must be called as often as possible
* otherwise packets could be lost
*/
}
}
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HW Connection
11
12
13
14
15
16
8 Mhz
18
VCC
GND
OSC1
OSC2
RC0
RC1
PIC18F452
VCC
RC5
RC3
RC4
24
23
LD2
LED
VCC
LD3
LED
VCC3
E3
10uF
ENC28J60
1
3
4
1B
1Y
2A
5
6
2B
2Y
7
GND
74HCT08N
2
1A
VCC
4B
4A
4Y
3B
3A
14
3
13
4
12
GND
LEDA
CLKOUT
LEDB
INT
5
11
3B
10
RC5
9
8
RC4
3Y
6
7
RC3
8
RC1
9
RC0
VCC
VCAP
2
1
10
WOL
OSC2
SO
OSC1
OSCGND
SCK
PLL-GND
CS
PLL-VCC
TPIN-
13
14
R3
500
27
26
25
24
23
21
25 MHz
20
19
RX-VCC
GND-RX TX-GND
12
R2
500
22
SI
RESET
11
OSC-VCC
28
TPOUT+
18
17
R4
51
16
TPIN+
TPOUT-
RBIAS
TX-VCC
15
R5
51
R1
2K
VCC3
R6
51
L1
FERRITE
BEAD
12 11
K2 A2
TD+
CT
TDRD+
K1 A1
10
9
R7
51
RJ45
CT
RD-
1
3
2
7
6
8
C4
100nF
C3
10nF
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Flash Memory Library
This library provides routines for accessing microcontroller Flash memory. Note
that prototypes differ for PIC16 and PIC18 families.
Library Routines
Flash_Read
Flash_Write
Flash_Read
Prototype
unsigned Flash_Read(unsigned address); // for PIC16
char Flash_Read(long unsigned address); // for PIC18
Returns
Returns data byte from Flash memory.
Description
Reads data from the specified address in Flash memory.
Example
Flash_Read(0x0D00);
Flash_Write
Prototype
void Flash_Write(unsigned address, unsigned data);
// for PIC16
void Flash_Write(unsigned long address, char *data); // for PIC18
Description
Writes chunk of data to Flash memory. With PIC18, data needs to be exactly 64 bytes in
size. Keep in mind that this function erases target memory before writing Data to it.
This means that if write was unsuccessful, previous data will be lost.
Example
// Write consecutive values in 64 consecutive locations
char toWrite[64];
// initialize array:
for (i = 0; i < 63; i++) toWrite[i] = i;
Flash_Write(0x0D00, toWrite);
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Library Example
The example demonstrates simple data exchange via USART. When PIC MCU
receives data, it immediately sends the same data back. If PIC is connected to the
PC (see the figure below), you can test the example from mikroC terminal for
RS232 communication, menu choice Tools > Terminal.
char i = 0, j = 0;
long addr;
unsigned short dataRd;
unsigned short dataWr[64] =
{1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,
1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,
1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,
1,2,3,4};
void main() {
PORTB = 0;
TRISB = 0;
PORTC = 0;
TRISC = 0;
addr = 0x00000A30;
Flash_Write(addr, dataWr);
// valid for P18F452
addr = 0x00000A30;
for (i = 0; i < 64; i++) {
dataRd = Flash_Read(addr++);
PORTB = dataRd;
Delay_ms(500);
}
}//~!
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I2C Library
I²C full master MSSP module is available with a number of PIC MCU models.
mikroC provides library which supports the master I²C mode.
Note: Certain PICmicros with two I²C modules, such as P18F8722, require you to
specify the module you want to use. Simply append the number 1 or 2 to a I2C.
For example, I2C2_Wr(); Also, for the sake of backward compabitility with previous compiler versions and easier code management, MCU's with multiple I2C
modules have I²C library which is identical to I2C1 (i.e. you can use I2C_Init()
instead of I2C1_Init() for I²C operations).
Library Routines
I2C_Init
I2C_Start
I2C_Repeated_Start
I2C_Is_Idle
I2C_Rd
I2C_Wr
I2C_Stop
I2C_Init
Prototype
void I2C_Init(long clock);
Description
Initializes I²C with desired clock (refer to device data sheet for correct values in
respect with Fosc). Needs to be called before using other functions of I2C Library.
Requires
Library requires MSSP module on PORTB or PORTC.
Example
I2C_Init(100000);
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I2C_Start
Prototype
char I2C_Start(void);
Returns
If there is no error, function returns 0.
Description
Determines if I²C bus is free and issues START signal.
Requires
I²C must be configured before using this function. See I2C_Init.
Example
I2C_Start();
I2C_Repeated_Start
Prototype
void I2C_Repeated_Start(void);
Description
Issues repeated START signal.
Requires
I²C must be configured before using this function. See I2C_Init.
Example
I2C_Repeated_Start();
I2C_Is_Idle
Prototype
char I2C_Is_Idle(void);
Returns
Returns 1 if I²C bus is free, otherwise returns 0.
Description
Tests if I²C bus is free.
Requires
I²C must be configured before using this function. See I2C_Init.
Example
if (I2C_Is_Idle()) {...}
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I2C_Rd
Prototype
char I2C_Rd(char ack);
Returns
Returns one byte from the slave.
Description
Reads one byte from the slave, and sends not acknowledge signal if parameter ack is 0,
otherwise it sends acknowledge.
Requires
START signal needs to be issued in order to use this function. See I2C_Start.
Example
temp = I2C_Rd(0); // Read data and send not acknowledge signal
I2C_Wr
Prototype
char I2C_Wr(char data);
Returns
Returns 0 if there were no errors.
Description
Sends data byte (parameter data) via I²C bus.
Requires
START signal needs to be issued in order to use this function. See I2C_Start.
Example
I2C_Write(0xA3);
I2C_Stop
Prototype
void I2C_Stop(void);
Description
Issues STOP signal.
Requires
I²C must be configured before using this function. See I2C_Init.
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Library Example
This code demonstrates use of I²C Library functions. PIC MCU is connected
(SCL, SDA pins ) to 24c02 EEPROM. Program sends data to EEPROM (data is
written at address 2). Then, we read data via I2C from EEPROM and send its
value to PORTD, to check if the cycle was successful (see the figure below how to
interface 24c02 to PIC).
void main(){
PORTB = 0;
TRISB = 0;
I2C_Init(100000);
I2C_Start();
I2C_Wr(0xA2);
I2C_Wr(2);
I2C_Wr(0xF0);
I2C_Stop();
//
//
//
//
Issue I2C
Send byte
Send byte
Send data
start signal
via I2C (command to 24cO2)
(address of EEPROM location)
(data to be written)
//
//
//
//
//
//
Issue I2C start signal
Send byte via I2C (device address + W)
Send byte (data address)
Issue I2C signal repeated start
Send byte (device address + R)
Read the data (NO acknowledge)
Delay_ms(100);
I2C_Start();
I2C_Wr(0xA2);
I2C_Wr(2);
I2C_Repeated_Start();
I2C_Wr(0xA3);
PORTB = I2C_Rd(0u);
I2C_Stop();
}
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mikroC
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mikroC - C Compiler for Microchip PIC microcontrollers
HW Connection
VCC
VCC
1
11
12
VCC
GND
13
14
OSC1
OSC2
PIC18F452
3
18
10K
4
10K
VCC
2
A0
Vcc
A1
WP
NC
SCL
GND
SDA
8
7
6
5
24C02
23
RC3
RC4
8 Mhz
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Keypad Library
mikroC provides library for working with 4x4 keypad; routines can also be used
with 4x1, 4x2, or 4x3 keypad. Check the connection scheme at the end of the
topic.
Library Routines
Keypad_Init
Keypad_Read
Keypad_Released
Keypad_Init
Prototype
void Keypad_Init(char *port);
Description
Initializes port to work with keypad. The function needs to be called before using other
routines of the Keypad library.
Example
Keypad_Init(&PORTB);
Keypad_Read
Prototype
unsigned Keypad_Read(void);
Returns
1..16, depending on the key pressed, or 0 if no key is pressed.
Description
Checks if any key is pressed. Function returns 1 to 16, depending on the key pressed, or
0 if no key is pressed.
Requires
Port needs to be appropriately initialized; see Keypad_Init.
Example
kp = Keypad_Read();
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Keypad_Released
Prototype
unsigned Keypad_Released(void);
Returns
1..16, depending on the key.
Description
Call to Keypad_Released is a blocking call: function waits until any key is pressed
and released. When released, function returns 1 to 16, depending on the key.
Requires
Port needs to be appropriately initialized; see Keypad_Init.
Example
kp = Keypad_Released();
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Library Example
The following code can be used for testing the keypad. It supports keypads with 1 to 4 rows and 1
to 4 columns. The code returned by the keypad functions (1..16) is transformed into ASCII codes
[0..9,A..F]. In addition, a small single-byte counter displays the total number of keys pressed in
the second LCD row.
unsigned short kp, cnt;
char txt[5];
void main() {
cnt = 0;
Keypad_Init(&PORTC);
Lcd_Init(&PORTB);
Lcd_Cmd(LCD_CLEAR);
Lcd_Cmd(LCD_CURSOR_OFF);
// Initialize LCD on PORTC
// Clear display
// Cursor off
Lcd_Out(1, 1, "Key :");
Lcd_Out(2, 1, "Times:");
do {
kp = 0;
//--- Wait for key to be pressed
do
//--- un-comment one of the keypad reading functions
kp = Keypad_Released();
//kp = Keypad_Read();
while (!kp);
cnt++;
//--- prepare value for output
if (kp > 10)
kp += 54;
else
kp += 47;
//--- print it
Lcd_Chr(1, 10,
WordToStr(cnt,
Lcd_Out(2, 10,
on LCD
kp);
txt);
txt);
} while (1);
}//~!
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HW Connection
RB7
RB6
RB5
RB4
11
12
VCC
GND
13
14
OSC1
OSC2
PIC18F452
VCC
RB3
RB2
RB1
RB0
40
39
38
1
2
3
A
4
5
6
B
7
8
9
C
*
0
#
D
37
36
35
34
33
KEYPAD
4X4
8 Mhz
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LCD Library (4-bit interface)
mikroC provides a library for communicating with commonly used LCD (4-bit
interface). Figures showing HW connection of PIC and LCD are given at the end
of the chapter.
Note: Be sure to designate port with LCD as output, before using any of the following library functions.
Library Routines
Lcd_Config
Lcd_Init
Lcd_Out
Lcd_Out_Cp
Lcd_Chr
Lcd_Chr_Cp
Lcd_Cmd
Lcd_Config
Prototype
void Lcd_Config(char *port, char RS, char EN, char WR, char D7,
char D6, char D5, char D4);
Description
Initializes LCD at port with pin settings you specify: parameters RS, EN, WR, D7 .. D4
need to be a combination of values 0–7 (e.g. 3,6,0,7,2,1,4).
Example
Lcd_Config(&PORTD,1,2,0,3,5,4,6);
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Lcd_Init
Prototype
void Lcd_Init(char *port);
Description
Initializes LCD at port with default pin settings (see the connection scheme at the end
of the chapter): D7 -> PORT.7, D6 -> PORT.6, D5 -> PORT.5, D4 -> PORT.4,
E -> PORT.3, RS -> PORT.2.
Example
Lcd_Init(&PORTB);
Lcd_Out
Prototype
void Lcd_Out(char row, char col, char *text);
Description
Prints text on LCD at specified row and column (parameter row and col). Both string
variables and literals can be passed as text.
Requires
Port with LCD must be initialized. See Lcd_Config or Lcd_Init.
Example
Lcd_Out(1, 3, "Hello!"); // Print "Hello!" at line 1, char 3
Lcd_Out_Cp
Prototype
void Lcd_Out_Cp(char *text);
Description
Prints text on LCD at current cursor position. Both string variables and literals can be
passed as text.
Requires
Port with LCD must be initialized. See Lcd_Config or Lcd_Init.
Example
Lcd_Out_Cp("Here!"); // Print "Here!" at current cursor position
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Lcd_Chr
Prototype
void Lcd_Chr(char row, char col, char character);
Description
Prints character on LCD at specified row and column (parameters row and col).
Both variables and literals can be passed as character.
Requires
Port with LCD must be initialized. See Lcd_Config or Lcd_Init.
Example
Lcd_Out(2, 3, 'i');
// Print 'i' at line 2, char 3
Lcd_Chr_Cp
Prototype
void Lcd_Chr_Cp(char character);
Description
Prints character on LCD at current cursor position. Both variables and literals can be
passed as character.
Requires
Port with LCD must be initialized. See Lcd_Config or Lcd_Init.
Example
Lcd_Out_Cp('e');
// Print 'e' at current cursor position
Lcd_Cmd
Prototype
void Lcd_Cmd(char command);
Description
Sends command to LCD. You can pass one of the predefined constants to the function.
The complete list of available commands is shown on the following page.
Requires
Port with LCD must be initialized. See Lcd_Config or Lcd_Init.
Example
Lcd_Cmd(Lcd_Clear);
// Clear LCD display
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LCD Commands
LCD Command
Purpose
LCD_FIRST_ROW
Move cursor to 1st row
LCD_SECOND_ROW
Move cursor to 2nd row
LCD_THIRD_ROW
Move cursor to 3rd row
LCD_FOURTH_ROW
Move cursor to 4th row
LCD_CLEAR
Clear display
LCD_RETURN_HOME
Return cursor to home position, returns a shifted display to original position. Display data RAM is unaffected.
LCD_CURSOR_OFF
Turn off cursor
LCD_UNDERLINE_ON
Underline cursor on
LCD_BLINK_CURSOR_ON
Blink cursor on
LCD_MOVE_CURSOR_LEFT
Move cursor left without changing display data RAM
LCD_MOVE_CURSOR_RIGHT
Move cursor right without changing display data RAM
LCD_TURN_ON
Turn LCD display on
LCD_TURN_OFF
Turn LCD display off
LCD_SHIFT_LEFT
Shift display left without changing display data RAM
LCD_SHIFT_RIGHT
Shift display right without changing display data RAM
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Library Example (default pin settings)
char *text = "mikroElektronika";
void main() {
TRISB = 0;
Lcd_Init(&PORTB);
Lcd_Cmd(Lcd_CLEAR);
Lcd_Cmd(Lcd_CURSOR_OFF);
Lcd_Out(1, 1, text);
}//~!
//
//
//
//
//
PORTB is output
Initialize LCD connected to PORTB
Clear display
Turn cursor off
Print text to LCD, 2nd row, 1st column
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RC6
RC5
RC4
RD3
RD2
RC1
RC2
RC3
RD0
RD1
RC7
RD5
RD4
RD7
RD6
VSS
VDD
RB1
RB0
RB2
RB3
RB5
RB4
RB7
RB6
VCC
Hardware Connection
RC0
14
8 MhZ
OSC1
OSC2
VSS
VDD
RE2
RE1
RE0
RA5
RA4
RA3
RA2
RA1
RA0
MCLR
PICxxxx
1
P4
5K
VCC
Contrast
Adjustment
GND
VCC
VEE
RS
R/W
E
D0
D1
D2
D3
D4
D5
D6
D7
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LCD Custom Library (4-bit interface)
mikroC provides a library for communicating with commonly used LCD (4-bit
interface). Figures showing custom HW connection of PIC and LCD are given at
the end of the chapter.
Note: Be sure to designate port with LCD as output, before using any of the following library functions.
Library Routines
Lcd_Custom_Config
Lcd_Custom_Out
Lcd_Custom_Out_Cp
Lcd_Custom_Chr
Lcd_Custom_Chr_Cp
Lcd_Custom_Cmd
Lcd_Custom_Config
Prototype
void Lcd_Custom_Config(char * data_port, char D7, char D6, char
D5, char D4, char * ctrl_port, char RS, char WR, char EN);
Description
Initializes LCD data port and control port with pin settings you specify.
Example
Lcd_Custom_Config(&PORTD,3,2,1,0,&PORTB,2,3,4);
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Lcd_Custom_Out
Prototype
void Lcd_Custom_Out(char row, char col, char *text);
Description
Prints text on LCD at specified row and column (parameter row and col). Both string
variables and literals can be passed as text.
Requires
Port with LCD must be initialized. See Lcd_Config.
Example
Lcd_Custom_Out(1, 3, "Hello!");//Print "Hello!" at line 1, char 3
Lcd_Custom_Out_Cp
Prototype
void Lcd_Custom_Out_Cp(char *text);
Description
Prints text on LCD at current cursor position. Both string variables and literals can be
passed as text.
Requires
Port with LCD must be initialized. See Lcd_Config.
Example
Lcd_Custom_Out_Cp("Here!"); // Print "Here!" at current cursor
position
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Lcd_Custom_Chr
Prototype
void Lcd_Custom_Chr(char row, char col, char character);
Description
Prints character on LCD at specified row and column (parameters row and col).
Both variables and literals can be passed as character.
Requires
Port with LCD must be initialized. See Lcd_Config.
Example
Lcd_Custom_Chr(2, 3, 'i');
// Print 'i' at line 2, char 3
Lcd_Custom_Chr_Cp
Prototype
void Lcd_Custom_Chr_Cp(char character);
Description
Prints character on LCD at current cursor position. Both variables and literals can be
passed as character.
Requires
Port with LCD must be initialized. See Lcd_Config.
Example
Lcd_Custom_Out_Cp('e');
// Print 'e' at current cursor position
Lcd_Custom_Cmd
Prototype
void Lcd_Custom_Cmd(char command);
Description
Sends command to LCD. You can pass one of the predefined constants to the function.
The complete list of available commands is shown on the following page.
Requires
Port with LCD must be initialized. See Lcd_Config.
Example
Lcd_Custom_Cmd(Lcd_Clear);
// Clear LCD display
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LCD Commands
LCD Command
Purpose
LCD_FIRST_ROW
Move cursor to 1st row
LCD_SECOND_ROW
Move cursor to 2nd row
LCD_THIRD_ROW
Move cursor to 3rd row
LCD_FOURTH_ROW
Move cursor to 4th row
LCD_CLEAR
Clear display
LCD_RETURN_HOME
Return cursor to home position, returns a shifted display to original position. Display data RAM is unaffected.
LCD_CURSOR_OFF
Turn off cursor
LCD_UNDERLINE_ON
Underline cursor on
LCD_BLINK_CURSOR_ON
Blink cursor on
LCD_MOVE_CURSOR_LEFT
Move cursor left without changing display data RAM
LCD_MOVE_CURSOR_RIGHT
Move cursor right without changing display data RAM
LCD_TURN_ON
Turn LCD display on
LCD_TURN_OFF
Turn LCD display off
LCD_SHIFT_LEFT
Shift display left without changing display data RAM
LCD_SHIFT_RIGHT
Shift display right without changing display data RAM
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Library Example (default pin settings)
char *text = "mikroElektronika";
void main() {
TRISB = 0;
// PORTB is output
Lcd_Custom_Config(&PORTB,7,6,5,4,&PORTB,3,0,2);// Initialize LCD connected to
PORTB
Lcd_Custom_Cmd(Lcd_CLEAR);
// Clear display
Lcd_Custom_Cmd(Lcd_CURSOR_OFF);
// Turn cursor off
Lcd_Custom_Out(1, 1, text);
// Print text to LCD, 2nd row, 1st column
}//~!
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RC6
RC5
RC4
RD3
RD2
RC1
RC2
RC3
RD0
RD1
RC7
RD5
RD4
RD7
RD6
VSS
VDD
RB1
RB0
RB2
RB3
RB5
RB4
RB7
RB6
VCC
Hardware Connection
RC0
14
8 MhZ
OSC1
OSC2
VSS
VDD
RE2
RE1
RE0
RA5
RA4
RA3
RA2
RA1
RA0
MCLR
PICxxxx
1
P4
5K
VCC
Contrast
Adjustment
GND
VCC
VEE
RS
R/W
E
D0
D1
D2
D3
D4
D5
D6
D7
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LCD8 Library (8-bit interface)
mikroC provides a library for communicating with commonly used 8-bit interface
LCD (with Hitachi HD44780 controller). Figures showing HW connection of PIC
and LCD are given at the end of the chapter.
Note: Be sure to designate Control and Data ports with LCD as output, before
using any of the following functions.
Library Routines
Lcd8_Config
Lcd8_Init
Lcd8_Out
Lcd8_Out_Cp
Lcd8_Chr
Lcd8_Chr_Cp
Lcd8_Cmd
Lcd8_Config
Prototype
void Lcd8_Config(char *ctrlport, char *dataport, char RS,
char EN, char WR, char D7, char D6, char D5, char D4, char D3,
char D2, char D1, char D0);
Description
Initializes LCD at Control port (ctrlport) and Data port (dataport) with pin settings
you specify: Parameters RS, EN, and WR need to be in range 0–7; Parameters D7 .. D0
need to be a combination of values 0–7 (e.g. 3,6,5,0,7,2,1,4).
Example
Lcd8_Config(&PORTC,&PORTD,0,1,2,6,5,4,3,7,1,2,0);
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Lcd8_Init
Prototype
void Lcd8_Init(char *ctrlport, char *dataport);
Description
Initializes LCD at Control port (ctrlport) and Data port (dataport) with default pin
settings (see the connection scheme at the end of the chapter):
E -> ctrlport.3, RS -> ctrlport.2, R/W -> ctrlport.0, D7 -> dataport.7, D6 -> dataport.6,
D5 -> dataport.5, D4 -> dataport.4, D3 -> dataport.3, D2 -> dataport.2, D1 -> dataport.1,
D0 -> dataport.0
Example
Lcd8_Init(&PORTB, &PORTC);
Lcd8_Out
Prototype
void Lcd8_Out(char row, char col, char *text);
Description
Prints text on LCD at specified row and column (parameter row and col). Both string
variables and literals can be passed as text.
Requires
Ports with LCD must be initialized. See Lcd8_Config or Lcd8_Init.
Example
Lcd8_Out(1, 3, "Hello!");
// Print "Hello!" at line 1, char 3
Lcd8_Out_Cp
Prototype
void Lcd8_Out_Cp(char *text);
Description
Prints text on LCD at current cursor position. Both string variables and literals can be
passed as text.
Requires
Ports with LCD must be initialized. See Lcd8_Config or Lcd8_Init.
Example
Lcd8_Out_Cp("Here!"); // Print "Here!" at current cursor position
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Lcd8_Chr
Prototype
void Lcd8_Chr(char row, char col, char character);
Description
Prints character on LCD at specified row and column (parameters row and col).
Both variables and literals can be passed as character.
Requires
Ports with LCD must be initialized. See Lcd8_Config or Lcd8_Init.
Example
Lcd8_Out(2, 3, 'i');
// Print 'i' at line 2, char 3
Lcd8_Chr_Cp
Prototype
void Lcd8_Chr_Cp(char character);
Description
Prints character on LCD at current cursor position. Both variables and literals can be
passed as character.
Requires
Ports with LCD must be initialized. See Lcd8_Config or Lcd8_Init.
Example
Lcd8_Out_Cp('e');
// Print 'e' at current cursor position
Lcd8_Cmd
Prototype
void Lcd8_Cmd(char command);
Description
Sends command to LCD. You can pass one of the predefined constants to the function.
The complete list of available commands is on the page 186.
Requires
Ports with LCD must be initialized. See Lcd8_Config or Lcd8_Init.
Example
Lcd8_Cmd(Lcd_Clear);
// Clear LCD display
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Library Example (default pin settings)
char *text = "mikroElektronika";
void main() {
TRISB = 0;
TRISC = 0;
Lcd8_Init(&PORTB, &PORTC);
Lcd8_Cmd(Lcd_CURSOR_OFF);
Lcd8_Out(1, 1, text);
}
//
//
//
//
//
PORTB is output
PORTC is output
Initialize LCD at PORTB and PORTC
Turn off cursor
Print text on LCD
Hardware Connection
VCC
MCLR
RB7
RA0
RB6
RA1
RB5
RA2
RB4
RA3
RB3
RA4
RB2
RE0
P3
5K
RE1
Contrast
Adjustment
RE2
VDD
VSS
OSC1
1
GND
VCC
VEE
RS
R/W
E
D0
D1
D2
D3
D4
D5
D6
D7
OSC2
RC0
14
8 MhZ
D0
D1
PICxxxx
RA5
RB1
E
R/W
RS
VCC
RB0
VDD
VSS
RD7
RD6
RD5
RD4
D7
D6
D5
D4
RC7
RC1
RC6
RC2
RC5
RC3
RC4
RD0
RD3
RD1
RD2
D3
D2
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GLCD Library
mikroC provides a library for drawing and writing on Graphic LCD. These routines work with commonly used GLCD 128x64, and work only with the PIC18
family.
Note: Be sure to designate port with GLCD as output, before using any of the following functions.
Library Routines
Basic routines:
Glcd_Init
Glcd_Disable
Glcd_Set_Side
Glcd_Set_Page
Glcd_Set_X
Glcd_Read_Data
Glcd_Write_Data
Advanced routines:
Glcd_Fill
Glcd_Dot
Glcd_Line
Glcd_V_Line
Glcd_H_Line
Glcd_Rectangle
Glcd_Box
Glcd_Circle
Glcd_Set_Font
Glcd_Write_Char
Glcd_Write_Text
Glcd_Image
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Glcd_Init
Prototype
void Glcd_Init(unsigned char *ctrl_port, char cs1, char cs2, char
rs, char rw, char rst, char en, unsigned char *data_port);
Description
Initializes GLCD at lower byte of data_port with pin settings you specify. Parameters
cs1, cs2, rs, rw, rst, and en can be pins of any available port. This function needs to
be called befored using other routines of GLCD library.
Example
Glcd_Init(PORTB, PORTC, 3, 5, 7, 1, 2);
Glcd_Disable
Prototype
void Glcd_Disable(void);
Description
Routine disables the device and frees the data line for other devices. To enable the
device again, call any of the library routines; no special command is required.
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Disable();
Glcd_Set_Side
Prototype
void Glcd_Set_Side(unsigned short x);
Description
Selects side of GLCD, left or right. Parameter x specifies the side: values from 0 to 63
specify the left side, and values higher than 64 specify the right side. Use the functions
Glcd_Set_Side, Glcd_Set_X, and Glcd_Set_Page to specify an exact position on
GLCD. Then, you can use Glcd_Write_Data or Glcd_Read_Data on that location.
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Select_Side(0);
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Glcd_Set_Page
Prototype
void Glcd_Set_Page(unsigned short page);
Description
Selects page of GLCD, technically a line on display; parameter page can be 0..7.
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Set_Page(5);
Glcd_Set_X
Prototype
void Glcd_Set_X(unsigned short x_pos);
Description
Positions to x dots from the left border of GLCD within the given page.
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Set_X(25);
Glcd_Read_Data
Prototype
unsigned short Glcd_Read_Data(void);
Returns
One word from the GLCD memory.
Description
Reads data from from the current location of GLCD memory. Use the functions
Glcd_Set_Side, Glcd_Set_X, and Glcd_Set_Page to specify an exact position on
GLCD. Then, you can use Glcd_Write_Data or Glcd_Read_Data on that location.
Requires
Reads data from from the current location of GLCD memory.
Example
tmp = Glcd_Read_Data();
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Glcd_Write_Data
Prototype
void Glcd_Write_Data(unsigned short data);
Description
Writes data to the current location in GLCD memory and moves to the next location.
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Write_Data(data);
Glcd_Fill
Prototype
void Glcd_Fill(unsigned short pattern);
Description
Fills the GLCD memory with byte pattern. To clear the GLCD screen, use
Glcd_Fill(0); to fill the screen completely, use Glcd_Fill($FF).
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Fill(0);
// Clear screen
Glcd_Dot
Prototype
void Glcd_Dot(unsigned short x, unsigned short y, char color);
Description
Draws a dot on the GLCD at coordinates (x, y). Parameter color determines the dot
state: 0 clears dot, 1 puts a dot, and 2 inverts dot state.
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Dot(0, 0, 2); // Invert the dot in the upper left corner
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Glcd_Line
Prototype
void Glcd_Line(int x1, int y1, int x2, int y2, char color);
Description
Draws a line on the GLCD from (x1, y1) to (x2, y2). Parameter color determines
the dot state: 0 draws an empty line (clear dots), 1 draws a full line (put dots), and 2
draws a “smart” line (invert each dot).
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Line(0, 63, 50, 0, 2);
Glcd_V_Line
Prototype
void Glcd_V_Line(unsigned short y1, unsigned short y2, unsigned
short x, char color);
Description
Similar to GLcd_Line, draws a vertical line on the GLCD from (x, y1) to
(x, y2).
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_V_Line(0, 63, 0, 1);
Glcd_H_Line
Prototype
void Glcd_H_Line(unsigned short x1, unsigned short x2, unsigned
short y, char color);
Description
Similar to GLcd_Line, draws a horizontal line on the GLCD from (x1, y) to
(x2, y).
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_H_Line(0, 127, 0, 1);
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Glcd_Rectangle
Prototype
void Glcd_Rectangle(unsigned short x1, unsigned short y1,
unsigned short x2, unsigned short y2, char color);
Description
Draws a rectangle on the GLCD. Parameters (x1, y1) set the upper left corner,
(x2, y2) set the bottom right corner. Parameter color defines the border: 0 draws an
empty border (clear dots), 1 draws a solid border (put dots), and 2 draws a “smart” border (invert each dot).
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Rectangle(10, 0, 30, 35, 1);
Glcd_Box
Prototype
void Glcd_Box(unsigned short x1, unsigned short y1, unsigned
short x2, unsigned short y2, char color);
Description
Draws a box on the GLCD. Parameters (x1, y1) set the upper left corner, (x2, y2)
set the bottom right corner. Parameter color defines the fill: 0 draws a white box (clear
dots), 1 draws a full box (put dots), and 2 draws an inverted box (invert each dot).
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Box(10, 0, 30, 35, 1);
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Glcd_Circle
Prototype
void Glcd_Circle(int x, int y, int radius, char color);
Description
Draws a circle on the GLCD, centered at (x, y) with radius. Parameter color defines the
circle line: 0 draws an empty line (clear dots), 1 draws a solid line (put dots), and 2
draws a “smart” line (invert each dot).
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Circle(63, 31, 25, 2);
Glcd_Set_Font
Prototype
void Glcd_Set_Font(const char *font, unsigned short font_width,
unsigned short font_height, unsigned font_offset);
Description
Sets font for routines Glcd_Write_Char and Glcd_Write_Text. Parameter font
needs to formatted in an array of byte.
Parameters font_width and font_height specify the width and height of characters
in dots. Font width should not exceed 128 dots, and font height shouldn’t exceed 8 dots.
Parameter font_offset determines the ASCII character from which the supplied font
starts. Demo fonts supplied with the library have an offset of 32, which means that they
start with space.
You can create your own fonts by following the guidelines given in file
“GLcd_Fonts.c”. This file contains the default fonts for GLCD, and is located in your
installation folder, “Extra Examples” > “GLCD”.
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
// Use the custom 5x8 font "myfont" which starts with space (32):
Glcd_Set_Font(myfont_5x8, 5, 8, 32);
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Glcd_Write_Char
Prototype
void Glcd_Write_Char(unsigned short character, unsigned short x,
unsigned short page, char color);
Description
Prints character at page (one of 8 GLCD lines, 0..7), x dots away from the left border of display. Parameter color defines the “fill”: 0 prints a “white” letter (clear dots),
1 prints a solid letter (put dots), and 2 prints a “smart” letter (invert each dot).
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Write_Char('C', 0, 0, 1);
Glcd_Write_Text
Prototype
void Glcd_Write_Text(char *text, unsigned short x, unsigned short
page, unsigned short color);
Description
Prints text at page (one of 8 GLCD lines, 0..7), x dots away from the left border of
display. Parameter color defines the “fill”: 0 prints a “white” letters (clear dots), 1
prints solid letters (put dots), and 2 prints “smart” letters (invert each dot).
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Write_Text("Hello world!", 0, 0, 1);
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Glcd_Image
Prototype
void Glcd_Image(const char *image);
Description
Displays bitmap image on the GLCD. Parameter image should be formatted as an array
of integers. Use the mikroC’s integrated Bitmap-to-LCD editor (menu option Tools >
BMP2LCD) to convert image to a constant array suitable for display on GLCD.
Requires
GLCD needs to be initialized. See Glcd_Init.
Example
Glcd_Image(my_image);
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Library Example
The following drawing demo tests advanced routines of GLCD library.
unsigned short j, k;
void main() {
Glcd_Init(PORTB, 2, 0, 3, 5, 7, 1, PORTD);
// Set font for displaying text
Glcd_Set_Font(@FontSystem5x8, 5, 8, 32);
do {
// Draw circles
Glcd_Fill(0); // Clear screen
Glcd_Write_Text("Circles", 0, 0, 1);
j = 4;
while (j < 31) {
Glcd_Circle(63, 31, j, 2);
j += 4;
}
Delay_ms(4000);
// Draw boxes
Glcd_Fill(0); // Clear screen
Glcd_Write_Text("Rectangles", 0, 0, 1);
j = 0;
while (j < 31) {
Glcd_Box(j, 0, j + 20, j + 25, 2);
j += 4;
}
Delay_ms(4000);
// Draw Lines
Glcd_Fill(0); // Clear screen
Glcd_Write_Text("Lines", 0, 0, 1);
for (j = 0; j < 16; j++) {
k = j*4 + 3;
Glcd_Line(0, 0, 127, k, 2);
}
for (j = 0; j < 31; j++) {
k = j*4 + 3;
Glcd_Line(0, 63, k, 0, 2);
}
Delay_ms(4000);
} while (1);
}//~!
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P3
5K
Vo
MikroElektronika: Development tools - Books - Compilers
VCC
20
VCC
mikroElektronika
Compilers
Tools
Books
1
Contrast
Adjustment
CS1
CS2
GND
VCC
Vo
RS
R/W
E
D0
D1
D2
D3
D4
D5
D6
D7
RST
Vee
LED+
LED-
Vee
8 MhZ
D0
D1
RC7
RD4
RD5
RD6
RD7
VSS
VDD
RB0
RB1
RB2
RB3
RB4
RB5
RB6
RB7
RD0
RD2
RD3
RC3
RD1
RC5
RC4
RC2
RC6
PICxxxx
RC1
RC0
OSC2
OSC1
VSS
VDD
RE2
RE1
RE0
RA5
RA4
RA3
RA2
RA1
RA0
MCLR
D2
D3
D4
D5
D6
D7
CS1
CS2
RS
R/W
E
RST
VCC
making it simple...
mikroC
mikroC - C Compiler for Microchip PIC microcontrollers
Hardware Connection
page
261
mikroC
mikroC - C Compiler for Microchip PIC microcontrollers
making it simple...
T6963C Graphic LCD Library
mikroC provides a library for drawing and writing on Toshiba T6963C Graphic
LCD (changeable size).
Note: Be sure to designate port with GLCD as output, before using any of the following library functions.
Library Routines
T6963C_init
T6963C_writeData
T6963C_writeCommand
T6963C_setPtr
T6963C_waitReady
T6963C_fill
T6963C_dot
T6963C_write_char
T6963C_write_text
T6963C_line
T6963C_rectangle
T6963C_box
T6963C_circle
T6963C_image
T6963C_sprite
T6963C_set_cursor
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T6963C_init
Prototype
void T6963C_init(unsigned int w, unsigned int h, unsigned int
fntW, unsigned int *data, unsigned int *cntrl, unsigned int
bitwr, unsigned int bitrd, unsigned int bitcd, unsigned int
bitreset);
Description
Initalizes the Graphic Lcd controller. This function must be called before all T6963C
Library Routines.
width - Number of horizontal (x) pixels in the display.
height - Number of vertical (y) pixels in the display.
fntW - Font width, number of pixels in a text character, must be set accordingly to the
hardware.
data - Address of the port on which the Data Bus is connected.
cntrl - Address of the port on which the Control Bus is connected.
wr - !WR line bit number in the *cntrl port.
rd - !RD line bit number in the *cntrl port.
cd - !CD line bit number in the *cntrl port.
rst - !RST line bit number in the *cntrl port.
Display RAM :
The library doesn't know the amount of available RAM.
The library cuts the RAM into panels : a complete panel is one graphics panel followed
by a text panel, The programer has to know his hardware to know how much panel he
has.
Requires
Nothing.
Example
T6963C_init(240, 128, 8, &PORTF, &PORTD, 5, 7, 6, 4) ;
/*
* init display for 240 pixel width and 128 pixel height
* 8 bits character width
* data bus on PORTF
* control bus on PORTD
* bit 5 is !WR
* bit 7 is !RD
* bit 6 is C!D
* bit 4 is RST
*/
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T6963C_writeData
Prototype
void T6963C_writeData(unsigned char data);
Description
Routine that writes data to T6963C controller.
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_writeData(AddrL);
T6963C_writeCommand
Prototype
void T6963C_writeCommand(unsigned char data);
Description
Routine that writes command to T6963C controller.
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_writeCommand(T6963C_CURSOR_POINTER_SET);
T6963C_setPtr
Prototype
void T6963C_setPtr(unsigned int addr, unsigned char t);
Description
This routine sets the memory pointer p for command c.
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_writeCommand(T6963C_CURSOR_POINTER_SET);
T6963C_waitReady
Prototype
void T6963C_waitReady(void);
Description
This routine pools the status byte, and loops until ready.
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_waitReady();
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T6963C_fill
Prototype
void T6963C_fill(unsigned char data, unsigned int start, unsigned
int len);
Description
This routine fills length with bytes to controller memory from start address.
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_fill(0x33,0x00FF,0x000F);
T6963C_dot
Prototype
void T6963C_dot(int x, int y, unsigned char color);
Description
This sets current text work panel. It writes string str row x line y. mode =
T6963C_ROM_MODE_[OR|EXOR|AND].
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_dot(x0, y0, pcolor);
T6963C_write_char
Prototype
void T6963C_dot(int x, int y, unsigned char color);
Description
This routine sets current text work panel.
It writes char c row x line y.
mode = T6963C_ROM_MODE_[OR|EXOR|AND]
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_write_char('A',22,23,AND);
T6963C_write_text
Prototype
void T6963C_write_text(unsigned char *str, unsigned char x,
unsigned char y, unsigned char mode);
Description
This sets current text work panel.
It writes string str row x line y.
mode = T6963C_ROM_MODE_[OR|EXOR|AND]
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_write_text(" GLCD LIBRARY DEMO, WELCOME !", 0, 0,
T6963C_ROM_MODE_XOR);
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T6963C_line
Prototype
void T6963C_line(int px0, int py0, int px1, int py1, unsigned
char pcolor);
Description
This routine current graphic work panel.
It's draw a line from (x0, y0) to (x1, y1).
pcolor = T6963C_[WHITE[BLACK]
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_line(0, 0, 239, 127, T6963C_WHITE);
T6963C_rectangle
Prototype
void T6963C_rectangle(int x0, int y0, int x1, int y1, unsigned
char pcolor);
Description
It sets current graphic work panel.
It draws the border of the rectangle (x0, y0)-(x1, y1).
pcolor = T6963C_[WHITE[BLACK].
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_rectangle(20, 20, 219, 107, T6963C_WHITE);
T6963C_box
Prototype
void T6963C_box(int x0, int y0, int x1, int y1, unsigned char
pcolor);
Description
This routine sets current graphic work panel.
It draws a solid box in the rectangle (x0, y0)-(x1, y1).
pcolor = T6963C_[WHITE[BLACK].
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_box(0, 119, 239, 127, T6963C_WHITE);
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T6963C_circle
Prototype
void T6963C_circle(int x, int y, long r, unsigned char pcolor);
Description
This routine sets current graphic work panel.
It draws a circle, center is (x, y), diameter is r.
pcolor = T6963C_[WHITE[BLACK]
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_circle(120, 64, 110, T6963C_WHITE);
T6963C_image
Prototype
void T6963C_image(const char *pic);
Description
This routine sets current graphic work panel :
It fills graphic area with picture pointer by MCU.
MCU must fit the display geometry.
For example : for a 240x128 display, MCU must be an array of (240/8)*128 = 3840
bytes .
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_image(mc);
T6963C_sprite
Prototype
void T6963C_sprite(unsigned char px, unsigned char py, const char
*pic, unsigned char sx, unsigned char sy);
Description
This routine sets current graphic work panel.
It fills graphic rectangle area (px, py)-(px + sx, py + sy) witch picture pointed by MCU.
Sx and sy must be the size of the picture.
MCU must be an array of sx*sy bytes.
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_sprite(76, 4, einstein, 88, 119); // draw a sprite
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T6963C_set_cursor
Prototype
void T6963C_set_cursor(unsigned char x, unsigned char y);
Description
This routine sets cursor row x line y.
Requires
Ports must be initialized. See T6963C_init.
Example
T6963C_set_cursor(cposx, cposy);
Library Example
The following drawing demo tests advanced routines of T6963C GLCD library.
#include
"T6963C.h"
/*
* bitmap pictures stored in ROM
*/
extern const char mc[] ;
extern const char einstein[] ;
/*
* initial PWM duty cycle for contrast power supply
*/
unsigned char
PWM_duty = 200 ;
void main(void)
{
unsigned
unsigned
unsigned
unsigned
char
int
char
int
panel ;
// current panel
i ;
// general purpose register
curs ;
// cursor visibility
cposx, cposy ; // cursor x-y position
TRISC = 0 ;
PORTC = 0b00000000 ;
// port C is output only
// chip enable, reverse on, 8x8 font
//continues...
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//continued...
/*
* init display for 240 pixel width and 128 pixel height
* 8 bits character width
* data bus on PORTD
* control bus on PORTC
* bit 3 is !WR
* bit 1 is !RD
* bit 1 is C!D
* bit 5 is RST
*/
T6963C_init(240, 128, 8, &PORTD, &PORTC, 3, 2, 1, 5) ;
/*
* enable both graphics and text display at the same time
*/
T6963C_graphics(1) ;
T6963C_text(1) ;
panel = 0 ;
i = 0 ;
curs = 0 ;
cposx = cposy = 0 ;
/*
* text messages
*/
T6963C_write_text(" GLCD LIBRARY DEMO, WELCOME !", 0, 0,
T6963C_ROM_MODE_XOR) ;
T6963C_write_text(" EINSTEIN WOULD HAVE LIKED mC", 0, 15,
T6963C_ROM_MODE_XOR) ;
/*
* cursor
*/
T6963C_cursor_height(8) ;
T6963C_set_cursor(0, 0) ;
T6963C_cursor(0) ;
// 8 pixel height
// move cursor to top left
// cursor off
/*
* draw rectangles
*/
T6963C_rectangle(0, 0, 239, 127, T6963C_WHITE) ;
T6963C_rectangle(20, 20, 219, 107, T6963C_WHITE) ;
T6963C_rectangle(40, 40, 199, 87, T6963C_WHITE) ;
T6963C_rectangle(60, 60, 179, 67, T6963C_WHITE) ;
//continues...
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mikroC - C Compiler for Microchip PIC microcontrollers
//continued...
/*
* draw a cross
*/
T6963C_line(0, 0, 239, 127, T6963C_WHITE) ;
T6963C_line(0, 127, 239, 0, T6963C_WHITE) ;
/*
* draw solid boxes
*/
T6963C_box(0, 0, 239, 8, T6963C_WHITE) ;
T6963C_box(0, 119, 239, 127, T6963C_WHITE) ;
/*
* draw circles
*/
T6963C_circle(120,
T6963C_circle(120,
T6963C_circle(120,
T6963C_circle(120,
T6963C_circle(120,
T6963C_circle(120,
T6963C_circle(120,
64,
64,
64,
64,
64,
64,
64,
10, T6963C_WHITE) ;
30, T6963C_WHITE) ;
50, T6963C_WHITE) ;
70, T6963C_WHITE) ;
90, T6963C_WHITE) ;
110, T6963C_WHITE) ;
130, T6963C_WHITE) ;
T6963C_sprite(76, 4, einstein, 88, 119) ;
// draw a sprite
T6963C_setGrPanel(1) ;
// select other graphic panel
T6963C_image(mc) ;
// fill the graphic screen with a picture
for(;;)
{
/*
* if RB1 is pressed, toggle the display between
graphic panel 0 and graphic 1
*/
if(PORTB & 0b00000010)
{
panel++ ;
panel &= 1 ;
T6963C_displayGrPanel(panel) ;
Delay_ms(300) ;
}
}
//continues...
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mikroC
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mikroC - C Compiler for Microchip PIC microcontrollers
//continued...
/*
* if RB2 is pressed, display only graphic panel
*/
else if(PORTB & 0b00000100)
{
T6963C_graphics(1) ;
T6963C_text(0) ;
Delay_ms(300) ;
}
/*
* if RB3 is pressed, display only text panel
*/
else if(PORTB & 0b00001000)
{
T6963C_graphics(0) ;
T6963C_text(1) ;
Delay_ms(300) ;
}
/*
* if RB4 is pressed, display text and graphic
panels
*/
else if(PORTB & 0b00010000)
{
T6963C_graphics(1) ;
T6963C_text(1) ;
Delay_ms(300) ;
}
/*
* if RB5 is pressed, change cursor
*/
else if(PORTB & 0b00100000)
{
curs++ ;
if(curs == 3) curs = 0 ;
switch(curs)
//continues...
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//continued...
/*
* move cursor, even if not visible
*/
cposx++ ;
if(cposx == T6963C_txtCols)
{
cposx = 0 ;
cposy++ ;
if(cposy == T6963C_grHeight / T6963C_CHARACTER_HEIGHT)
{
cposy = 0 ;
}
}
T6963C_set_cursor(cposx, cposy) ;
Delay_ms(100) ;
}
}
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mikroC
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mikroC - C Compiler for Microchip PIC microcontrollers
Hardware Connection
11
12
13
14
RS 16
8 Mhz
R/W 17
E 18
D0 19
D1 20
VCC
GND
OSC1
OSC2
RC1
RC2
PIC18F452
VCC
RD7
RD6
RD5
RD4
RC5
RC3
RD0
RD3
RD1
RD2
30
D7
29
D6
28
D5
27
D4
24
RST
22
D3
21
D2
Contrast
Adjustment
P1
10K
VCC
VCC
R1
50
20
VSS
VDD
Vo
RS
R/W
E
D0
D1
D2
D3
D4
D5
D6
D7
CE
RST
VEE
MD
FS
LED+
1
mikroE
EasyPIC3
Dev. tool
Toshiba T6963C Graphic LCD (240x128)
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mikroC
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mikroC - C Compiler for Microchip PIC microcontrollers
Manchester Code Library
mikroC provides a library for handling Manchester coded signals. Manchester
code is a code in which data and clock signals are combined to form a single selfsynchronizing data stream; each encoded bit contains a transition at the midpoint
of a bit period, the direction of transition determines whether the bit is a 0 or a 1;
second half is the true bit value and the first half is the complement of the true bit
value (as shown in the figure below).
Manchester RF_Send_Byte format
St1 St2 Ctr B7 B6 B5 B4 B3 B2 B1 B0
Bi-phase coding
1
2.4ms
0
Example of transmission
1 1 0 0 01 0 0 01 1
Notes: Manchester receive routines are blocking calls (Man_Receive_Config,
Man_Receive_Init, Man_Receive). This means that PIC will wait until the
task is performed (e.g. byte is received, synchronization achieved, etc). Routines
for receiving are limited to a baud rate scope from 340 ~ 560 bps.
Library Routines
Man_Receive_Config
Man_Receive_Init
Man_Receive
Man_Send_Config
Man_Send_Init
Man_Send
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Man_Receive_Config
Prototype
void Man_Receive_Config(char *port, char rxpin);
Description
The function prepares PIC for receiving signal. You need to specify the port and
rxpin (0–7) of input signal. In case of multiple errors on reception, you should call
Man_Receive_Init once again to enable synchronization.
Example
Man_Receive_Config(&PORTD, 6);
Man_Receive_Init
Prototype
void Man_Receive_Init(char *port);
Description
The function prepares PIC for receiving signal. You need to specify the port; rxpin is
pin 6 by default. In case of multiple errors on reception, you should call
Man_Receive_Init once again to enable synchronization.
Example
Man_Receive_Init(&PORTD);
Man_Receive
Prototype
void Man_Receive(char *error);
Returns
Returns one byte from signal.
Description
Function extracts one byte from signal. If signal format does not match the expected,
error flag will be set to 255.
Requires
To use this function, you must first prepare the PIC for receiving. See
Man_Receive_Config or Man_Receive_Init.
Example
temp = Man_Receive(error);
if (error) { ... /* error handling */ }
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Man_Send_Config
Prototype
void Man_Send_Config(char *port, char txpin);
Description
The function prepares PIC for sending signal. You need to specify port and txpin
(0–7) for outgoing signal. Baud rate is const 500 bps.
Example
Man_Send_Config(&PORTD, 0);
Man_Send_Init
Prototype
void Man_Receive_Init(char *port);
Description
The function prepares PIC for sending signal. You need to specify port for outgoing
signal; txpin is pin 0 by default. Baud rate is const 500 bps.
Example
Man_Send_Init(&PORTD);
Man_Send
Prototype
void Man_Send(unsigned short data);
Description
Sends one byte (data).
Requires
To use this function, you must first prepare the PIC for sending. See
Man_Send_Config or Man_Send_Init.
Example
unsigned short msg;
...
Man_Send(msg);
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Library Example
unsigned short error, ErrorCount, IdleCount, temp, LetterCount;
void main() {
ErrorCount = 0;
TRISC
= 0;
PORTC
= 0;
Man_Receive_Config(&PORTD, 6);
Lcd_Init(&PORTB);
while (1) {
IdleCount = 0;
do {
temp = Man_Receive(error);
if (error)
ErrorCount++
else
PORTC = 0;
if (ErrorCount > 20) {
ErrorCount = 0;
PORTC = 0xAA;
Man_Receive_Init(&PORTD);
}
IdleCount++;
if (IdleCount > 18) {
IdleCount = 0;
Man_Receive_Init(&PORTD);
}
} while (temp != 0x0B);
if (error != 255) {
Lcd_Cmd(LCD_CLEAR);
LetterCount = 0;
while (LetterCount < 17) {
LetterCount++;
temp = Man_Receive(error);
if (error != 255)
Lcd_Chr_Cp(temp)
else {
ErrorCount++; break;
}
}
temp = Man_Receive(error);
if (temp != 0x0E)
ErrorCount++;
} // end if
} // end while
}//~!
// Error indicator
// Synchronize receiver
// Initialize LCD on PORTB
// Endless loop
// Reset idle counter
// Attempt byte receive
// If there are too many errors
//
syncronize the receiver again
// Indicate error
// Synchronize receiver
// If nothing received after some time
//
try to synchronize again
// Synchronize receiver
// End of message marker
// If no error then write the message
// Message is 16 chars long
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mikroC - C Compiler for Microchip PIC microcontrollers
Hardware Connection
Transmitter RF
module
Antenna
11
VCC
12
13
14
VCC
GND
OSC1
OSC2
8 Mhz
PIC18F452
VCC
VCC
A
RT4
In
19
RD0
GND
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Receiver RF
module
Antenna
11
12
RR4
13
14
VCC
GND
OSC1
OSC2
Receiver RF
module
8 Mhz
20
PIC18F452
VCC
RD1
VCC
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Multi Media Card Library
mikroC provides a library for accessing data on Multi Media Card via SPI
communication. This library supports Secure Digital (SD) flash memory card standard also.
Notes:
- Library works with PIC18 family only;
- Library functions create and read files from the root directory only;
- Library functions populate both FAT1 and FAT2 tables when writing to files, but
the file data is being read from the FAT1 table only; i.e. there is no recovery if
FAT1 table is corrupted.
- Since version 5.0.0.3, library can cope with media that have the Master Boot
Record (MBR) in sector 0. It reads the necessary information from it, and jumps
to the first available primary logical partition. For more information on MBR,
physical and logiacl drives, primary/secondary partitions and partition tables,
please consult other resources, e.g. Wikipedia and similar.
Note: Spi_Init_Advanced(MASTER_OSC_DIV16, DATA_SAMPLE_MIDDLE,
CLK_IDLE_LOW, LOW_2_HIGH); must be called before initializing Mmc_Init.
Library Routines
Mmc_Init
Mmc_Read_Sector
Mmc_Write_Sector
Mmc_Read_Cid
Mmc_Read_Csd
Mmc_Fat_Init
Mmc_Fat_Assign
Mmc_Fat_Reset
Mmc_Fat_Rewrite
Mmc_Fat_Append
Mmc_Fat_Read
Mmc_Fat_Write
Mmc_Set_File_Date
Mmc_Fat_Delete
Mmc_Fat_Get_File_Date
Mmc_Fat_Get_File_Size
Mmc_Fat_Get_Swap_File
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Mmc_Init
Prototype
unsigned short Mmc_Init(char *port, char pin);
Returns
Returns 1 if MMC card is present and successfully initialized, otherwise returns 0.
Description
Initializes MMC through hardware SPI communication, with chip select pin being
given by the parameters port and pin; communication port and pins are designated by
the hardware SPI settings for the respective MCU. Function returns 1 if MMC card is
present and successfully initialized, otherwise returns 0.
Requires
Spi_Init_Advanced(MASTER_OSC_DIV16, DATA_SAMPLE_MIDDLE,
CLK_IDLE_LOW, LOW_2_HIGH); must be called before calling Mmc_Init.
Example
while (!Mmc_Init(&PORTC,2)) ;
// Loop until MMC is initialized
Mmc_Read_Sector
Prototype
unsigned short Mmc_Read_Sector(unsigned long sector, char *data);
Returns
Returns 0 if read was successful, or 1 if an error occurred.
Description
Function reads one sector (512 bytes) from MMC card at sector address sector. Read
data is stored in the array data. Function returns 0 if read was successful, or 1 if an
error occurred.
Requires
Library needs to be initialized, see Mmc_Init.
Example
error = Mmc_Read_Sector(sector, data);
Mmc_Write_Sector
Prototype
unsigned short Mmc_Write_Sector(unsigned long sector,char *data);
Returns
Returns 0 if write was successful; returns 1 if there was an error in sending write command; returns 2 if there was an error in writing.
Description
Function writes 512 bytes of data to MMC card at sector address sector. Function
returns 0 if write was successful, or 1 if there was an error in sending write command,
or 2 if there was an error in writing.
Requires
Library needs to be initialized, see Mmc_Init.
Example
error = Mmc_Write_Sector(sector, data);
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Mmc_Read_Cid
Prototype
unsigned short Mmc_Read_Cid(unsigned short *data_for_registers);
Returns
Returns 0 if read was successful, or 1 if an error occurred.
Description
Function reads CID register and returns 16 bytes of content into
data_for_registers.
Requires
Library needs to be initialized, see Mmc_Init.
Example
error = Mmc_Read_Cid(data);
Mmc_Read_Csd
Prototype
unsigned short Mmc_Read_Csd(unsigned short *data_for_registers);
Returns
Returns 0 if read was successful, or 1 if an error occurred.
Description
Function reads CSD register and returns 16 bytes of content into
data_for_registers.
Requires
Library needs to be initialized, see Mmc_Init.
Example
error = Mmc_Read_Csd(data);
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Mmc_Fat_Init
Prototype
unsigned short Mmc_Fat_Init(unsigned short *port, unsigned short
pin);
Returns
Returns 0 if MMC card is present and successfully initialized, otherwise returns 1.
Description
Initializes hardware SPI communication; designated CS line for communication is RC2.
The function returns 0 if MMC card is present and successfully initialized, otherwise
returns 1.
This function needs to be called before using other functions of MMC FAT library.
Requires
Spi_Init_Advanced(MASTER_OSC_DIV16, DATA_SAMPLE_MIDDLE,
CLK_IDLE_LOW, LOW_2_HIGH); must be called before calling Mmc_Fat_Init.
Example
// Loop until MMC FAT is initialized at RC2
while (Mmc_Fat_Init(&PORTC, 2)) ;
Mmc_Fat_Assign
Prototype
void Mmc_Fat_Assign(char *filename);
Description
This routine designates (“assigns”) the file we’ll be working with. Function looks for the
file specified by the filename in the root directory. If the file is found, routine will initialize it by getting its start sector, size, etc. If the file is not found, an empty file will be
created with the given name. The filename must be 8 + 3 characters in uppercase.
Requires
Library needs to be initialized; see Mmc_Fat_Init.
Example
// Assign the file "EXAMPLE1.TXT" in the root directory of MMC.
// If the file is not found, routine will create one.
Mmc_Fat_Assign("EXAMPLE1TXT");
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Mmc_Fat_Reset
Prototype
void Mmc_Fat_Reset(unsigned long *size);
Description
Function resets the file pointer (moves it to the start of the file) of the assigned file, so
that the file can be read. Parameter size stores the size of the assigned file, in bytes.
Requires
Library needs to be initialized; see Mmc_Fat_Init.
Example
Mmc_Fat_Reset(&filesize);
Mmc_Fat_Rewrite
Prototype
void Mmc_Fat_Rewrite(void);
Description
Function resets the file pointer and clears the assigned file, so that new data can be written into the file.
Requires
Library needs to be initialized; see Mmc_Fat_Init.
Example
Mmc_Fat_Rewrite();
Mmc_Fat_Append
Prototype
void Mmc_Fat_Append(void);
Description
The function moves the file pointer to the end of the assigned file, so that data can be
appended to the file.
Requires
Library needs to be initialized; see Mmc_Fat_Init.
Example
Mmc_Fat_Append();
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Mmc_Fat_Read
Prototype
void Mmc_Fat_Read(unsigned short *data);
Description
Function reads the byte at which the file pointer points to and stores data into parameter
data. The file pointer automatically increments with each call of Mmc_Fat_Read.
Requires
File pointer must be initialized; see Mmc_Fat_Reset.
Example
Mmc_Fat_Read(&mydata);
Mmc_Fat_Write
Prototype
void Mmc_Fat_Write(char *fdata, unsigned data_len);
Description
Function writes a chunk of data_len bytes (fdata) to the currently assigned file, at
the position of the file pointer.
Requires
File pointer must be initialized; see Mmc_Fat_Append or Mmc_Fat_Rewrite.
Example
Mmc_Fat_Write(txt, 21);
Mmc_Fat_Write("Hello\nworld", 1);
Mmc_Set_File_Date
Prototype
void Mmc_Set_File_Date(unsigned year, char month, char day,
char hours, char min, char sec);
Description
Writes system timestamp to a file. Use this routine before each writing to the file; otherwise, file will be appended a random timestamp.
Requires
File pointer must be initialized; see Mmc_Fat_Append or Mmc_Fat_Rewrite.
Example
// April 1st 2005, 18:07:00
Mmc_Set_File_Date(2005, 4, 1, 18, 7, 0);
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Mmc_Fat_Delete
Prototype
void Mmc_Fat_Delete();
Description
Deletes file from MMC.
Requires
Ports must be initialized for FAT operations with MMC.
See Mmc_Fat_Init. File must be assigned. See Mmc_Fat_Assign.
Example
Mmc_Fat_Delete;
Mmc_Fat_Get_File_Date
Prototype
void Mmc_fat_Get_File_Date(unsigned int *year, unsigned short
*month, unsigned short *day, unsigned short *hours, unsigned
short *mins);
Description
Reads time attributes of file.You can read file year, month, day. hours, mins, seconds.
Requires
Ports must be initialized for FAT operations with MMC.
See Mmc_Fat_Init.
File must be assigned.
See Mmc_Fat_Assign.
Example
Mmc_Fat_Get_File_Date(year, month, day, hours, mins);
Mmc_Fat_Get_File_Size
Prototype
unsigned long Mmc_fat_Get_File_Size();
Description
This function returns size of file in bytes.
Requires
Ports must be initialized for FAT operations with MMC.
See Mmc_Fat_Init.
File must be assigned. See Mmc_Fat_Assign.
Example
Mmc_Fat_Get_File_Size;
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Mmc_Fat_Get_Swap_File
Prototype
unsigned long Mmc_Fat_Get_Swap_File(unsigned long sectors_cnt);
Returns
No. of start sector for the newly created swap file, if swap file was created; otherwise,
the function returns zero.
Description
This function is used to create a swap file on the MMC/SD media. It accepts as sectors_cnt argument the number of consecutive sectors that user wants the swap file to
have. During its execution, the function searches for the available consecutive sectors,
their number being specified by the sectors_cnt argument. If there is such space on the
media, the swap file named MIKROSWP.SYS is created, and that space is designated
(in FAT tables) to it. The attributes of this file are: system, archive and hidden, in order
to distinct it from other files. If a file named MIKROSWP.SYS already exists on the
media, this function deletes it upon creating the new one.
The purpose of the swap file is to make reading and writing to MMC/SD media as fast
as possible, by using the Mmc_Read_Sector() and Mmc_Write_Sector() functions
directly, without potentially damaging the FAT system. Swap file can be considered as a
"window" on the media where user can freely write/read the data, in any way (s)he
wants to. Its main purpose in mikroC's library is to be used for fast data acquisition;
when the time-critical acquisition has finished, the data can be re-written into a "normal" file, and formatted in the most suitable way.
Requires
Ports must be initialized for FAT operations with MMC.
See Mmc_Fat_Init.
Example
//Tries to create a swap file, whose size will be at least 1000
//sectors.
//If it succeeds, it sends the No. of start sector over USART
void M_Create_Swap_File() {
size = Mmc_Fat_Get_Swap_File(1000);
if (size) {
Usart_Write(0xAA);
Usart_Write(Lo(size));
Usart_Write(Hi(size));
Usart_Write(Higher(size));
Usart_Write(Highest(size));
Usart_Write(0xAA);
}
}//~
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Library Example
The following code tests MMC library routines. First, we fill the buffer with 512 “M” characters
and write it to sector 56; then we repeat the sequence with character “E” at sector 56. Finally, we
read the sectors 55 and 56 to check if the write was successful.
unsigned i;
unsigned short tmp;
unsigned short data[512];
void main() {
Usart_Init(9600);
Spi_Init_Advanced(MASTER_OSC_DIV16, DATA_SAMPLE_MIDDLE, CLK_IDLE_LOW,LOW_2_HIGH);
// Initialize SPI
// Wait until MMC is initialized
while (!Mmc_Init(&PORTC, 2)) ;
// Fill the buffer with the 'M' character
for (i = 0; i <= 511; i++) data[i] = "M";
// Write it to MMC card, sector 55
tmp = Mmc_Write_Sector(55, data);
// Fill the buffer with the 'E' character
for (i = 0; i <= 511; i++) data[i] = "E";
// Write it to MMC card, sector 56
tmp = Mmc_Write_Sector(56, data);
// Read from sector 55
tmp = Mmc_Read_Sector(55, data);
// Send 512 bytes from buffer to USART
if (tmp == 0)
for (i = 0; i < 512; i++) Usart_Write(data[i]);
// Read from sector 56
tmp = Mmc_Read_Sector(56, data);
// Send 512 bytes from buffer to USART
if (tmp == 0)
for (i = 0; i < 512; i++) Usart_Write(data[i]);
}//~!
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Library Example
The following program tests MMC FAT routines. It creates 5 different files in the root of MMC
card, and fills them with some data. You can check the file dates which should be different.
char FAT_ERROR[20] = "FAT16 not found";
char file_contents[50] = "XX MMC/SD FAT16 library by Anton Rieckert";
char filename[14] = "MIKRO00xTXT"; // File names
unsigned short tmp, character, loop;
long i, size;
void main() {
PORTB = 0;
TRISB = 0;
Usart_Init(19200); // Set up USART for reading the files
Spi_Init_Advanced(MASTER_OSC_DIV16, DATA_SAMPLE_MIDDLE, CLK_IDLE_LOW,LOW_2_HIGH);
// Initialize SPI
if (!Mmc_Fat_Init(&PORTC, 2)) { // Try to find the FAT
tmp = 0;
while (FAT_ERROR[tmp])
Usart_Write(FAT_ERROR[tmp++]);
}
for (loop = 1; loop <= 5; loop++) { // We want 5 files on our MMC card
filename[7] = loop + 64;
// Set number 1, 2, 3, 4 or 5
Mmc_Fat_Assign(&filename,1);
// If file not found, create new file
Mmc_Fat_Rewrite();
// Clear the file, start with new data
file_contents[0] = loop / 10 + 48;
file_contents[1] = loop % 10 + 48;
Mmc_Fat_Write(file_contents, 41); // Write data to the assigned file
Mmc_Fat_Append();
// Add more data to file
Mmc_Fat_Write(file_contents, 41); // Write data to file
Delay_ms(200);
}
// Now if we want to add more data to those same files
for (loop = 1; loop <= 5; loop++) {
filename[7] = loop + 64;
Mmc_Fat_Assign(&filename, 1);
// Assign a file
Mmc_Fat_Append();
Mmc_Fat_Set_File_Date(2005,6,21,10,loop,0);
Mmc_Fat_Write(" for mikroElektronika 2005\r\n", 30);
Mmc_Fat_Append();
Mmc_Fat_Write(file_contents, 41);
Mmc_Fat_Reset(&size);
// To read file, returns file size
for (i = 1; i <= size; i++) {
// Write whole file to USART
Mmc_Fat_Read(&character);
Usart_Write(character);
}
Delay_ms(200);
}
}//~!
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Hardware Connection
REG2
VCC
VCC3
11
12
13
8 Mhz
14
VCC
GND
OSC1
OSC2
C20
100nF
PIC18F452
VCC
C19
100nF 1
3
GND
2
VIN
VOUT
VCC3
E15
10uF
SPI-MISO
MMC-CS#
SPI-MOSI
SPI-SCK
R13
2K2
17
18
MC33269 VCC
DT-3.3
R15
2K2
R17
2K2
1
2
3
4
5
6
7
24
RC2
RC5
RC3
RC4
VCC3
23
R14
3K3
R16
3K3
R18
3K3
CS
Din
GND
+3.3V
SCK
GND
Dout
MMC/SD
CARD
1 2 3 4 5 6 7
MMC
Back view
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OneWire Library
OneWire library provides routines for communication via OneWire bus, for example with DS1820 digital thermometer. This is a Master/Slave protocol, and all the
cabling required is a single wire. Because of the hardware configuration it uses
(single pullup and open collector drivers), it allows for the slaves even to get their
power supply from that line.
Some basic characteristics of this protocol are:
- single master system,
- low cost,
- low transfer rates (up to 16 kbps),
- fairly long distances (up to 300 meters),
- small data transfer packages.
Each OneWire device also has a unique 64-bit registration number (8-bit device
type, 48-bit serial number and 8-bit CRC), so multiple slaves can co-exist on the
same bus.
Note that oscillator frequency Fosc needs to be at least 4MHz in order to use the
routines with Dallas digital thermometers.
Library Routines
Ow_Reset
Ow_Read
Ow_Write
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Ow_Reset
Prototype
char Ow_Reset(char *port, char pin);
Returns
Returns 0 if DS1820 is present, 1 if not present.
Description
Issues OneWire reset signal for DS1820. Parameters port and pin specify the location
of DS1820.
Requires
Works with Dallas DS1820 temperature sensor only.
Example
Ow_Reset(&PORTA, 5); // reset DS1820 connected to the RA5 pin
Ow_Read
Prototype
char Ow_Read(char *port, char pin);
Returns
Data read from an external device over the OneWire bus.
Description
Reads one byte of data via the OneWire bus.
Example
tmp = Ow_Read(&PORTA, 5);
Ow_Write
Prototype
void Ow_Write(char *port, char pin, char par);
Description
Writes one byte of data (argument par) via OneWire bus.
Example
Ow_Write(&PORTA, 5, 0xCC);
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Library Example
unsigned temp;
unsigned short
j;
void Display_Temperature(unsigned int temp) {
//...
}
void main() {
ADCON1 = 0xFF;
PORTA = 0xFF;
TRISA = 0x0F;
PORTB = 0;
TRISB = 0;
// Configure RA5 pin as digital I/O
// PORTA is input
// PORTB is output
// Initialize LCD on PORTB and prepare for output
do {
OW_Reset(&PORTA,5);
OW_Write(&PORTA,5,0xCC);
OW_Write(&PORTA,5,0x44);
Delay_us(120);
OW_Reset(&PORTA,5);
OW_Write(&PORTA,5,0xCC);
OW_Write(&PORTA,5,0xBE);
Delay_ms(400);
j = OW_Read(&PORTA,5);
temp = OW_Read(&PORTA,5);
temp <<= 8; temp += j;
Display_Temperature(temp);
Delay_ms(500);
// Onewire reset signal
// Issue command SKIP_ROM
// Issue command CONVERT_T
// Issue command SKIP_ROM
// Issue command READ_SCRATCHPAD
//
//
//
//
Get temperature LSB
Get temperature MSB
Form the result
Format and display result on LCD
} while (1);
}//~!
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Hardware Connection
125 C
7
VCC
VCC
R10
10K
VCC
11
DQ
RA5
12
13
14
VCC
GND
OSC1
OSC2
8 Mhz
PIC18F452
-50 C VCC
DS1820
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PS/2 Library
mikroC provides a library for communicating with common PS/2 keyboard.The
library does not utilize interrupts for data retrieval, and requires oscillator clock to
be 6MHz and above.
Library Routines
Ps2_Init
Ps2_Config
Ps2_Key_Read
Ps2_Init
Prototype
void Ps2_Init(unsigned short *port);
Description
Initializes port for work with PS/2 keyboard, with default pin settings. Port pin 0 is
Data line, and port pin 1 is Clock line.
You need to call either Ps2_Init or Ps2_Config before using other routines of PS/2
library.
Requires
Both Data and Clock lines need to be in pull-up mode.
Ps2_Config
Prototype
void Ps2_Config(char *port, char clock, char data);
Description
Initializes port for work with PS/2 keyboard, with custom pin settings. Parameters
data and clock specify pins of port for Data line and Clock line, respectively. Data
and clock need to be in range 0..7 and cannot point to the same pin.
You need to call either Ps2_Init or Ps2_Config before using other routines of PS/2
library.
Requires
Both Data and Clock lines need to be in pull-up mode.
Example
Ps2_Config(&PORTB, 2, 3);
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Ps2_Key_Read
Prototype
char Ps2_Key_Read(char *value, char *special, char *pressed);
Returns
Returns 1 if reading of a key from the keyboard was successful, otherwise 0.
Description
The function retrieves information about key pressed.
Parameter value holds the value of the key pressed. For characters, numerals, punctuation marks, and space, value will store the appropriate ASCII value. Routine “recognizes” the function of Shift and Caps Lock, and behaves appropriately.
Parameter special is a flag for special function keys (F1, Enter, Esc, etc). If key
pressed is one of these, special will be set to 1, otherwise 0.
Parameter pressed is set to 1 if the key is pressed, and 0 if released.
Requires
PS/2 keyboard needs to be initialized; see Ps2_Init or Ps2_Config.
Example
// Press Enter to continue:
do {
if (Ps2_Key_Read(&value, &special, &pressed)) {
if ((value == 13) && (special == 1)) break;
}
} while (1);
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Library Example
This simple example reads values of keys pressed on PS/2 keyboard and sends them via USART.
unsigned short keydata, special, down;
void main() {
CMCON = 0x07;
INTCON = 0;
Ps2_Init(&PORTA);
Delay_ms(100);
//
//
//
//
Disable analog comparators (comment this for PIC18)
Disable all interrupts
Init PS/2 Keyboard on PORTA
Wait for keyboard to finish
do {
if (Ps2_Key_Read(&keydata, &special, &down)) {
if (down && (keydata == 16)) {// Backspace
// ...do something with a backspace...
}
else if (down && (keydata == 13)) {// Enter
Usart_Write(13);
}
else if (down && !special && keydata) {
Usart_Write(keydata);
}
}
Delay_ms(10);
// debounce
} while (1);
}//~!
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PWM Library
CCP module is available with a number of PICmicros. mikroC provides library
which simplifies using PWM HW Module.
Note: Certain PICmicros with two or more CCP modules, such as P18F8520,
require you to specify the module you want to use. Simply append the number 1
or 2 to a Pwm. For example, Pwm2_Start(); Also, for the sake of backward compabitility with previous compiler versions and easier code management, MCU's
with multiple PWM modules have PWM library which is identical to PWM1 (i.e.
you can use PWM_Init() instead of PWM1_Init() to initialize CCP1).
Library Routines
Pwm_Init
Pwm_Change_Duty
Pwm_Start
Pwm_Stop
Pwm_Init
Prototype
void Pwm_Init(long freq);
Description
Initializes the PWM module with duty ratio 0. Parameter freq is a desired PWM frequency in Hz (refer to device data sheet for correct values in respect with Fosc).
Pwm_Init needs to be called before using other functions from PWM Library.
Requires
You need a CCP module in order to use this library. Check mikroC installation folder,
subfolder “Examples”, for alternate solutions.
Example
Pwm_Init(5000);
// Initialize PWM module at 5KHz
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Pwm_Change_Duty
Prototype
void Pwm_Change_Duty(char duty_ratio);
Description
Changes PWM duty ratio. Parameter duty_ratio takes values from 0 to 255, where 0
is 0%, 127 is 50%, and 255 is 100% duty ratio. Other specific values for duty ratio can
be calculated as (Percent*255)/100.
Requires
You need a CCP module on PORTC to use this library. To use this function, module
needs to be initalized – see Pwm_Init.
Example
Pwm_Change_Duty(192);
// Set duty ratio to 75%
Pwm_Start
Prototype
void Pwm_Start(void);
Description
Starts PWM.
Requires
You need a CCP module on PORTC to use this library. To use this function, module
needs to be initalized – see Pwm_Init.
Example
Pwm_Start();
Pwm_Stop
Prototype
void Pwm_Stop(void);
Description
Stops PWM.
Requires
You need a CCP module on PORTC to use this library. To use this function, module
needs to be initalized – see Pwm_Init.
Example
Pwm_Stop();
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Library Example
/*The example changes PWM duty ratio on pin RC2 continually. If LED is connected
to RC2, you can observe the gradual change of emitted light. */
char i = 0, j = 0;
void main() {
PORTC = 0xFF;
Pwm_Init(5000);
Pwm_Start();
// PORTC is output
// Initialize PWM module at 5KHz
// Start PWM
while (1) {
// Slow down, allow us to see the change on LED:
for (i = 0; i < 20; i++) Delay_us(500);
j++;
Pwm_Change_Duty(j);
// Change duty ratio
}
}
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Hardware Connection
11
12
13
8 Mhz
14
VCC
GND
OSC1
OSC2
17
PIC18F452
VCC
RC2
300R
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RS-485 Library
RS-485 is a multipoint communication which allows multiple devices to be connected to a single signal cable. mikroC provides a set of library routines to provide
you comfortable work with RS-485 system using Master/Slave architecture.
Master and Slave devices interchange packets of information, each of these packets containing synchronization bytes, CRC byte, address byte, and the data. Each
Slave has its unique address and receives only the packets addressed to it. Slave
can never initiate communication. It is programmer’s responsibility to ensure that
only one device transmits via 485 bus at a time.
RS-485 routines require USART module on PORTC. Pins of USART need to be
attached to RS-485 interface transceiver, such as LTC485 or similar. Pins of transceiver (Receiver Output Enable and Driver Outputs Enable) should be connected
to PORTC, pin 2 (check the figure at end of the chapter).
Note: Address 50 is the common address for all Slaves (packets containing
address 50 will be received by all Slaves). The only exceptions are Slaves with
addresses 150 and 169, which require their particular address to be specified in the
packet.
Note: Usart_Init() must be called before initializing RS485.
Library Routines
RS485Master_Init
RS485Master_Receive
RS485Master_Send
RS485Slave_Init
RS485Slave_Receive
RS485Slave_Send
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RS485Master_Init
Prototype
void Rs485master_Init(unsigned short * port, unsigned short pin);
Description
Initializes PIC MCU as Master in RS-485 communication.
Requires
USART HW module needs to be initialized. See USART_Init.
Example
RS485Master_Init(PORTC, 2);
RS485Master_Receive
Prototype
void RS485Master_Receive(char *data);
Description
Receives any message sent by Slaves. Messages are multi-byte, so this function must be
called for each byte received (see the example at the end of the chapter). Upon receiving
a message, buffer is filled with the following values:
data[0..2] is the message,
data[3] is number of message bytes received, 1–3,
data[4] is set to 255 when message is received,
data[5] is set to 255 if error has occurred,
data[6] is the address of the Slave which sent the message.
Function automatically adjusts data[4] and data[5] upon every received message.
These flags need to be cleared from the program.
Requires
MCU must be initialized as Master in RS-485 communication in order to be assigned an
address. See RS485Master_Init.
Example
unsigned short msg[8];
...
RS485Master_Receive(msg);
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RS485Master_Send
Prototype
void RS485Master_Send(char *data, char datalen, char address);
Description
Sends data from buffer to Slave(s) specified by address via RS-485; datalen is a
number of bytes in message (1 <= datalen <= 3).
Requires
MCU must be initialized as Master in RS-485 communication in order to be assigned an
address. See RS485Master_Init.
It is programmer’s responsibility to ensure (by protocol) that only one device sends data
via 485 bus at a time.
Example
unsigned short msg[8];
...
RS485Master_Send(msg, 3, 0x12);
RS485Slave_Init
Prototype
void Rs485slave_Init(unsigned short * port, unsigned short pin,
char address);
Description
Initializes MCU as Slave with a specified address in RS-485 communication. Slave
address can take any value between 0 and 255, except 50, which is common address
for all slaves.
Requires
USART HW module needs to be initialized. See USART_Init.
Example
RS485Slave_Init(PORTC, 2 ,160); // Initialize MCU as Slave with
address 160
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RS485Slave_Receive
Prototype
void RS485Slave_Receive(char *data);
Description
Receives message addressed to it. Messages are multi-byte, so this function must be
called for each byte received (see the example at the end of the chapter). Upon receiving
a message, buffer is filled with the following values:
data[0..2] is the message,
data[3] is number of message bytes received, 1–3,
data[4] is set to 255 when message is received,
data[5] is set to 255 if error has occurred,
data[6] is the address of the Slave which sent the message.
Function automatically adjusts data[4] and data[5] upon every received message.
These flags need to be cleared from the program.
Requires
MCU must be initialized as Slave in RS-485 communication in order to be assigned an
address. See RS485Slave_Init.
Example
unsigned short msg[8];
...
RS485Slave_Read(msg);
RS485Slave_Send
Prototype
void RS485Slave_Send(char *data, char datalen);
Description
Sends data from buffer to Master via RS-485; datalen is a number of bytes in message (1 <= datalen <= 3).
Requires
MCU must be initialized as Slave in RS-485 communication in order to be assigned an
address. See RS485Slave_Init.
It is programmer’s responsibility to ensure (by protocol) that only one device sends data
via 485 bus at a time.
Example
unsigned short msg[8];
...
RS485Slave_Send(msg, 2);
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Library Example
The example demonstrates working with PIC as Slave nod in RS-485 communication. PIC
receives only packets addressed to it (address 160 in our example), and general messsages with
target address 50. The received data is forwarded to PORTB, and sent back to Master.
unsigned short dat[8];
char i = 0, j = 0;
// buffer for receiving/sending messages
void interrupt() {
/* Every byte is received by RS485Slave_Read(dat);
If message is received without errors,
data[4] is set to 255 */
if (RCSTA.OERR) PORTD = 0x81;
RS485Slave_Read(dat);
}//~
void main() {
TRISB = 0;
TRISD = 0;
Usart_Init(9600);
// Initialize usart module
RS485Slave_Init(PORTC ,2 ,160);// Initialize MCU as Slave with address 160
PIE1.RCIE
= 1;
// Enable interrupt
INTCON.PEIE = 1;
//
on byte received
PIE2.TXIE
= 0;
//
via USART (RS485)
INTCON.GIE = 1;
PORTB = 0;
PORTD = 0;
dat[4] = 0;
// Ensure that msg received flag is 0
dat[5] = 0;
// Ensure that error flag is 0
do {
if (dat[5]) PORTD = 0xAA;
if (dat[4]) {
dat[4] = 0;
j = dat[3];
for (i = 1; i < j; i++)
PORTB = dat[--i];
dat[0]++;
RS485Slave_Write(dat, 1);
}
} while (1);
}//~!
// If there is error, set PORTD to $AA
// If message received:
//
Clear message received flag
//
Number of data bytes received
//
//
//
Output received data bytes
Increment received dat[0]
Send it back to Master
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Hardware Connection
Shielded pair
no longer than 300m
11
12
VCC
1
2
3
R0
Vcc
RE
B
DE
4
DI
13
14
8
8 Mhz
7
17
VCC
GND
OSC1
OSC2
PIC18F452
VCC
RC7
RC6
26
25
RC2
6
A
GND
5
LTC485
VCC
620R
1
2
3
4
R0
Vcc
RE
B
DE
A
DI
GND
8
7
6
5
620R
LTC485
4.7uF +
+
V+
C1C2+
+
C2-
4.7uF
VT2out
R2in
+
MAX232
C1+
4.7uF
Vcc
GND
T1 OUT
R1IN
PC
R1out
T1in
T2in
R2out
RTS
GND
4.7uF
TX
RX
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Software I2C Library
mikroC provides routines which implement software I²C. These routines are hardware independent and can be used with any MCU. Software I2C enables you to
use MCU as Master in I2C communication. Multi-master mode is not supported.
Note: This library implements time-based activities, so interrupts need to be disabled when using Soft I²C.
Library Routines
Soft_I2C_Config
Soft_I2C_Start
Soft_I2C_Read
Soft_I2C_Write
Soft_I2C_Stop
Soft_I2C_Config
Prototype
void Soft_I2C_Config(char *port, const char SDI, const char SD0,
const char SCK);
Description
Configures software I²C. Parameter port specifies port of MCU on which SDA and SCL
pins are located. Parameters SCL and SDA need to be in range 0–7 and cannot point at
the same pin.
Soft_I2C_Config needs to be called before using other functions from Soft I2C
Library.
Example
Soft_I2C_Config(PORTB, 1, 2);
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Soft_I2C_Start
Prototype
void Soft_I2C_Start(void);
Description
Issues START signal. Needs to be called prior to sending and receiving data.
Requires
Soft I²C must be configured before using this function. See Soft_I2C_Config.
Example
Soft_I2C_Start();
Soft_I2C_Read
Prototype
char Soft_I2C_Read(char ack);
Returns
Returns one byte from the slave.
Description
Reads one byte from the slave, and sends not acknowledge signal if parameter ack is 0,
otherwise it sends acknowledge.
Requires
START signal needs to be issued in order to use this function. See Soft_I2C_Start.
Example
tmp = Soft_I2C_Read(0); //Read data, send not-acknowledge signal
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Soft_I2C_Write
Prototype
char Soft_I2C_Write(char data);
Returns
Returns 0 if there were no errors.
Description
Sends data byte (parameter data) via I²C bus.
Requires
START signal needs to be issued in order to use this function. See Soft_I2C_Start.
Example
Soft_I2C_Write(0xA3);
Soft_I2C_Stop
Prototype
void Soft_I2C_Stop(void);
Description
Issues STOP signal.
Requires
START signal needs to be issued in order to use this function. See Soft_I2C_Start.
Example
Soft_I2C_Stop();
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Library Example
/* The example demonstrates use of Software I²C Library.
PIC MCU is connected (SCL, SDA pins) to PCF8583 RTC (real-time clock).
Program sends date data to RTC. */
void main() {
Soft_I2C_Config(&PORTD, 4,3);
// Initialize full master mode
Soft_I2C_Start();
Soft_I2C_Write(0xA0);
Soft_I2C_Write(0);
Soft_I2C_Write(0x80);
Soft_I2C_Write(0);
Soft_I2C_Write(0);
Soft_I2C_Write(0x30);
Soft_I2C_Write(0x11);
Soft_I2C_Write(0x30);
Soft_I2C_Write(0x08);
Soft_I2C_Stop();
//
//
//
//
//
//
//
//
//
//
//
Issue start signal
Address PCF8583
Start from word at address 0 (config word)
Write 0x80 to config. (pause counter...)
Write 0 to cents word
Write 0 to seconds word
Write 0x30 to minutes word
Write 0x11 to hours word
Write 0x24 to year/date word
Write 0x08 to weekday/month
Issue stop signal
Soft_I2C_Start();
Soft_I2C_Write(0xA0);
Soft_I2C_Write(0);
Soft_I2C_Write(0);
Soft_I2C_Stop();
//
//
//
//
//
Issue start signal
Address PCF8530
Start from word at address 0
Write 0 to config word (enable counting)
Issue stop signal
}//~!
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Software SPI Library
mikroC provides library which implement software SPI. These routines are hardware independent and can be used with any MCU. You can easily communicate
with other devices via SPI: A/D converters, D/A converters, MAX7219, LTC1290,
etc.
The library configures SPI to master mode, clock = 50kHz, data sampled at the
middle of interval, clock idle state low and data transmitted at low to high edge.
Note: These functions implement time-based activities, so interrupts need to be
disabled when using the library.
Library Routines
Soft_Spi_Config
Soft_Spi_Read
Soft_Spi_Write
Soft_Spi_Config
Prototype
void Soft_Spi_Config(char *port, const char SDI, const char SD0,
const char SCK);
Description
Configures and initializes software SPI. Parameter port specifies port of MCU on which
SDI, SDO, and SCK pins will be located. Parameters SDI, SDO, and SCK need to be in
range 0–7 and cannot point at the same pin.
Soft_Spi_Config needs to be called before using other functions from Soft SPI
Library.
Example
This will set SPI to master mode, clock = 50kHz, data sampled at the middle of interval,
clock idle state low and data transmitted at low to high edge. SDI pin is RB1, SDO pin
is RB2 and SCK pin is RB3:
Soft_Spi_Config(PORTB, 1, 2, 3);
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Soft_Spi_Read
Prototype
char Soft_Spi_Read(char buffer);
Returns
Returns the received data.
Description
Provides clock by sending buffer and receives data.
Requires
Soft SPI must be initialized and communication established before using this function.
See Soft_Spi_Config.
Example
tmp = Soft_Spi_Read(buffer);
Soft_Spi_Write
Prototype
void Soft_Spi_Write(char data);
Description
Immediately transmits data.
Requires
Soft SPI must be initialized and communication established before using this function.
See Soft_Spi_Config.
Example
Soft_Spi_Write(1);
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Library Example
This is a sample program which demonstrates the use of the Microchip's MCP4921 12-bit D/A converter
with PIC mcu's. This device accepts digital input (number from 0..4095) and transforms it to the output
voltage, ranging from 0..Vref. In this example the D/A is connected to PORTC and communicates with
PIC through the SPI. The reference voltage on the mikroElektronika's DAC module is 5 V. In this example, the entire DAC’s resolution range (12bit ? 4096 increments) is covered, meaning that you’ll need to
hold a button for about 7 minutes to get from mid-range to the end-of-range.
const char _CHIP_SELECT = 1, _TRUE = 0xFF;
unsigned value;
void InitMain() {
Soft_SPI_Config(&PORTB, 4,5,3);
TRISB &= ~(_CHIP_SELECT);
TRISC = 0x03;
}//~
// DAC increments (0..4095) --> output
void DAC_Output(unsigned valueDAC) {
char temp;
PORTB &= ~(_CHIP_SELECT);
temp = (valueDAC >> 8) & 0x0F;
temp |= 0x30;
Soft_Spi_Write(temp);
temp = valueDAC;
Soft_Spi_Write(temp);
PORTB |= _CHIP_SELECT;
}//~
// ClearBit(TRISC,CHIP_SELECT);
voltage (0..Vref)
//
//
//
//
//
ClearBit(PORTC,CHIP_SELECT);
Prepare hi-byte for transfer
It's a 12-bit number, so only
lower nibble of high byte is used
Prepare lo-byte for transfer
// SetBit(PORTC,CHIP_SELECT);
void main() {
InitMain();
DAC_Output(2048);
//
value = 2048;
//
while (1) {
//
if ((Button(&PORTC,0,1,1)==_TRUE) //
&& (value < 4095)) {
value++ ;
} else {
if ((Button(&PORTC,1,1,1)==_TRUE)
&& (value > 0)) {
value-- ;
}
}
DAC_Output(value);
//
Delay_ms(100);
//
}
}//~!
When program starts, DAC gives
the output in the mid-range
Main loop
Test button on B0 (increment)
// If RB0 is not active then test
//
RB1 (decrement)
Perform output
Slow down key repeat pace
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Software UART Library
mikroC provides library which implements software UART. These routines are
hardware independent and can be used with any MCU. You can easily communicate with other devices via RS232 protocol – simply use the functions listed
below.
Note: This library implements time-based activities, so interrupts need to be disabled when using Soft UART.
Library Routines
Soft_Uart_Init
Soft_Uart_Read
Soft_Uart_Write
Soft_Uart_Init
Prototype
void Soft_Uart_Init(unsigned short *port, unsigned short rx,
unsigned short tx, unsigned short baud_rate, char inverted);
Description
Initalizes software UART. Parameter port specifies port of MCU on which RX and TX
pins are located; parameters rx and tx need to be in range 0–7 and cannot point at the
same pin; baud_rate is the desired baud rate. Maximum baud rate depends on PIC’s
clock and working conditions. Parameter inverted, if set to non-zero value, indicates
inverted logic on output.
Soft_Uart_Init needs to be called before using other functions from Soft UART
Library.
Example
Soft_Uart_Init(PORTB, 1, 2, 9600, 0);
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Soft_Uart_Read
Prototype
unsigned short Soft_Uart_Read(unsigned short *error);
Returns
Returns a received byte.
Description
Function receives a byte via software UART. Parameter error will be zero if the
transfer was successful. This is a non-blocking function call, so you should test the
error manually (check the example below).
Requires
Soft UART must be initialized and communication established before using this function. See Soft_Uart_Init.
Example
// Here’s a loop which holds until data is received:
do
data = Soft_Uart_Read(&error);
while (error);
// Now we can work with it:
if (data) {...}
Soft_Uart_Write
Prototype
void Soft_Uart_Write(char data);
Description
Function transmits a byte (data) via UART.
Requires
Soft UART must be initialized and communication established before using this function. See Soft_Uart_Init.
Be aware that during transmission, software UART is incapable of receiving data – data
transfer protocol must be set in such a way to prevent loss of information.
Example
char some_byte = 0x0A;
...
Soft_Uart_Write(some_byte);
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Library Example
The example demonstrates simple data exchange via software UART. When PIC
MCU receives data, it immediately sends the same data back. If PIC is connected
to the PC (see the figure below), you can test the example from mikroC terminal
for RS232 communication, menu choice Tools > Terminal.
unsigned short data = 0, ro = 0;
unsigned short *er;
void main() {
er = &ro;
// Init (8 bit, 2400 baud rate, no parity bit, non-inverted logic)
Soft_Uart_Init(PORTB, 1, 2, 2400, 0);
do {
do {
data = Soft_Uart_Read(er);
} while (*er);
Soft_Uart_Write(data);
} while (1);
}//~!
// Receive data
// Send data via UART
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Sound Library
mikroC provides a Sound Library which allows you to use sound signalization in
your applications. You need a simple piezo speaker (or other hardware) on designated port.
Library Routines
Sound_Init
Sound_Play
Sound_Init
Prototype
void Sound_Init(char *port, char pin);
Description
Prepares hardware for output at specified port and pin. Parameter pin needs to be within
range 0–7.
Example
Sound_Init(PORTB, 2);
// Initialize sound on RB2
Sound_Play
Prototype
void Sound_Play(char period_div_10, unsigned num_of_periods);
Description
Plays the sound at the specified port and pin (see Sound_Init). Parameter period_div_10
is a sound period given in MCU cycles divided by ten, and generated sound lasts for a
specified number of periods (num_of_periods).
Requires
To hear the sound, you need a piezo speaker (or other hardware) on designated port.
Also, you must call Sound_Init to prepare hardware for output.
Example
To play sound of 1KHz: T = 1/f = 1ms = 1000 cycles @ 4MHz. This gives us our first
parameter: 1000/10 = 100. Play 150 periods like this:
Sound_Play(100, 150);
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Library Example
The example is a simple demonstration of how to use sound library for playing
tones on a piezo speaker. The code can be used with any MCU that has PORTB
and ADC on PORTA. Sound frequencies in this example are generated by reading
the value from ADC and using the lower byte of the result as base for T (f = 1/T).
int adcValue;
void main() {
PORTB = 0;
TRISB = 0;
INTCON = 0;
ADCON1 = 0x82;
TRISA = 0xFF;
Sound_Init(PORTB, 2);
//
//
//
//
//
//
Clear PORTB
PORTB is output
Disable all interrupts
Configure VDD as Vref, and analog channels
PORTA is input
Initialize sound on RB2
while (1) {
adcValue = ADC_Read(2);
Sound_Play(adcValue, 200);
}
// Play in loop:
//
Get lower byte from ADC
//
Play the sound
}
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SPI Library
SPI module is available with a number of PIC MCU models. mikroC provides a
library for initializing Slave mode and comfortable work with Master mode. PIC
can easily communicate with other devices via SPI: A/D converters, D/A converters, MAX7219, LTC1290, etc. You need PIC MCU with hardware integrated SPI
(for example, PIC16F877).
Note: Certain PICmicros with two SPI modules, such as P18F8722, require you to
specify the module you want to use. Simply append the number 1 or 2 to a Spi.
For example, Spi2_Write(); Also, for the sake of backward compabitility with
previous compiler versions and easier code management, MCU's with multiple
SPI modules have SPI library which is identical to SPI1 (i.e. you can use
SPI_Init() instead of SPI1_Init() for SPI operations).
Library Routines
Spi_Init
Spi_Init_Advanced
Spi_Read
Spi_Write
Spi_Init
Prototype
void Spi_Init(void);
Description
Configures and initializes SPI with default settings. SPI_Init_Advanced or
SPI_Init needs to be called before using other functions from SPI Library.
Default settings are: Master mode, clock Fosc/4, clock idle state low, data transmitted on
low to high edge, and input data sampled at the middle of interval.
For custom configuration, use Spi_Init_Advanced.
Requires
You need PIC MCU with hardware integrated SPI.
Example
Spi_Init();
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Spi_Init_Advanced
Prototype
void Spi_Init_Advanced(char master, char data_sample, char
clock_idle, char transmit_edge);
Description
Configures and initializes SPI. Spi_Init_Advanced or SPI_Init needs to be called
before using other functions of SPI Library.
Parameter mast_slav determines the work mode for SPI; can have the values:
MASTER_OSC_DIV4
MASTER_OSC_DIV16
MASTER_OSC_DIV64
MASTER_TMR2
SLAVE_SS_ENABLE
SLAVE_SS_DIS
//
//
//
//
//
//
Master
Master
Master
Master
Master
Master
clock=Fosc/4
clock=Fosc/16
clock=Fosc/64
clock source TMR2
Slave select enabled
Slave select disabled
The data_sample determines when data is sampled; can have the values:
DATA_SAMPLE_MIDDLE // Input data sampled in middle of interval
DATA_SAMPLE_END
// Input data sampled at the end of interval
Parameter clock_idle determines idle state for clock; can have the following values:
CLK_IDLE_HIGH
CLK_IDLE_LOW
// Clock idle HIGH
// Clock idle LOW
Parameter transmit_edge can have the following values:
LOW_2_HIGH
HIGH_2_LOW
// Data transmit on low to high edge
// Data transmit on high to low edge
Requires
You need PIC MCU with hardware integrated SPI.
Example
This will set SPI to master mode, clock = Fosc/4, data sampled at the middle of interval,
clock idle state low and data transmitted at low to high edge:
Spi_Init_Advanced(MASTER_OSC_DIV4, DATA_SAMPLE_MIDDLE,
CLK_IDLE_LOW, LOW_2_HIGH)
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Spi_Read
Prototype
char Spi_Read(char buffer);
Returns
Returns the received data.
Description
Provides clock by sending buffer and receives data at the end of period.
Requires
SPI must be initialized and communication established before using this function. See
Spi_Init_Advanced or Spi_Init.
Example
short take, buffer;
...
take = Spi_Read(buffer);
Spi_Write
Prototype
void Spi_Write(char data);
Description
Writes byte data to SSPBUF, and immediately starts the transmission.
Requires
SPI must be initialized and communication established before using this function. See
Spi_Init_Advanced or Spi_Init.
Example
Spi_Write(1);
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Library Example
The code demonstrates how to use SPI library functions. Assumed HW configuration is: max7219 (chip select pin) connected to RC1, and SDO, SDI, SCK pins are
connected to corresponding pins of max7219.
//------------------- Function Declarations
void max7219_init1();
//-------------------------------- F.D. end
char i;
void main() {
Spi_Init();
TRISC &= 0xFD;
max7219_init1();
for (i = 1; i <= 8u; i++) {
PORTC &= 0xFD;
Spi_Write(i);
Spi_Write(8 - i);
PORTC |= 2;
}
TRISB = 0;
PORTB = i;
}//~!
// Standard configuration
// Initialize
//
//
//
//
max7219
Select max7219
Send i to max7219 (digit place)
Send i to max7219 (digit)
Deselect max7219
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USART Library
USART hardware module is available with a number of PICmicros. mikroC
USART Library provides comfortable work with the Asynchronous (full duplex)
mode.You can easily communicate with other devices via RS232 protocol (for
example with PC, see the figure at the end of the topic – RS232 HW connection).
You need a PIC MCU with hardware integrated USART, for example PIC16F877.
Then, simply use the functions listed below.
Note: USART library functions support module on PORTB, PORTC, or PORTG,
and will not work with modules on other ports. Examples for PICmicros with
module on other ports can be found in “Examples” in mikroC installation folder.
Library Routines
Usart_Init
Usart_Data_Ready
Usart_Read
Usart_Write
Note: Certain PICmicros with two USART modules, such as P18F8520, require
you to specify the module you want to use. Simply append the number 1 or 2 to a
function name. For example, Usart_Write2(); Also, for the sake of backward
compabitility with previous compiler versions and easier code management,
MCU's with multiple USART modules have USART library which is identical to
USART1 (i.e. you can use Usart_Init() instead of Usart_Init1() for Usart
operations).
Usart_Init
Prototype
void Usart_Init(const long baud_rate);
Description
Initializes hardware USART module with the desired baud rate. Refer to the device data
sheet for baud rates allowed for specific Fosc. If you specify the unsupported baud rate,
compiler will report an error.
Usart_Init needs to be called before using other functions from USART Library.
Requires
You need PIC MCU with hardware USART.
Example
Usart_Init(2400);
// Establish communication at 2400 bps
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Usart_Data_Ready
Prototype
char Usart_Data_Ready(void);
Returns
Function returns 1 if data is ready or 0 if there is no data.
Description
Use the function to test if data is ready for transmission.
Requires
USART HW module must be initialized and communication established before using
this function. See Usart_Init.
Example
int receive;
...
// If data is ready, read it:
if (Usart_Data_Ready()) receive = Usart_Read;
Usart_Read
Prototype
char Usart_Read(void);
Returns
Returns the received byte. If byte is not received, returns 0.
Description
Function receives a byte via USART. Use the function Usart_Data_Ready to test if
data is ready first.
Requires
USART HW module must be initialized and communication established before using
this function. See Usart_Init.
Example
int receive;
...
// If data is ready, read it:
if (Usart_Data_Ready()) receive = Usart_Read;
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Usart_Write
Prototype
char Usart_Write(char data);
Description
Function transmits a byte (data) via USART.
Requires
USART HW module must be initialized and communication established before using
this function. See Usart_Init.
Example
int chunk;
...
Usart_Write(chunk);
/* send data chunk via USART */
Library Example
The example demonstrates simple data exchange via USART. When PIC MCU
receives data, it immediately sends the same data back. If PIC is connected to the
PC (see the figure below), you can test the example from mikroC terminal for
RS232 communication, menu choice Tools > Terminal.
unsigned short i;
void main() {
// Initialize USART module (8 bit, 2400 baud rate, no parity bit..)
Usart_Init(2400);
do {
if (Usart_Data_Ready()) {
i = Usart_Read();
Usart_Write(i);
}
} while (1);
}//~!
// If data is received
// Read the received data
// Send data via USART
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Hardware Connection
PC
6
RS-232
CON
9
1
CN3
SUB-D 9p
5
CONNECT
MCU TO PC
Receive
data (Rx)
SERIAL
CABLE
CONNECT
PC TO MCU
6
RS-232
CON
9
CN3
SUB-D 9p
8
4
9
5
1
2
7
3
5
6
1
Send
Data (Tx)
VCC
VCC
U6
13
R2 IN
T1 IN
10
1
E9
10uF
3
T2 IN
C1+
C1-
6
E10
10uF
15
VGND
MAX232
8
11
R1 IN
R1 OUT
R2 OUT
12
Rx
9
14
8 Mhz
T1 OUT
T2 OUT
C2+
7
VCC
GND
OSC1
OSC2
RC7
RC6
26
25
4
5
C2V+
11
12
13
14
PIC18F452
C18
100nF
E11
10uF
2
16
VCC
VCC
E12
10uF
Tx
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USB HID Library
Universal Serial Bus (USB) provides a serial bus standard for connecting a wide
variety of devices, including computers, cell phones, game consoles, PDAs, etc.
mikroC includes a library for working with human interface devices via Universal
Serial Bus. A human interface device or HID is a type of computer device that
interacts directly with and takes input from humans, such as the keyboard, mouse,
graphics tablet, and the like.
Library Routines
Hid_Enable
Hid_Read
Hid_Write
Hid_Disable
Hid_Enable
Prototype
void Hid_Enable(unsigned *readbuff, unsigned *writebuff);
Description
Enables USB HID communication. Parameters readbuff and writebuff are the Read
Buffer and the Write Buffer, respectively, which are used for HID communication.
This function needs to be called before using other routines of USB HID Library.
Example
Hid_Enable(&rd, &wr);
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Hid_Read
Prototype
unsigned short Hid_Read(void);
Returns
Number of characters in Read Buffer received from Host.
Description
Receives message from host and stores it in the Read Buffer. Function returns the number of characters received in Read Buffer.
Requires
USB HID needs to be enabled before using this function. See Hid_Enable.
Example
get = Hid_Read();
Hid_Write
Prototype
void Hid_Write(unsigned *writebuff, unsigned short len);
Description
Function sends data from wrbuff to host. Write Buffer is the same parameter as used in
initialization. Parameter len should specify a length of the data to be transmitted.
Requires
USB HID needs to be enabled before using this function. See Hid_Enable.
Example
Hid_Write(&wr, len);
Hid_Disable
Prototype
void Hid_Disable(void);
Description
Disables USB HID communication.
Requires
USB HID needs to be enabled before using this function. See Hid_Enable.
Example
Hid_Disable();
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Library Example
The following example continually sends sequence of numbers 0..255 to the PC via Universal
Serial Bus.
unsigned short m, k;
unsigned short userRD_buffer[64];
unsigned short userWR_buffer[64];
void interrupt() {
asm CALL _Hid_InterruptProc
asm nop
}//~
void Init_Main() {
// Disable all interrupts
// Disable GIE, PEIE, TMR0IE, INT0IE,RBIE
INTCON = 0;
INTCON2 = 0xF5;
INTCON3 = 0xC0;
// Disable Priority Levels on interrupts
RCON.IPEN = 0;
PIE1 = 0; PIE2 = 0; PIR1 = 0; PIR2 = 0;
// Configure all ports with analog function as digital
ADCON1 |= 0x0F;
// Ports Configuration
TRISA = 0; TRISB = 0; TRISC = 0xFF; TRISD = 0xFF; TRISE = 0x07;
LATA = 0; LATB = 0; LATC = 0; LATD = 0; LATE = 0;
// Clear user RAM
// Banks [00 .. 07] ( 8 x 256 = 2048 Bytes )
asm {
LFSR
FSR0, 0x000
MOVLW
0x08
CLRF
POSTINC0, 0
CPFSEQ
FSR0H, 0
BRA
$ - 2
}
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// Timer 0
T0CON = 0x07;
TMR0H = (65536-156) >> 8;
TMR0L = (65536-156) & 0xFF;
INTCON.T0IE = 1;
// Enable T0IE
T0CON.TMR0ON = 1;
}//~
/** Main Program Routine **/
void main() {
Init_Main();
Hid_Enable(&userRD_buffer, &userWR_buffer);
do {
for (k = 0; k < 255; k++) {
// Prepare send buffer
userWR_buffer[0] = k;
// Send the number via USB
Hid_Write(&userWR_buffer, 1);
}
} while (1);
Hid_Disable();
}//~!
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HW Connection
MCLR
RB7
RA0
RB6
RA1
RB5
RA2
RB4
RA4
RA5
RE0
RE1
VCC
11
12
RE2
VDD
VSS
13
14
8 Mhz
OSC1
OSC2
RC0
100nF
RB3
RB2
RB1
RB0
VDD
VSS
RD7
RD6
RD5
RD4
VCC
RC7
RC6
VCC
RC2
RC5
D-
Vusb
RC4
D+
RD0
RD3
GND
RD1
RD2
RC1
100nF
PIC18F4550
RA3
USB
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Util Library
Util library contains miscellaneous routines useful for project development.
Button
Prototype
char Button(char *port, char pin, char time, char active_state);
Returns
Returns 0 or 255.
Description
Function eliminates the influence of contact flickering upon pressing a button (debouncing).
Parameter port specifies the location of the button; parameter pin is the pin number on
designated port and goes from 0..7; parameter time is a debounce period in milliseconds; parameter active_state can be either 0 or 1, and it determines if the button is
active upon logical zero or logical one.
Example
Example reads RB0, to which the button is connected; on transition from 1 to 0 (release
of button), PORTD is inverted:
do {
if (Button(&PORTB, 0, 1, 1)) oldstate = 1;
if (oldstate && Button(&PORTB, 0, 1, 0)) {
PORTD = ~PORTD;
oldstate = 0;
}
} while(1);
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ANSI C Ctype Library
mikroC provides a set of standard ANSI C library functions for testing and mapping characters.
Note: Not all of the standard functions have been included. Functions have been
implemented according to the ANSI C standard, but certain functions have been
modified in order to facilitate PIC programming.
Library Routines
isalnum
isalpha
iscntrl
isdigit
isgraph
islower
isprint
ispunct
isspace
isupper
isxdigit
toupper
tolower
isalnum
Prototype
char isalnum(char character);
Description
Function returns 1 if the character is alphanumeric (A-Z, a-z, 0-9), otherwise returns
zero.
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isalpha
Prototype
char isalpha(char character);
Description
Function returns 1 if the character is alphabetic (A-Z, a-z), otherwise returns zero.
iscntrl
Prototype
char iscntrl(char character);
Description
Function returns 1 if the character is a control character or delete (decimal 0-31 and
127), otherwise returns zero.
isdigit
Prototype
char isdigit(char character);
Description
Function returns 1 if the character is a digit (0-9), otherwise returns zero.
isgraph
Prototype
char isgraph(char character);
Description
Function returns 1 if the character is a printable character, excluding the space (decimal 32), otherwise returns zero.
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islower
Prototype
char islower(char character);
Description
Function returns 1 if the character is a lowercase letter (a-z), otherwise returns zero.
isprint
Prototype
char isprint(char character);
Description
Function returns 1 if the character is printable (decimal 32-126), otherwise returns
zero.
ispunct
Prototype
char ispunct(char character);
Description
Function returns 1 if the character is punctuation (decimal 32-47, 58-63, 91-96, 123126), otherwise returns zero.
isspace
Prototype
char isspace(char character);
Description
Function returns 1 if the character is white space (space, CR, HT, VT, NL, FF), otherwise returns zero.
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isupper
Prototype
char isupper(char character);
Description
Function returns 1 if the character is an uppercase letter (A-Z), otherwise returns 0.
isxdigit
Prototype
char isxdigit(char character);
Description
Function returns 1 if the character is a hex digit (0-9, A-F, a-f), otherwise returns
zero.
toupper
Prototype
char toupper(int character);
Description
If the character is a lowercase letter (a-z), function returns an uppercase letter.
Otherwise, function returns an unchanged input parameter.
tolower
Prototype
char tolower(int character);
Description
If the character is an uppercase letter (A-Z), function returns a lowercase letter.
Otherwise, function returns an unchanged input parameter.
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ANSI C Math Library
mikroC provides a set of standard ANSI C library functions for floating point
math handling.
Note: Functions have been implemented according to the ANSI C standard, but
certain functions have been modified in order to facilitate PIC programming.
Library Routines
acos
asin
atan
atan2
ceil
cos
cosh
exp
fabs
floor
frexp
ldexp
log
log10
modf
pow
sin
sinh
sqrt
tan
tanh
acos
Prototype
double acos(double x);
Description
Function returns the arc cosine of parameter x; that is, the value whose cosine is x.
Input parameter x must be between -1 and 1 (inclusive). The return value is in radians,
between 0 and pi (inclusive).
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asin
Prototype
double asin(double x);
Description
Function returns the arc sine of parameter x; that is, the value whose sine is x. Input
parameter x must be between -1 and 1 (inclusive). The return value is in radians,
between -pi/2 and pi/2 (inclusive).
atan
Prototype
double atan(double x);
Description
Function computes the arc tangent of parameter x; that is, the value whose tangent is x.
The return value is in radians, between -pi/2 and pi/2 (inclusive).
atan2
Prototype
double atan2(double y, double x);
Description
This is the two argument arc tangent function. It is similar to computing the arc tangent
of y/x, except that the signs of both arguments are used to determine the quadrant of
the result, and x is permitted to be zero. The return value is in radians, between -pi and
pi (inclusive).
ceil
Prototype
double ceil(double num);
Description
Function returns value of parameter num rounded up to the next whole number.
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cos
Prototype
double cos(double x);
Description
Function returns the cosine of x in radians. The return value is from -1 to 1.
cosh
Prototype
double cosh(double x);
Description
Function returns the hyperbolic cosine of x, defined mathematically as (ex+e-x)/2. If
the value of x is too large (if overflow occurs), the function fails.
exp
Prototype
double exp(double x);
Description
Function returns the value of e — the base of natural logarithms — raised to the power
of x (i.e. ex).
fabs
Prototype
double fabs(double num);
Description
Function returns the absolute (i.e. positive) value of num.
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floor
Prototype
double floor(double num);
Description
Function returns value of parameter num rounded down to the nearest integer.
frexp
Prototype
double frexp(double num, int *n);
Description
Function splits a floating-point value num into a normalized fraction and an integral
power of 2. Return value is the normalized fraction, and the integer exponent is stored
in the object pointed to by n.
ldexp
Prototype
double ldexp(double num, int n);
Description
Function returns the result of multiplying the floating-point number num by 2 raised to
the power exp (i.e. returns x*2n).
log
Prototype
double log(double x);
Description
Function returns the natural logarithm of x (i.e. loge(x)).
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log10
Prototype
double log10(double x);
Description
Function returns the base-10 logarithm of x (i.e. log10(x)).
modf
Prototype
double modf(double num, double *whole);
Description
Function returns the signed fractional component of num, placing its whole number
component into the variable pointed to by whole.
pow
Prototype
double pow(double x, double y);
Description
Function returns the value of x raised to the power of y (i.e. xy). If the x is negative,
function will automatically cast the y into unsigned long.
sin
Prototype
double sin(double x);
Description
Function returns the sine of x in radians. The return value is from -1 to 1.
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sinh
Prototype
double sinh(double x);
Description
Function returns the hyperbolic sine of x, defined mathematically as (ex-e-x)/2. If the
value of x is too large (if overflow occurs), the function fails.
sqrt
Prototype
double sqrt(double num);
Description
Function returns the non negative square root of num.
tan
Prototype
double tan(double x);
Description
Function returns the tangent of x in radians. The return value spans the allowed range of
floating point in mikroC.
tanh
Prototype
double tanh(double x);
Description
Function returns the hyperbolic tangent of x, defined mathematically as
sinh(x)/cosh(x).
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ANSI C Stdlib Library
mikroC provides a set of standard ANSI C library functions of general utility.
Note: Not all of the standard functions have been included. Functions have been
implemented according to the ANSI C standard, but certain functions have been
modified in order to facilitate PIC programming.
Library Routines
abs
atof
atoi
atol
div
ldiv
labs
max
min
rand
srand
xtoi
abs
Prototype
int abs(int num);
Description
Function returns the absolute (i.e. positive) value of num.
atof
Prototype
double atof(char *s)
Description
Function converts the input string s into a double precision value, and returns the value.
Input string s should conform to the floating point literal format, with an optional whitespace at the beginning. The string will be processed one character at a time, until the
function reaches a character which it doesn’t recognize (this includes a null character).
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atoi
Prototype
int atoi(char *s);
Description
Function converts the input string s into an integer value, and returns the value. Input
string s should consist exclusively of decimal digits, with an optional whitespace and a
sign at the beginning. The string will be processed one character at a time, until the
function reaches a character which it doesn’t recognize (this includes a null character).
atol
Prototype
long atol(char *s)
Description
Function converts the input string s into a long integer value, and returns the value.
Input string s should consist exclusively of decimal digits, with an optional whitespace
and a sign at the beginning. The string will be processed one character at a time, until
the function reaches a character which it doesn’t recognize (this includes a null character).
div
Prototype
div_t div(int numer, int denom);
Description
Function computes the result of the division of the numerator numer by the denominator
denom; function returns a structure of type div_t comprising quotient (quot) and
remainder (rem).
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ldiv
Prototype
ldiv_t ldiv(long numer, long denom);
Description
Function is similar to the div function, except that the arguments and the result structure members all have type long.
Function computes the result of the division of the numerator numer by the denominator
denom; function returns a structure of type div_t comprising quotient (quot) and
remainder (rem).
labs
Prototype
long labs(long num);
Description
Function returns the absolute (i.e. positive) value of a long integer num.
max
Prototype
int max(int a, int b);
Description
Function returns greater of the two integers, a and b.
min
Prototype
int min(int a, int b);
Description
Function returns lower of the two integers, a and b.
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rand
Prototype
int rand(void);
Description
Function returns a sequence of pseudo-random numbers between 0 and 32767. Function
will always produce the same sequence of numbers unless srand() is called to seed the
starting point.
srand
Prototype
void srand(unsigned seed);
Description
Function uses the seed as a starting point for a new sequence of pseudo-random numbers to be returned by subsequent calls to rand(). No values are returned by this function.
xtoi
Prototype
int xtoi(char *s);
Description
Function converts the input string s consisting of hexadecimal digits into an integer
value. Input parametes s should consist exclusively of hexadecimal digits, with an
optional whitespace and a sign at the beginning. The string will be processed one character at a time, until the function reaches a character which it doesn’t recognize (this
includes a null character).
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ANSI C String Library
mikroC provides a set of standard ANSI C library functions useful for manipulating strings and arrays of char.
Note: Not all of the standard functions have been included. Functions have been
implemented according to the ANSI C standard, but certain functions have been
modified in order to facilitate PIC programming.
Library Routines
memcmp
memcpy
memmove
memset
memchr
strcat
strchr
strcmp
strcpy
strlen
strncat
strncpy
strspn
strcspn
strncmp
strpbrk
strrchr
strstr
strtok
memcmp
Prototype
int *memcmp(void *s1, void *s2, int n);
Description
Function compares the first n characters of objects pointed to by s1 and s2, and returns
zero if the objects are equal, or returns a difference between the first differing characters
(in a left-to-right evaluation). Accordingly, the result is greater than zero if the object
pointed to by s1 is greater than the object pointed to by s2, and vice versa.
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memcpy
Prototype
void *memcpy(void *s1, void *s2, int n);
Description
Function copies n characters from the object pointed to by s2 into the object pointed to
by s1. Objects may not overlap. Function returns the value of s1.
memmove
Prototype
void *memmove(void *s1, void *s2, int n);
Description
Function copies n characters from the object pointed to by s2 into the object pointed to
by s1. Unlike with memcpy(), memory areas s1 and s2 may overlap. Function returns
the value of s1.
memset
Prototype
void *memset(void *s, int c, int n);
Description
Function copies the value of character c (converted to char) into each of the first n
characters of the object pointed by s. Function returns the value of s.
memchr
Prototype
void * memchr(void *p, unsigned int n, unsigned int v);
Description
Function locates the first occurrence of byte v in the initial n bytes of memory area starting at the address p. Function returns the offset of this occurrence from the memory
address p or $FFFF if the v was not found.
For parameter p you can use either a numerical value (literal/variable/constant) indicating memory address or a dereferenced value of an object, for example @mystring or
@PORTB.
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strcat
Prototype
char *strcat(char *s1, char *s2);
Description
Function appends the string s2 to the string s1, overwriting the null character at the end
of s1. Then, a terminating null character is added to the result. Strings may not overlap,
and s1 must have enough space to store the result. Function returns a resulting string
s1.
strchr
Prototype
char *strchr(char *s, char c);
Description
Function locates the first occurrence of character c in the string s. Function returns a
pointer to the c, or a null pointer if c does not occur in s. The terminating null character
is considered to be a part of the string.
strcmp
Prototype
char strcmp(char *s1, char *s2);
Description
Function compares strings s1 and s2, and returns zero if the strings are equal, or returns
a difference between the first differing characters (in a left-to-right evaluation).
Accordingly, the result is greater than zero if s1 is greater than s2, and vice versa.
strcpy
Prototype
char *strcpy(char *s1, char *s2);
Description
Function copies the string s2 into the string s1. If successful, function returns s1. The
strings may not overlap.
strlen
Prototype
unsigned strlen(char *s);
Description
Function returns the length of the string s (the terminating null character does not count
against string’s length).
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strncat
Prototype
char *strncat(char *s1, char *s2, int n);
Description
Function appends not more than n characters from the string s2 to s1. The initial character of s2 overwrites the null character at the end of s1. A terminating null character is
always appended to the result. Function returns s1.
strncpy
Prototype
char *strncpy(char *s1, char *s2, int n);
Description
Function copies not more than n characters from string s2 to s1. The strings may not
overlap. If s2 is shorter than n characters, then s1 will be padded out with null characters to make up the difference. Function returns the resulting string s1.
strspn
Prototype
int strspn(char *s1, char *s2);
Description
Function returns the length of the maximum initial segment of s1 which consists entirely of characters from s2. The terminating null character character at the end of the string
is not compared.
strcspn
Prototype
char strcspn(char * s1, char * s2);
Description
The strcspn function computes the length of the maximum initial segment of the string
pointed to by s1 which consists entirely of characters not from the string pointed to by
s2.Function returns the length of the segment.
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strncmp
Prototype
int strncmp(char * s1, char * s2, char len);
Description
Function lexicographically compares the first n bytes of the strings s1 and s2 and returns
a value indicating their relationship:
Value
< 0
= 0
> 0
Meaning
s1 "less than" s2
s1 "equal to" s2
s1 "greater than" s2
The value returned by function is determined by the difference between the values of the
first pair of bytes that differ in the strings being compared (within first n bytes).
strpbrk
Prototype
char * strpbrk(char * s1, char * s2);
Description
Function searches s1 for the first occurrence of any character from the string s2. The
null terminator is not included in the search. Function returns an index of the matching
character in s1. If s1 contains no characters from s2, function returns $FF.
strpbrk
Prototype
char * strrchr(char * ptr, unsigned int chr);
Description
Function searches the string ptr for the last occurrence of character ch. The null character terminating ptr is not included in the search. Function returns an index of the last ch
found in ptr; if no matching character was found, function returns $FF.
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strstr
Prototype
char * strstr(char * s1, char * s2);
Description
Function locates the first occurrence of the string s2 in the string s1 (excluding the terminating null character).
Function returns a number indicating the position of the first occurrence of s2 in s1; if
no string was found, function returns $FF. If s2 is a null string, the function returns 0.
strtok
Prototype
char * strtok(char * s1, char * s2);
Returns
The strtok function returns a pointer to the first character of a token, or a null pointer if
there is no token.
Description
A sequence of calls to the strtok function breaks the string pointed to by s1 into a
sequence of tokens, each of which is delimited by a character from the string pointed to
by s2. The first call in the sequence has s1 as its first argument, and is followed by calls
with a null pointer as their first argument. The separator string pointed to by s2 may be
different from call to call.
The first call in the sequence searches the string pointed to by s1 for the first character
that is not contained in the current separator string pointed to by s2. If no such character
is found, then there are no tokens in the string pointed to by s1 and the strtok function
returns a null pointer. If such character is found, it is the start of the first token.
The strtok function then searches from there for a character that is contained in the current separator string. If no such character is found, the current token extends to the end
of the string pointed to by s1, and subsequent searches for a token will return a null
pointer. If such a character is found, it is overwritten by a null character, which terminates the current token. The strtok function saves a pointer to the following character,
from which the next search for a token will start.
Each subsequent call, with a null pointer as the value of the first argument, starts
searching from the saved pointer and behaves as described above.
Example
char x[10] ;
void main(){
strcpy(x, strtok("mikroEl", "Ek"));
strcpy(x, strtok(0, "kE"));
}
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Conversions Library
mikroC Conversions Library provides routines for converting numerals to strings,
and routines for BCD/decimal conversions.
Library Routines
You can get text representation of numerical value by passing it to one of the following routines:
ByteToStr
ShortToStr
WordToStr
IntToStr
LongToStr
FloatToStr
Following functions convert decimal values to BCD (Binary Coded Decimal) and
vice versa:
Bcd2Dec
Dec2Bcd
Bcd2Dec16
Dec2Bcd16
ByteToStr
Prototype
void ByteToStr(unsigned short number, char *output);
Description
Function creates an output string out of a small unsigned number (numerical value
less than 0x100). Output string has fixed width of 3 characters; remaining positions on
the left (if any) are filled with blanks.
Example
unsigned short t = 24;
char txt[4];
//...
ByteToStr(t, txt); // txt is " 24" (one blank here)
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ShortToStr
Prototype
void ShortToStr(short number, char *output);
Description
Function creates an output string out of a small signed number (numerical value less
than 0x100). Output string has fixed width of 4 characters; remaining positions on the
left (if any) are filled with blanks.
Example
short t = -24;
char txt[5];
//...
ByteToStr(t, txt);
// txt is " -24" (one blank here)
WordToStr
Prototype
void WordToStr(unsigned number, char *output);
Description
Function creates an output string out of an unsigned number (numerical value of
unsigned type). Output string has fixed width of 5 characters; remaining positions on
the left (if any) are filled with blanks.
Example
unsigned t = 437;
char txt[6];
//...
WordToStr(t, txt);
// txt is "
437" (two blanks here)
IntToStr
Prototype
void IntToStr(int number, char *output);
Description
Function creates an output string out of a signed number (numerical value of int
type). Output string has fixed width of 6 characters; remaining positions on the left (if
any) are filled with blanks.
Example
int j = -4220;
char txt[7];
//...
IntToStr(j, txt);
// txt is " -4220" (one blank here)
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LongToStr
Prototype
void LongToStr(long number, char *output);
Description
Function creates an output string out of a large signed number (numerical value of
long type). Output string has fixed width of 11 characters; remaining positions on the
left (if any) are filled with blanks.
Example
long jj = -3700000;
char txt[12];
//...
LongToStr(jj, txt);
// txt is "
-3700000" (three blanks here)
FloatToStr
Prototype
void FloatToStr(float number, char *output);
Description
Function creates an output string out of a floating-point number. The output string
contains a normalized format of the number (mantissa between 0 and 1) with sign at the
first position. Mantissa has fixed format of six digits, 0.ddddd; i.e. there will always be
5 digits following the dot. The output string must be at least 13 characters long.
Example
float ff = -374.2;
char txt[13];
//...
FloatToStr(ff, txt);
// txt is "-0.37420e3"
Bcd2Dec
Prototype
unsigned short Bcd2Dec(unsigned short bcdnum);
Returns
Returns converted decimal value.
Description
Converts 8-bit BCD numeral bcdnum to its decimal equivalent.
Example
unsigned short a;
...
a = Bcd2Dec(0x52);
// equals 52
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Dec2Bcd
Prototype
unsigned short Dec2Bcd(unsigned short decnum);
Returns
Returns converted BCD value.
Description
Converts 8-bit decimal value decnum to BCD.
Example
unsigned short a;
...
a = Dec2Bcd(52); // equals 0x52
Bcd2Dec16
Prototype
unsigned Bcd2Dec16(unsigned bcdnum);
Returns
Returns converted decimal value.
Description
Converts 16-bit BCD numeral bcdnum to its decimal equivalent.
Example
unsigned a;
...
a = Bcd2Dec16(1234);
// equals 4660
Dec2Bcd16
Prototype
unsigned Dec2Bcd(unsigned decnum);
Returns
Returns converted BCD value.
Description
Converts 16-bit decimal value decnum to BCD.
Example
unsigned a;
...
a = Dec2Bcd16(4660);
// equals 1234
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Trigonometry Library
mikroC implements fundamental trigonometry functions. These functions are
implemented as lookup tables, and return the result as integer, multiplied by 1000
and rounded up.
Library Routines
SinE3
CosE3
SinE3
Prototype
int SinE3(unsigned angle_deg);
Returns
Function returns the sine of input parameter, multiplied by 1000 (1E3) and rounded up
to the nearest integer. The range of return values is from -1000 to 1000.
Description
Function takes parameter angle_deg which represents angle in degrees, and returns its
sine multiplied by 1000 and rounded up to the nearest integer. The function is implemented as a lookup table; maximum error obtained is ±1.
Example
res = SinE3(45);
// result is 707
CosE3
Prototype
int CosE3(unsigned angle_deg);
Returns
Function returns the cosine of input parameter, multiplied by 1000 (1E3) and rounded
up to the nearest integer. The range of return values is from -1000 to 1000.
Description
Function takes parameter angle_deg which represents angle in degrees, and returns its
cosine multiplied by 1000 and rounded up to the nearest integer. The function is implemented as a lookup table; maximum error obtained is ±1.
Example
res = CosE3(196);
// result is -193
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Sprint Library
Library for sprint functions.
Note: In addition to ANSI C standard mikroC provides limited versions sprinti,
sprintlt that take a less ROM,RAM and may be convinient in some cases for PIC.
Library Routines
sprintf
sprintl
sprinti
sprintf
Description:
Function formats a series of strings and numeric values and stores the resulting
string in buffer.
Note: format string must be in the CONST area. sprintf function is not supported
for p12 and p16 PIC MCU families.
The fmtstr argument is a format string and may be composed of characters, escape
sequences, and format specifications. Ordinary characters and escape sequences
are copied to the buffer in the order in which they are interpreted. Format specifications always begin with a percent sign (%) and require additional arguments to
be included in the function call.
The format string is read from left to right. The first format specification encountered references the first argument after fmtstr and converts and outputs it using
the format specification. The second format specification accesses the second
argument after fmtstr, and so on. If there are more arguments than format specifications, the extra arguments are ignored. Results are unpredictable if there are not
enough arguments for the format specifications. Format specifications have the
following format:
% [flags] [width] [.precision] [{ h | l | L }] conversion_type
Each field in the format specification can be a single character or a number which
specifies a particular format option. The conversion_type field is where a single
character specifies that the argument is interpreted as a character, a string, a number, or a pointer, as shown in the following table.
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Argument Type
Conversion Type
Output Format
d
int
Signed decimal number
u
unsigned int
Unsigned decimal number
o
unsigned int
Unsigned octal number
x
unsigned int
Unsigned hexadecimal number using
0123456789ABCEDF
X
double
Floating-point number using the format []dddd.dddd
e
double
Floating-point number using the format []d.dddde[-]dd
E
double
Floating-point number using the format []d.ddddE[-]dd
g
double
Floating-point number using either e or f
format, whichever is more compact for the
specified value and precision
c
int
The int is converted to an unsigned char, and
the resulting character is written
s
char *
String with a terminating null character
p
void *
Pointer value, the X format is used
%
none
A % is written. No argument is converted. The
complete conversion specification shall be
%%.
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The flags field is where a single character is used to justify the output and to print
+/- signs and blanks, decimal points, and octal and hexadecimal prefixes, as shown
in the following table.
Meaning
Flags
-
Left justify the output in the specified field width.
+
Prefix the output value with a + or - sign if the output is a signed type.
space (' ')
Prefix the output value with a blank if it is a signed positive value.
Otherwise, no blank is prefixed
#
Prefixes a non-zero output value with 0, 0x, or 0X when used with o, x,
and X field types, respectively. When used with the e, E, f, g, and G
field types, the # flag forces the output value to include a decimal point.
The # flag is ignored in all other cases.
*
Ignore format specifier.
The width field is a non-negative number that specifies the minimum number of
characters printed. If the number of characters in the output value is less than
width, blanks are added on the left or right (when the - flag is specified) to pad to
the minimum width. If width is prefixed with a 0, zeros are padded instead of
blanks. The width field never truncates a field. If the length of the output value
exceeds the specified width, all characters are output.
The precision field is a non-negative number that specifies the number of characters to print, the number of significant digits, or the number of decimal places. The
precision field can cause truncation or rounding of the output value in the case of
a floating-point number as specified in the following table.
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Meaning of precision field
d, u, o, x, X
The precision field is where you specify the minimum number of digits
that will be included in the output value. Digits are not truncated if the
number of digits in the argument exceeds that defined in the precision
field. If the number of digits in the argument is less than the precision
field, the output value is padded on the left with zeros.
f
The precision field is where you specify the number of digits to the right
of the decimal point. The last digit is rounded.
e, E
The precision field is where you specify the number of digits to the right
of the decimal point. The last digit is rounded.
g
The precision field is where you specify the maximum number of significant digits in the output value.
c, C
s
The precision field has no effect on these field types.
The precision field is where you specify the maximum number of characters in the output value. Excess characters are not output.
The optional characters h and l or L may immediately precede the conversion_type
to respectively specify short or long versions of the integer types d, i, u, o, x, and
X.
You must ensure that the argument type matches that of the format specification.
You can use type casts to ensure that the proper type is passed to sprintf.
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sprintl
Prototype
int sprintl (
char *buffer,
const char *fmtstr,
... );
/* storage buffer */
/* format string */
/* additional arguments */
Returns
Function returns the number of characters actually written to buffer.
Description
Same as sprintf, except it doesn't support float-type numbers.
sprinti
Prototype
int sprinti (
char *buffer,
const char *fmtstr,
... );
/* storage buffer */
/* format string */
/* additional arguments */
Returns
Function returns the number of characters actually written to buffer.
Description
Same as sprintl, except it doesn't support long integer type numbers.
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SPI Graphic LCD Library
mikroC provides a library for operating the Graphic LCD 128x64 via SPI. These
routines work with the common GLCD 128x64 (samsung ks0108).
Note: Be sure to designate port with GLCD as output, before using any of the following library procedures or functions.
Important: When using SPI Library routines, you are required to specify the actual SPI module, either SPI1 or SPI2 in Spi_Glcd_Init.
Note: SPI_Init() must be called before initializing SPI GLCD.
Library Routines
Basic routines:
Spi_Glcd_Init
Spi_Glcd_Disable
Spi_Glcd_Set_Side
Spi_Glcd_Set_Page
Spi_Glcd_Set_X
Spi_Glcd_Read_Data
Spi_Glcd_Write_Data
Advanced routines:
Spi_Glcd_Fill
Spi_Glcd_Dot
Spi_Glcd_Line
Spi_Glcd_V_Line
Spi_Glcd_H_Line
Spi_Glcd_Rectangle
Spi_Glcd_Box
Spi_Glcd_Circle
Spi_Glcd_Set_Font
Spi_Glcd_Write_Char
Spi_Glcd_Write_Text
Spi_Glcd_Image
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Spi_Glcd_Init
Prototype
void SPI_Glcd_Init(char DeviceAddress, unsigned int * rstport,
unsigned int rstpin, unsigned int * csport, unsigned int cspin);
Description
Initializes Graphic LCD 128x64 via SPI. RstPort and RstPin - Sets pin connected on
reset pin of spi expander. CSPort and CSPin - Sets pin connected on CS pin of spi
expander. device address - address of spi expander (hardware setting of A0, A1 and
A2 pins (connected on VCC or GND) on spi expander).
Requires
Note: SPI_Init() must be called before initializing SPI GLCD.
This procedure needs to be called before using other routines of SPI GLCD library.
Example
Spi_Glcd_Init(0,&PORTC, 0, &PORTC, 1);
Spi_Glcd_Set_Side
Prototype
void SPI_Glcd_Set_Side(char x_pos);
Description
Selects side of GLCD, left or right. Parameter x specifies the side: values from 0 to 63
specify the left side, and values higher than 64 specify the right side. Use the functions
Spi_Glcd_Set_Side, Spi_Glcd_Set_X, and Spi_Glcd_Set_Page to specify an
exact position on GLCD. Then, you can use Spi_Glcd_Write_Data or
Spi_Glcd_Read_Data on that location.
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_Select_Side(0);
Spi_Glcd_Select_Side(10);
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Spi_Glcd_Set_Page
Prototype
void Spi_Glcd_Set_Page(char page);
Description
Selects page of GLCD, technically a line on display; parameter page can be 0..7.
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_Set_Page(5);
Spi_Glcd_Set_X
Prototype
void SPI_Glcd_Set_X(char x_pos);
Description
Positions to x dots from the left border of GLCD within the given page.
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_Set_X(25);
Spi_Glcd_Read_Data
Prototype
char Spi_Glcd_Read_Data();
Returns
One word from the GLCD memory.
Description
Reads data from from the current location of GLCD memory. Use the functions
Spi_Glcd_Set_Side, Spi_Glcd_Set_X, and Spi_Glcd_Set_Page to specify an
exact position on GLCD. Then, you can use Spi_Glcd_Write_Data or
Spi_Glcd_Read_Data on that location.
Requires
Reads data from from the current location of GLCD memory.
Example
tmp = Spi_Glcd_Read_Data;
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Spi_Glcd_Write_Data
Prototype
void Spi_Glcd_Write_Data(char data);
Description
Writes data to the current location in GLCD memory and moves to the next location.
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_Write_Data(data)
Spi_Glcd_Fill
Prototype
void Spi_Glcd_Fill(char pattern);
Description
Fills the GLCD memory with byte pattern. To clear the GLCD screen, use
Spi_Glcd_Fill(0); to fill the screen completely, use Spi_Glcd_Fill($FF).
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_Fill(0);
// Clear screen
Spi_Glcd_Dot
Prototype
void Spi_Glcd_Dot(char x_pos, char y_pos, char color);
Description
Draws a dot on the GLCD at coordinates (x, y). Parameter color determines the dot
state: 0 clears dot, 1 puts a dot, and 2 inverts dot state.
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_Dot(0, 0, 2); // Invert the dot in the upper left corner
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Spi_Glcd_Line
Prototype
void SPI_Glcd_Line(int x_start, int y_start, int x_end, int
y_end, char color);
Description
Draws a line on the GLCD from (x1, y1) to (x2, y2). Parameter color determines
the dot state: 0 draws an empty line (clear dots), 1 draws a full line (put dots), and 2
draws a “smart” line (invert each dot).
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_Line(0, 63, 50, 0, 2);
Spi_Glcd_V_Line
Prototype
void Spi_Glcd_V_Line(char y_start, char y_end, char x_pos, char
color);
Description
Draws a vertical line on the GLCD from (x, y1) to (x, y2). Parameter color determines
the dot state: 0 draws an empty line (clear dots), 1 draws a solid line (put dots), and 2
draws a “smart” line (invert each dot).
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_V_Line(0, 63, 0, 1);
Spi_Glcd_H_Line
Prototype
void Spi_Glcd_H_Line(char x_start, char x_end, char y_pos, char
color);
Description
Draws a horizontal line on the GLCD from (x1, y) to (x2, y). Parameter color determines the dot state: 0 draws an empty line (clear dots), 1 draws a solid line (put dots),
and 2 draws a “smart” line (invert each dot).
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_H_Line(0, 127, 0, 1);
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Spi_Glcd_Rectangle
Prototype
void Spi_Glcd_Rectangle(char x_upper_left, char y_upper_left,
char x_bottom_right, char y_bottom_right, char color);
Description
Draws a rectangle on the GLCD. Parameters (x1, y1) set the upper left corner,
(x2, y2) set the bottom right corner. Parameter color defines the border: 0 draws an
empty border (clear dots), 1 draws a solid border (put dots), and 2 draws a “smart” border (invert each dot).
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_Rectangle(10, 0, 30, 35, 1);
Spi_Glcd_Box
Prototype
void Spi_Glcd_Box(char x_upper_left, char y_upper_left, char
x_bottom_right, char y_bottom_right, char color);
Description
Draws a box on the GLCD. Parameters (x1, y1) set the upper left corner, (x2, y2)
set the bottom right corner. Parameter color defines the fill: 0 draws a white box (clear
dots), 1 draws a full box (put dots), and 2 draws an inverted box (invert each dot).
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_Box(10, 0, 30, 35, 1);
Spi_Glcd_Circle
Prototype
void Spi_Glcd_Circle(int x_center, int y_center, int radius, char
color);
Description
Draws a circle on the GLCD, centered at (x, y) with radius. Parameter color defines the
circle line: 0 draws an empty line (clear dots), 1 draws a solid line (put dots), and 2
draws a “smart” line (invert each dot).
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_Circle(63, 31, 25, 1);
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Spi_Glcd_Set_Font
Prototype
void SPI_Glcd_Set_Font(const char * activeFont, char aFontWidth,
char aFontHeight, unsigned int aFontOffs);
Description
Sets the font for text display routines, Spi_Glcd_Write_Char and
Spi_Glcd_Write_Text. Font needs to be formatted as an array of byte. Parameter
font_address specifies the address of the font; you can pass a font name with the @
operator. Parameters font_width and font_height specify the width and height of
characters in dots. Font width should not exceed 128 dots, and font height should not
exceed 8 dots. Parameter font_offset determines the ASCII character from which the
supplied font starts. Demo fonts supplied with the library have an offset of 32, which
means that they start with space.
If no font is specified, Spi_Glcd_Write_Char and Spi_Glcd_Write_Text will use
the default 5x8 font supplied with the library. You can create your own fonts by following the guidelines given in the file “GLCD_Fonts.dpas”. This file contains the default
fonts for GLCD, and is located in your installation folder, “Extra Examples” > “GLCD”.
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
// Use the custom 5x7 font "myfont" which starts with space (32):
Spi_Glcd_Set_Font(@myfont, 5, 7, 32);
Spi_Glcd_Write_Char
Prototype
void SPI_Glcd_Write_Char(char chr1, char x_pos, char page_num,
char color);
Description
Prints character at page (one of 8 GLCD lines, 0..7), x dots away from the left border of
display. Parameter color defines the “fill”: 0 writes a “white” letter (clear dots), 1 writes
a solid letter (put dots), and 2 writes a “smart” letter (invert each dot).
Use routine Spi_Glcd_Set_Font to specify font, or the default 5x7 font (included
with the library) will be used.
Requires
GLCD needs to be initialized, see Spi_Glcd_Init. Use the Spi_Glcd_Set_Font to
specify the font for display; if no font is specified, the default 5x8 font supplied with the
library will be used.
Example
Spi_Glcd_Write_Char('C', 0, 0, 1);
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Spi_Glcd_Write_Text
Prototype
void SPI_Glcd_Write_Text(char text[], char x_pos, char page_num,
char color);
Description
Prints text at page (one of 8 GLCD lines, 0..7), x dots away from the left border of
display. Parameter color defines the “fill”: 0 prints a “white” letters (clear dots), 1
prints solid letters (put dots), and 2 prints “smart” letters (invert each dot).
Use routine Spi_Glcd_Set_Font to specify font, or the default 5x7 font (included
with the library) will be used.
Requires
GLCD needs to be initialized, see Spi_Glcd_Init. Use the Spi_Glcd_Set_Font to
specify the font for display; if no font is specified, the default 5x8 font supplied with the
library will be used.
Example
Spi_Glcd_Write_Text('Hello world!', 0, 0, 1);
Spi_Glcd_Image
Prototype
void Spi_Glcd_Image(const char * image);
Description
Displays bitmap image on the GLCD. Parameter image should be formatted as an array
of 1024 bytes. Use the mikroPascal’s integrated Bitmap-to-LCD editor (menu option
Tools > Graphic LCD Editor) to convert image to a constant array suitable for display
on GLCD.
Requires
GLCD needs to be initialized. See Spi_Glcd_Init.
Example
Spi_Glcd_Image(my_image);
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Library Example
The example demonstrates how to communicate to KS0108 GLCD via SPI module, using serial to
parallel convertor MCP23S17.
extern const unsigned short
truck_bmp[];
char ii;
unsigned int jj;
char *someText;
void delay2S() {
Delay_ms(2000);
}
void main() {
ADCON1 |= 0x0F;
Spi_Init();
// Initialize SPI module
Spi_Glcd_Init(0,&PORTC, 0, &PORTC, 1);
Spi_Glcd_Fill(0xAA);
delay2S();
while(1) {
Spi_Glcd_Fill(0x00);
Spi_Glcd_Image( truck_bmp );
delay2S();
for(jj = 1; jj <= 40; jj++)
Spi_Glcd_Dot(jj,jj,1);
delay2S();
Spi_Glcd_Fill(0x00);
Spi_Glcd_Line(120, 1, 5,60, 1);
delay2S();
Spi_Glcd_Line(12, 42, 5,60, 1);
delay2S();
Spi_Glcd_Rectangle(12, 20, 93,57, 1);
delay2S();
//continues..
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//continues..
Spi_Glcd_Line(120, 12, 12,60, 1);
delay2S();
Spi_Glcd_H_Line(5, 40, 6, 1);
delay2S();
Spi_Glcd_Line(0, 12, 120, 60, 1);
Spi_Glcd_V_Line(7, 63, 127, 1);
delay2S();
for(ii = 1; ii <= 10; ii++)
Spi_Glcd_Circle(63, 32, 3*ii, 1);
delay2S();
Spi_Glcd_Box(12, 20, 70, 57, 2);
delay2S();
Spi_Glcd_Fill(0x00);
Spi_Glcd_Set_Font(&System3x6, 3, 6, 32);
someText = "SMALL FONT: 3X6";
Spi_Glcd_Write_Text(someText, 20, 5, 1);
Spi_Glcd_Set_Font(&FontSystem5x8, 5, 8, 32);
someText = "Large Font 5x8";
Spi_Glcd_Write_Text(someText, 3, 4, 1);
delay2S();
}
}
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Hardware Connection
1
D1
2
D2
3
D3
4
D4
5
D5
6
D6
7
D7
8
9
10
RC1 11
RC3 12
RC5 13
RC4 14
GPB0
GPA7
GPB1
GPA6
GPB2
GPA5
GPB3
GPA4
GPB4
GPA3
GPB5
GPA2
GPB6
GPA1
GPB7
GPA0
VDD
INTA
VSS
INTB
28
27
26
RST
25
E
24
RW
23
RS
22
CS2
21
CS1
VCC
20
11
19
RESET
CS
SCK
A2
SI
A1
SO
A0
18
12
RC0
13
17
14
16
15
8 Mhz
15
16
18
VCC
GND
OSC1
OSC2
RC0
RC1
PIC18F452
VCC
MCP23S17
D0
RC5
RC3
RC4
24
23
Vee
P1
5K
Contrast
Adjustment
VCC
Vo
1
CS1
CS2
GND
VCC
Vo
RS
R/W
E
D0
D1
D2
D3
D4
D5
D6
D7
RST
Vee
LED+
LED-
VCC
20
mikroElektronika
EasyPIC3
Development system
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Port Expander Library
The SPI Expander Library facilitates working with MCP23S17, Microchip’s SPI
port expander. The chip connects to the PIC according to the scheme presented
below.
Note: PIC need to have a hardware SPI module.
Note: SPI_Init() must be called before initializing Port Expander
Library Routines
Expander_Init
PortExpanderSelect
PortExpanderUnSelect
Expander_Read_Byte
Expander_Write_Byte
Expander_Set_Mode
Expander_Read_Array
Expander_Write_Array
Expander_Read_PortA
Expander_Read_PortB
Expander_Read_ArrayPortA
Expander_Read_ArrayPortB
Expander_Write_PortA
Expander_Write_PortB
Expander_Set_DirectionPortA
Expander_Set_DirectionPortB
Expander_Set_PullUpsPortA
Expander_Set_PullUpsPortB
Expander_Init
Prototype
void Expander_Init(char ModuleAddress, unsigned int * rstport,
unsigned int rstpin, unsigned int * csport, unsigned int cspin);
Description
Establishes SPI communication with the expander and initializes the expander. RstPort
and RstPin - Sets pin connected on reset pin of spi expander. CSPort and CSPin - Sets
pin connected on CS pin of spi expander. moduleaddress - address of spi expander
(hardware setting of A0, A1 and A2 pins (connected on VCC or GND) on spi expander).
Requires
This procedure needs to be called before using other routines of PORT Expander library.
SPI_Init() must be called before initializing Port Expander.
Example
Expander_Init(0, &PORTC, 0, &PORTC, 1);
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PortExpanderSelect
Prototype
void PortExpanderSelect;
Description
Selects current port expander.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
PortExpanderSelect;
PortExpanderUnSelect
Prototype
void PortExpanderUnSelect;
Description
Un-Selects current port expader.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
PortExpanderUnSelect;
Expander_Read_Byte
Prototype
char Expander_Read_Byte(char ModuleAddress, char RegAddress);
Returns
Byte read from port expander.
Description
Function reads byte from port expander on ModuleAddress and port on RegAddress.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Read_Byte(0,1);
Expander_Write_Byte
Prototype
void Expander_Write_Byte(char ModuleAddress,char RegAddress, char
Data);
Returns
Nothing.
Description
This routine writes data to port expander on ModuleAddress and port on
RegAddress.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Write_Byte(0,1,$FF);
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Expander_Set_Mode
Prototype
void Expander_Set_Mode(char ModuleAddress, char Mode);
Returns
Nothing.
Description
Sets port expander mode on ModuleAddress.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Set_Mode(1,0);
Expander_Read_ArrayPortA
Prototype
void Expander_Read_ArrayPortA(char ModuleAddress, char NoBytes,
char DestArray[]);
Returns
Nothing.
Description
This routine reads array of bytes (DestArray) from port expander on ModuleAddress
and portA. NoBytes represents number of read bytes.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Read_PortA(0,1,data);
Expander_Read_Array
Prototype
void Expander_Read_Array(char ModuleAddress, char StartAddress,
char NoBytes, char *DestArray);
Returns
Nothing.
Description
This routine reads array of bytes (DestArray) from port expander on ModuleAddress
and StartAddress. NoBytes represents number of read bytes.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Read_Array(1,1,5,data);
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Expander_Write_Array
Prototype
void Expander_Write_Array(char ModuleAddress, char StartAddress,
char NoBytes, char *SourceArray);
Returns
Nothing.
Description
This routine writes array of bytes (DestArray) to port expander on ModuleAddress
and StartAddress. NoBytes represents number of read bytes.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Write_Array(1,1,5,data);
Expander_Read_PortA
Prototype
char Expander_Read_PortA(char Address);
Returns
Read byte.
Description
This routine reads byte from port expander on Address and PortA.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Read_PortA(1);
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Expander_Read_ArrayPortB
Prototype
void Expander_Read_ArrayPortB(char ModuleAddress, char NoBytes,
char DestArray[]);
Returns
Nothing.
Description
This routine reads array of bytes (DestArray) from port expander on ModuleAddress
and portB. NoBytes represents number of read bytes.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Read_PortB(0,8,data);
Expander_Write_PortA
Prototype
void Expander_Write_PortA(char ModuleAddress, char Data);
Returns
Nothing.
Description
This routine writes byte to port expander on ModuleAddress and portA.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_write_PortA(3,$FF);
Expander_Write_PortB
Prototype
void Expander_Write_PortB(char ModuleAddress, char Data);
Returns
Nothing.
Description
This routine writes byte to port expander on ModuleAddress and portB.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_write_PortB(2,$FF);
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Expander_Set_DirectionPortA
Prototype
void Expander_Set_DirectionPortA(char ModuleAddress, char Data);
Description
Set port expander PortA pin as input or output.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Set_DirectionPortA(0,$FF);
Expander_Set_DirectionPortB
Prototype
void Expander_Set_DirectionPortB(char ModuleAddress, char Data);
Description
Set port expander PortB pin as input or output.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Set_DirectionPortB(0,$FF);
Expander_Set_PullUpsPortA
Prototype
void Expander_Set_PullUpsPortA(char ModuleAddress, char Data);
Description
This routine sets port expander PortA pin as pullup or pulldown.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Set_PullUpsPortA(0,$FF);
Expander_Set_PullUpsPortB
Prototype
void Expander_Set_PullUpsPortB(char ModuleAddress, char Data);
Description
This routine sets port expander PortB pin as pullup or pulldown.
Requires
PORT Expander must be initialized. See Expander_Init.
Example
Expander_Set_PullUpsPortB(0,$FF);
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Library Example
The example demonstrates how to communicate to port expander MCP23S17.
unsigned char
i;
void main(){
ADCON1 |= 0x0f;
TRISB = 0x00;
LATB = 0xFF;
Delay_ms(2000);
Spi_Init();
// Initialize SPI module
Expander_Init(0, &PORTC, 0, &PORTC, 1);
Expander_Set_DirectionPortA(0, 0);
// initialize port expander
// set expander's porta to be output
Expander_Set_DirectionPortB(0,0xFF);
// set expander's porta to be input
Expander_Set_PullUpsPortB(0,0xFF);
// set pull ups to all of the expander's portb pins
i = 0;
while(1) {
Expander_Write_PortA(0, i++);
// write i to expander's porta
LATB = Expander_Read_PortB(0);
// read expander's portb and write it to PIC's LATB
Delay_ms(20);
}
}
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Hardware Connection
MCP23S17
1
2
3
4
GPA7
GPB1
GPA6
GPB2
GPA5
GPB3
GPA4
GPB4
GPA3
GPB5
GPA2
GPB6
GPA1
GPB7
GPA0
5
6
7
VCC
8
9
10
RC1 11
RC3 12
RC5 13
RC4 14
28
27
26
25
24
23
22
VDD
INTA
VSS
INTB
VCC
21
20
11
19
CS
RESET
SCK
A2
SI
A1
SO
A0
12
18 RC0
13
17
14
15
16
16
8 Mhz
15
18
1
3
5
1
3
5
7
2
4
6
8
7
2
4
6
8
9
10
9
10
VCC
PORTB
VCC
VCC
GND
OSC1
OSC2
RC0
RC1
PIC18F452
GPB0
RC5
RC3
RC4
24
23
PORTA
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