Matrix Orbital LK204-25-WB (75-529-46)

Matrix Orbital LK204-25-WB (75-529-46)
LK204-25
Technical Manual
Revision: 1.0
Contents
Contents
ii
1 Introduction
1.1 What to Expect From the LK204-25 . .
1.2 What Not to Expect From the LK204-25
1.3 Keypad Interface . . . . . . . . . . . .
1.4 Setup for Testing . . . . . . . . . . . .
1.5 Trying Out the LK204-25 . . . . . . . .
1.6 Trying out a Keypad . . . . . . . . . .
1.6.1 Here’s what to Do . . . . . . .
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2 Connections
2.1 Connector Pinout . . . . . . . . . . .
2.1.1 Power and I2 C Connections .
2.1.2 Five Volt Modules . . . . . .
2.1.3 Wide Voltage Range Modules
2.1.4 RS-232 Communications . . .
2.1.5 Configuring RS-232 and I2 C .
2.1.6 I2 C Communications . . . . .
2.1.7 ACK . . . . . . . . . . . . .
2.2 General Purpose Outputs . . . . . . .
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4
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3 Displaying Text
3.1 General . . . . . . . . . . . . . . . . . . . . . . .
3.2 The built in Character Font . . . . . . . . . . . . .
3.3 Writing Text to the Display . . . . . . . . . . . . .
3.4 Text Commands . . . . . . . . . . . . . . . . . . .
3.4.1 Auto line wrap on (254 67) . . . . . . . .
3.4.2 Auto line wrap off (254 68) . . . . . . . .
3.4.3 Auto scroll on (254 81) . . . . . . . . . .
3.4.4 Auto scroll off (254 82) . . . . . . . . . .
3.4.5 Set cursor position (254 71 [column] [row])
3.4.6 Send cursor home (254 72) . . . . . . . . .
3.4.7 Turn on underline cursor (254 74) . . . . .
3.4.8 Turn off underline cursor (254 75) . . . . .
3.4.9 Turn on block (blinking) cursor (254 83) .
3.4.10 Turn off block (blinking) cursor (254 84) .
3.4.11 Cursor left (254 76) . . . . . . . . . . . . .
3.4.12 Cursor right (254 77) . . . . . . . . . . . .
Matrix Orbital
LK204-25
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1
1
1
1
2
2
3
3
ii
4 Keypad Interface
4.1 General . . . . . . . . . . . . . . . . . . . . .
4.2 Connections . . . . . . . . . . . . . . . . . . .
4.3 I2 C Interface . . . . . . . . . . . . . . . . . .
4.4 RS-232 Interface . . . . . . . . . . . . . . . .
4.5 Keypad Commands . . . . . . . . . . . . . . .
4.5.1 Auto repeat mode on (254 126 [mode])
4.5.2 Auto repeat mode off (254 96) . . . . .
4.5.3 Auto transmit keypresses on (254 65) .
4.5.4 Auto transmit keypresses off (254 79) .
4.5.5 Clear key buffer (254 69) . . . . . . . .
4.5.6 Poll keypad (254 38) . . . . . . . . . .
4.5.7 Set debounce time (254 85 [time]) . . .
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15
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18
18
5 Bar Graphs and Special Characters
5.1 Command List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1.1 Initialize wide vertical bar graph (254 118) . . . . . . . . . . . .
5.1.2 Initialize narrow vertical bar graph (154 115) . . . . . . . . . . .
5.1.3 Draw vertical bar graph (254 61 [column] [height]) . . . . . . . .
5.1.4 Initialize horizontal bar graph (254 104) . . . . . . . . . . . . . .
5.1.5 Draw horizontal bar graph (254 124 [column] [row] [dir] [length])
5.1.6 Define custom character (254 78 [c] [8 bytes]) . . . . . . . . . .
5.1.7 Initialize large digits (254 110) . . . . . . . . . . . . . . . . . . .
5.1.8 Place large digit 254 35 [col] [digit] . . . . . . . . . . . . . . . .
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18
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6 Miscellaneous Commands
6.1 Command List . . . . . . . . . . . . . . . . . . .
6.1.1 Clear display (254 88) . . . . . . . . . . .
6.1.2 Set Contrast (254 80 [contrast]) . . . . . .
6.1.3 Backlight on (254 66[minutes]) . . . . . .
6.1.4 Backlight off (254 70) . . . . . . . . . . .
6.1.5 General purpose output off (254 86 [gpo #])
6.1.6 General purpose output on (254 87 [gpo #])
6.1.7 Read module type (254 55) . . . . . . . . .
6.1.8 Read Serial Number (254 53) . . . . . . .
6.1.9 Read Version Number (254 54) . . . . . .
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21
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23
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7 Appendix: Command Summary
7.1 General . . . . . . . . . . . . . .
7.2 Issuing Commands . . . . . . . .
7.3 On Numbers . . . . . . . . . . . .
7.3.1 ASCII Characters . . . . .
7.4 Text Commands . . . . . . . . . .
7.5 Keypad Interface Commands . . .
7.6 Bar Graphs and Special Characters
7.7 Miscellaneous Commands . . . .
Matrix Orbital
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LK204-25
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iii
8 Appendix: Specifications and Options
30
8.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8.2 Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
9 Appendix: Glossary
Matrix Orbital
32
LK204-25
iv
1
Introduction
The LK204-25 comes equipped with the following features;
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20 column by 4 line text display
Built in font with provision for up to 8 user defined characters
Speeds from 1200 bps to a lighting fast 19.2 Kbps over RS-232
Communication over I2 C or RS-232
Use of up to 16 modules on the same 2-wire I2 C interface
Fully buffered so that no delays in transmission are ever necessary
Software controlled contrast
Backlight with configurable time out setting up to 180 minutes
Use of up to a 25 key keypad with a 10 key buffer
Six general purpose outputs for a variety of applications
Horizontal or vertical bar graphs
Variable power options, +5V or +9V to +15V
Extended temperature option
Fits Matrix Orbital’s dual PC Bay inserts without any modifications
Built in large digits
1.1 What to Expect From the LK204-25
The LK204-25 is designed as the display unit for an associated controller. The controller may be anything
from a single board, special purpose micro-controller to a PC, depending on the application. This controller
is responsible for what is displayed on the screen of the display.
The display provides a simple command structure to allow text and bar graphs to be displayed on the
screen. Text fonts are built in, and use standard ASCII mapping. Provision is made for up to 8 user defined
characters.
The screen is luminous for low light situations. The display may be turned on or off under program
control. Brightness is adjustable to compensate for differing lighting conditions.
General purpose outputs allow the controller to switch up to six electronic or electro-mechanical devices
by issuing commands to the display unit. These can be used for controlling LEDs, relays, etc.
1.2 What Not to Expect From the LK204-25
The display does not include bitmap graphics capability, except that permitted by defining special characters.
1.3 Keypad Interface
The keypad interface takes row / column input and converts it to ASCII characters, which are delivered
out the RS-232 or I2 C port to the associated controller. Note that the keypad is not used to directly control
any aspect of the operation of the display, which acts simply as a matrix to serial converter. To use the
keypad to control the display, the controller must be programmed accordingly.
Matrix Orbital
LK204-25
1
1.4 Setup for Testing
Before setting up the application the user may want to try out the display. This is easily done with a PC.
If not equipped with a dual bay PC mounting kit, the following will be required;
• A 4-pin power connector of the type used to connect 3.5" floppy drive. Take care not to connect the
display to an unmodified spare power connector in a PC.
• A 5V power supply.
• A PC with a spare RS-232 port (COM1 or COM2).
• A 9 or 25 pin RS-232 serial cable. If using a 25 conductor cable, a 9 to 25 pin adapter will be required.
Figure 1: Connections for Testing
1. Refer to the Figure above for the following steps.
2. Wire the connector to the power supply. On most connectors the RED lead will go to +5V and the
BLACK lead to GND.
NOTE The Manufacturer’s Warranty becomes void if the unit is subjected to over-voltage
or reversed polarity.
3. Connect the display to the PC using the serial cable and adapter if required. Make sure the RS-232
cable includes the required ground lead. There must be no voltage differential between the RS-232
ground and the power supply ground.
4. Connect the power connector, making sure that the +5V goes to V+. Turn on the power; the display
should come on.
1.5 Trying Out the LK204-25
The unit should be connected to power. The PC and display should be on. To experiment with typing
text, run a PC terminal program, such as Hyperterm. Make sure it’s configured to use the correct port. Set
Matrix Orbital
LK204-25
2
the baud rate to 19,200. If characters are typed on the keyboard, they should now appear on the display
screen. Text will wrap around to the next line when the end of a line has been reached.
A few common ASCII control characters work as follows;
Table 1: Common ASCII Control Characters
Character
CR
Hex Value
0x0D
LF
0x0A
FF
0x0C
BS
0x08
Function
Moves cursor to beginning of the
current line.
Moves cursor to beginning of the
next ( or previous ) line.
Clears the display and puts the cursor at the top left.
Moves the cursor one position to the
left and clears that position.
NOTE These command characters are not guaranteed to work on other Matrix Orbital
display modules.
To exercise some of the other features of the display, a program (in any convenient language such as Basic
or C) will need to be written in order to issue the required command strings. Most terminal programs are
unable to issue the 0xFE character needed as a command prefix.
1.6 Trying out a Keypad
Since a number of different keypad types can be connected to the display, the results may be a little
unpredictable. At this point all we need to do is make sure that the keypad and interface work, and possibly
generate an ASCII map for any programming needs. The keypad interface on the display converts a row /
column connection to an ASCII character. By default, a keypress is transmitted as serial data immediately.
Keypad buffering can be selected using the appropriate commands.
1.6.1
Here’s what to Do
1. The PC should be running a terminal program, such as Hyperterm.
2. With the display connected to the PC, plug in the keypad. If the connector has fewer pins than the one
on the display, center it as well as possible.
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3
NOTES
• The keypad connector must be wired with columns on one side and rows on the other
side of the center of the connector. If the keypad isn’t wired this way an adapter must
be made or the connector must be rewired to meet this requirement.
• The connector is reversible. Reversing the connector will not damage the keypad or
the display, but will however, change the ASCII character map.
3. Press a key on the keypad. An upper case ASCII character (A-Y) should appear on the PC screen.
Different keys should generate different characters.
To experiment, reverse the connector and see if it generates a more logical set of characters. Ultimately, the
program in the micro-controller will have to ’map’ these characters to the ones marked on the keypad, which
will likely be different.
2
Connections
2.1 Connector Pinout
Refer to the Figure below for this chapter.
Figure 2: Electrical Connections
The display has four connectors;
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Table 2: Connectors and Functions
Connector
14 pin dual header
4 pin
10 pin header
DB-9F
2.1.1
Function
General purpose outputs (6)
Power (5.0 VDC) and I2 C communications
Keypad
RS-232 / power
Power and I2 C Connections
Power is applied via pins 1 and 4 as shown in the Figure above. Power requirement is +5 VDC ±0.25V.
Power may also be supplied via the RS-232 connector as described in the next section.
WARNINGS
• Do not apply any power with reversed polarization.
• Do not apply any voltage other than the specified voltage.
• Do not use any cables other than the cables supplied by Matrix
Orbital, unless aware of the modifications required.
• Do not apply voltage to the DB-9 connector AND power connector.
• Do not apply more than +5Vdc to pin #9 on the DB-9 connector
Connector pinout is as follows;
Figure 3: Power Connector
Table 3: Power Connector
Pin 4
Pin 3
Pin 2
Pin 1
Matrix Orbital
Ground
SDA (I2 C data)
SCL (I2 C clock)
+5.0 VDC (+7 to +15 VDC with wide voltage option)
LK204-25
5
2.1.2
Five Volt Modules
If the display is used in a PC it is tempting to plug a spare power connector into the unit. Don’t do this!
Wiring for the PC power connector and that required for the display are different, as shown in the Figure
below.
Figure 4: Wiring for Five Volt Modules
Matrix Orbital can supply an adapter cable designed to use with the display when it’s installed in a PC.
The cable is wired as shown in Figure the below.
NOTE This connector does not provide connections for I2 C.
Figure 5: Five Volt Power Cable
2.1.3
Wide Voltage Range Modules
NOTE Do not use this cable unless the display module has the "Wide voltage range"
option (option V). Use of the 12 volt power cable with 5 volt modules will damage the
module.
The 12 volt power cable is designed for use with wide voltage range display modules mounted in a PC.
Wiring required for the 12 volt power connector is shown in the Figure below.
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6
Figure 6: Wiring for Twelve Volt Modules
Matrix Orbital can supply an adapter cable designed to use with the display module when it’s installed
in a PC. The cable is wired as shown in the Figure below.
Figure 7: Twelve Volt Power Cable
2.1.4
RS-232 Communications
A standard DB-9F is provided for RS-232 communications. Power may also be supplied via this connector if desired. See the Figure below for pin connections.
Figure 8: RS-232 and Power Connector
The RS-232 connector on the PC cable is wired so that a standard ’straight through’ 9 pin D-sub cable
may be used to connect the module to a standard serial port such as COM ports on PCs. Note that this device
Matrix Orbital
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7
complies with the EIA232 standard in that it uses signal levels from +/- 3V to +/- 12V. It will not operate
correctly at TTL (0 to +5V) levels.
Table 4: RS-232 Pinout
Pin Number
2
3
5
Direction
Data from LCD
Data to LCD
-
Description
Data out (LCD)
Data in (LCD)
Ground
LCD
Tx
Rx
gnd
Host
Rx
Tx
gnd
The power connector on the PC cable is wired as shown in the Figure above.
2.1.5
Configuring RS-232 and I2 C
RS-232 baud rate and I2 C address are configured by means of jumpers.
Figure 9: RS-232 Jumpers
The module is supplied with jumpers J1 and J2 installed, which gives an RS-232 baud rate of 19200 and
an I2 C address of 0x5C.
• RS-232 port: J0, J1, J2 - control baud rate. RS-232 format is 8N1 (8 bits, no parity, one stop bit)
• I2 C port: J0, J1, J2, J3 - sets slave peripheral address
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8
Table 5: Serial Baud Rates
Baud Rate
1200
2400
9600
19200
1200
2400
9600
19200
2.1.6
Slave Address
50H
52H
54H
56H
58H
5AH
5CH
5EH
60H
62H
64H
66H
68H
6AH
6CH
6EH
J3
out
out
out
out
out
out
out
out
in
in
in
in
in
in
in
in
J2
out
out
out
out
in
in
in
in
out
out
out
out
in
in
in
in
J1
out
out
in
in
out
out
in
in
out
out
in
in
out
out
in
in
J0
out
in
out
in
out
in
out
in
out
in
out
in
out
in
out
in
I2 C Communications
I2 C communications runs at 100 Kbps and supports up to 127 units on a single communications line.
The I2 C data line operates on 5 volt CMOS levels.
2.1.7
ACK
The idea of ACK is to indicate when the data has been received correctly. ACK does not indicate data
incorrectly received. ACK simply fails to indicate when data is correctly received. Clearly, this is of limited
usefulness and even less so with Matrix Orbital modules. Matrix Orbital modules are not capable of failing
to acknowledge an incorrectly received byte in response to that bytes transition. They are only capable of
failing to acknowledge the bytes following the byte, which was not received. To fully understand the reasons
for this one needs to understand something about how a Matrix Orbital module processes data. Basically the
reason why a Matrix Orbital module might fail to receive a byte correctly is that it was unable to process the
byte previous before the failed byte was transmitted. Because the module cannot possibly know that it would
be unable to store the byte before the next byte was received it cannot know to not ACK. The reason for this
situation in deference to situations one might be familiar with (i.e., memory chips, etc) is that the Matrix
Orbital module employs a micro-processor to perform these data storage functions. A memory chip takes
care of these things entirely within hardware subsystems that operate at the same speed as the transmission
themselves.
The display uses a standard Phillips 7bit address as defined by Phillips. However, Matrix Orbital specifies
I2 C address in 8bits. The 8th bit, least significant bit (LSB or Low Order Bit) of the 8bit address is read
Matrix Orbital
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9
/ write bit. If we take a standard Phillips 7bit address of 45hex this would be in binary 1000101. This is
7bits. Matrix Orbital would describe the Phillips I2 C address of 45hex as 8Ahex. The read address would
be 8Bhex.
For more information on Phillips I2 C please visit;
!"#%$!&%'()*
2.2 General Purpose Outputs
The display has six general purpose outputs. These are provided to control relays or other electronic devices. This allows external devices to be turned on or off using the PC or controller and software commands.
Each output is wired as shown in the Figure below. The + terminal is connected directly to the module
positive supply, the - terminal is connected through a 240 ohm current limiting resistor and the electronic
switch to ground.
Figure 10: General Purpose Outputs
Maximum allowable current is 20 mA, which is enforced by the current limiting resistor. If the device
being switched has a resistance of 240 ohms or more the corresponding resistor may be shorted. Solder a
small jumper wire (wirewrap wire is good) from the feedthrough hole to the corresponding negative pin for
the GPO in question.
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Figure 11: Bypassing 240 ohm Resistor
NOTE The GPOs do not have any over current or over / under voltage protection so
care must be taken when using them. For instance, if the external device is a relay it must
be fully clamped using a diode and capacitor to absorb any generated back electro-motive
force (EMF).
Figure 12: Clamping a Relay
3
Displaying Text
This chapter describes the various text-display commands in detail. Before issuing commands to the
LK204-25 please read sections 7.2 and 7.3.
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3.1 General
Text is displayed on the LK204-25 using the built in 5x7 dot matrix font, in addition to up to 8 user
defined characters.
3.2 The built in Character Font
The display includes a built in 5x7 dot matrix font with the full range of ASCII characters plus a variety
of extended characters as shown in the Figure below.
Figure 13: Character Set
In addition to the built in characters, users may define up to 8 special characters which, once defined,
occupy positions 0x00 to 0x07 in the above chart. The display does not have provision to download other
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fonts.
3.3 Writing Text to the Display
When the display receives a character, it displays that character at the position currently defined. The
next character sent to the module then advances to the following position on the display. Characters are
drawn using the built in font, and only characters defined in the font are actually displayed. Characters
that are not defined by the built in font print as a space (i.e., the cursor is advanced for the next character).
The position where text is to be inserted is a character location stored in the display’s volatile memory and
maintained internally by the display’s firmware. This position is manipulated by the commands shown in
the following section.
3.4 Text Commands
In this section commands are identified by their names and decimal values. Hex and ASCII equivalents
are given in the summary.
3.4.1
Auto line wrap on (254 67)
Enables automatic line wrapping. Note that this is not ’word wrapping’ and wraps may occur in the
middle of a word.
3.4.2
Auto line wrap off (254 68)
Disables automatic line wrapping. Characters beyond the end of a line will be lost.
3.4.3
Auto scroll on (254 81)
When auto scrolling is on, it causes the display to shift the entire display’s contents up to make room for
a new line of text when the text reaches the scroll position (the bottom right character position).
3.4.4
Auto scroll off (254 82)
When auto scrolling is disabled, text will wrap to the top left corner of the display area. Existing text in
the display area is not erased before new text is placed. A series of ’spaces’ followed by a “Cursor home”
command may be used to erase the top line of text.
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3.4.5
Set cursor position (254 71 [column] [row])
This command sets the cursor position (text insertion point) to the [column] and [row] specified. Columns
have values from 1 to 20 (0x01 to 0x14) and rows have values of 1 and 2 (0x01 and 0x02).
3.4.6
Send cursor home (254 72)
This command moves the cursor position (text insertion point) to the top left of the display area.
3.4.7
Turn on underline cursor (254 74)
Turns on the underline cursor. The cursor shows the current text insertion point. Both underline and
blinking cursors may be turned on or off independently. The cursor is off by default.
3.4.8
Turn off underline cursor (254 75)
Turns off the underline cursor. Does not affect the blinking block cursor.
3.4.9
Turn on block (blinking) cursor (254 83)
Turns on the blinking block cursor. The cursor shows the current text insertion point. Both blinking and
underline cursors may be turned on or off independently. The cursor is off by default
3.4.10
Turn off block (blinking) cursor (254 84)
Turns off the blinking block cursor. Does not affect the underline cursor.
3.4.11
Cursor left (254 76)
Moves the cursor one position to the left but does not erase any character that may be in that position.
Note that this command moves the text insertion point even if the cursor is turned off.
NOTE A ’destructive backspace’, which erases the character to the left of the original
position, may be done by issuing the following sequence: cursor left, space, cursor left.
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3.4.12
Cursor right (254 77)
Moves the cursor one position to the right but does not erase any character that may be in that position.
Note that this command moves the text insertion point even if the cursor is turned off.
4
Keypad Interface
This chapter describes the keypad interface and associated commands in detail.
4.1 General
The display keypad interface processes the keypad row / column matrix into a serial (RS-232 or I 2 C)
data byte stream. Aside from this processing, the keypad has no effect on the display. Keystrokes to the
display must be routed through the controller.
4.2 Connections
Figure 14: Keypad Connector
The connector is not ’keyed’ so the keypad will probably plug in either of two ways. The display will not
be damaged by reversing the connector, but the keypad will generate a different ASCII character mapping
for each position. If the connector has fewer than 10 pins it should be centered on the display connector.
The diagram shows the logical layout (row 1, column 1 in upper left). The connector for the keypad is a
10 pin 0.1" spacing male header. Pins 1 through 5 are columns and pins 6 through 10 are rows. The keypad
is scanned whenever a key is pressed: there is no continuous key scan. This means that key presses are dealt
with immediately without any appreciable latency. This also prevents electrical noise which is often caused
by continuous key scans.
NOTE The keypads may be laid out in a different pattern. If this is the case, the user will
need to interpret the key codes differently.
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Table 6: Keypad Layout
Rows
1
2
3
4
5
1
A
F
K
P
U
Columns
2
3
B C
G H
L M
Q R
V W
4
D
I
N
S
X
5
E
J
O
T
Y
NOTE The keypad connector must be wired with columns on one side and rows on the
other side of the center of the connector. In situations where the keypad isn’t wired this
way an adapter will need to be made, or the user should rewire the connector to meet this
requirement.
4.3 I2 C Interface
The keypad is read by I2 C master read. In short, this means that a read of the module will always return
the first unread key press. A read is initiated by writing to the module with its base address plus 1, then
clocking the module’s return byte after the module releases the SDA line. Much more detail on this basic
I2 C function can be found in the I2 C specification by Phillips. A good reference is also available at;
!"#%$!&%'()*
The module contains a ten key press buffer so that it can be polled for key presses at an infrequent rate
(every 500 to 1000 mS is typical). All returned key presses indicate the presence or absence of additional
logged key presses by the most significant bit (MSB - bit 7). If the user has pressed two keys since the last
poll of the keypad interface, the first read will return the key code with bit 7 set and the second read will
return the key code with bit 7 clear. The application must take into account this bit to keep up with user key
presses. If there are no keypresses detected, the module will return zero (0x00).
4.4 RS-232 Interface
By default on any press of a key, the module will immediately send out the key code at the selected baud
rate. This behavior can be modified using commands found in the next section.
4.5 Keypad Commands
4.5.1
Auto repeat mode on (254 126 [mode])
[mode] = 0x00 gives Resend Key Code mode
[mode] = 0x01 gives Key Down / Key Up Code mode
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16
Two Modes of auto repeat are available and are set via the same command.
1. Resend Key Code: This mode is similar to the action of a keyboard on a PC. In this mode, when a
key is held down, the key code is transmitted immediately followed by a 1/2 second delay. After this
delay, key codes will be sent via the RS-232 interface at a rate of about 5 codes per second. This mode
has no effect if polling or if using the I2 C interface.
2. Key Down / Key Up Codes: This mode may be used when the typematic parameters of the “Resend
key code” mode are unacceptable or if the unit is being operated in polled mode. The host system
detects the press of a key and simulates an auto repeat inside the host system until the key release is
detected.
In this mode, when a key is held down the key code is transmitted immediately and no other codes will be
sent until the key is released. On the release of the key, the key release code transmitted will be a value
equal to the “Key down code” plus 20 hex. For example, the key code associated with key ’P’ (0x50) is
pressed, the release code is ’p’ (0x70). In RS-232 polled mode or via the I 2 C interface, the “Key down /
key up” codes are used; however, the user should be careful of timing details. If the poll rate is slower than
the simulated auto - repeat it is possible that polling for a key up code will be delayed long enough for an
unwanted key repeat to be generated.
Figure 15: Poll Timing
4.5.2
Auto repeat mode off (254 96)
This command turns off auto repeat mode.
4.5.3
Auto transmit keypresses on (254 65)
In this mode, all keypresses are sent immediately to the host system without the use of the poll keypad
command. This is the default mode on power up.
4.5.4
Auto transmit keypresses off (254 79)
In this mode, up to 10 keypresses are buffered until the unit is polled by the host system via the poll
keypad command. Issuing this command places the unit in polled mode.
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4.5.5
Clear key buffer (254 69)
This command clears any unread keypresses. In a menuing application, if the user presses a key which
changes the menu context, any following key presses may be inaccurate and can be cleared out of the buffer
between menu changes to prevent jumping around the menu tree. It may also be used to, in effect, reset the
keypad in case the host application resets for whatever reason.
4.5.6
Poll keypad (254 38)
This command returns any unbuffered keypresses via the RS-232 interface. The host system must be
set up to receive the key codes. When the display receives this command it will immediately return any
unbuffered keypresses which may have not been read already. If there is more than one keypress buffered,
then the high order bit (MSB) of this returned keycode will be set (1). If this is the only buffered keypress,
then the MSB will be reset (0). If there are no buffered keypresses, then the returned code will be 0x00.
Please note to make use of this command the "Auto transmit keypress" mode should be off.
4.5.7
Set debounce time (254 85 [time])
[time] is in increments of 6.554 milliseconds.
This command sets the time between key press and key read. All key types with the exception of latched
piezo switches will ’bounce’ for a varying time, depending on their physical characteristics. The default
debounce time for the module is about 52 mS, which is adequate for most membrane keypads.
5
Bar Graphs and Special Characters
The display includes the ability to draw bar graphs (either horizontal or vertical) and allows users to
define up to eight special characters.
Eight characters (ASCII values 0x00 to 0x07) are set aside for use with bar graphs, user defined characters, and big numbers. Since the same 8 characters are used for each function, the functions may not be used
simultaneously. The characters may be defined or redefined at any time by issuing the commands shown
in this section. Once defined, they may be used either by means of the bar graph commands, or by simply
issuing one of the ASCII values 0x00 to 0x07 (which is not prefixed by the command byte, 254).
5.1 Command List
5.1.1
Initialize wide vertical bar graph (254 118)
This command defines the 8 special / user characters to be blocks suitable for use in drawing wide (5
pixel) vertical bar graphs. Any previously existing definitions will be lost. Once this command has been
issued, any number of vertical bar graphs may be drawn unless the characters are redefined by another
command.
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18
5.1.2
Initialize narrow vertical bar graph (154 115)
This command defines the 8 special / user characters to be blocks suitable for use in drawing narrow (2
pixel) vertical bar graphs. Any previously existing definitions will be lost. Once this command has been
issued, any number of vertical bar graphs may be drawn unless the characters are redefined by another
command
5.1.3
Draw vertical bar graph (254 61 [column] [height])
Draws a vertical bar graph in [column] having a height of [height] pixels. The height may range from
0 to 20 (0x00 to 0x14) pixels. The necessary characters must first be initialized by either of the commands
shown in section 5.1.1 or 5.1.2, which will determine the width of the graph drawn. Graph may be erased
by drawing a bar graph of height = 0 in the same column.
5.1.4
Initialize horizontal bar graph (254 104)
This command defines the 8 special / user characters to be blocks suitable for use in drawing horizontal
bar graphs. Any previously existing definitions will be lost. Once this command has been issued, any number
of horizontal bar graphs may be drawn unless the characters are redefined by another command.
5.1.5
Draw horizontal bar graph (254 124 [column] [row] [dir] [length])
Draws a horizontal bar graph in [row] starting at [column] with a length of [length] pixels. [row] may
have a value of 0x01 or 0x02, column may range from 0x01 to 0x14 and length may be from 0x00 to 0x64
(0 to 100) if the graph can extend the full width of the screen. Each column is 5 pixels wide (spaces between
the columns don’t count).
[dir] specifies the direction: 0x00 goes from left to right, 0x01 goes from right to left.
5.1.6
Define custom character (254 78 [c] [8 bytes])
The display allows up to 8 user defined (custom) characters. These characters occupy the first 8 (0x00
to 0x07) places in the character set.
Custom characters occupy a 5x8 pixel matrix. built in characters are 5x7: the bottom row of pixels is
normally reserved for the underline cursor. The underline cursor should be turned off if the bottom row of
pixels forms part of a custom character.
The characters are defined by issuing the command 254 78 [c] followed by 8 bytes to define the character.
[c] is the character number (0x00 to 0x07). The 8 bytes are mapped as shown below;
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19
Table 7: 8 Byte Map
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
1
6
11
16
21
26
31
36
MSB LSB
2
3
4
7
8
9
12 13 14
17 18 19
22 23 24
27 28 29
32 33 34
37 38 39
5
10
15
20
25
30
35
40
Data Byte 1
Data Byte 2
Data Byte 3
Data Byte 4
Data Byte 5
Data Byte 6
Data Byte 7
Data Byte 8
A "1" bit indicates an on (black) pixel, a "0" bit indicates an off (clear) pixel.
Once defined, a character is displayed simply by issuing a value (0x00 to 0x07) corresponding to the
character number. The character will be laid out as follows;
Table 8: Character Values
1
6
11
16
21
26
31
36
2
3
4
7
8
9
12 13 14
17 18 19
22 23 24
27 28 29
32 33 34
37 38 39
Cursor Line
5
10
15
20
25
30
35
40
NOTE Custom characters will be erased if any of the "Initialize bar graph" commands
are issued.
5.1.7
Initialize large digits (254 110)
This command defines the 8 special / user characters to be blocks suitable for use in drawing large digits.
Any previously existing definitions will be lost. Once this command has been issued, any number of large
characters may be placed until the characters are re-defined by another command.
Matrix Orbital
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5.1.8
Place large digit 254 35 [col] [digit]
This command allows the large digits to be drawn on the display screen. Numbers of almost full display
height may be placed along side regular text on four row displays. The column number has a maximum
value which is less than the display width because the digits are all three columns wide.
Before using this command, the “Initialize large digits” command must be issued to define the blocks
necessary to make up the digits. If regular text and large digits are mixed on one screen, the user should
always set the display cursor position before placing regular text because the creation of a large digit will
leave the cursor position to the bottom right of the large digit and not at the last regular text write position.
[col] can have values from 0x01 to 0x12 (1 to 18).
[digit] has values from 0x00 to 0x09 (0 to 9).
6
Miscellaneous Commands
The commands listed in this chapter don’t readily fit in any of the other categories, or are used in more
than one category.
6.1 Command List
6.1.1
Clear display (254 88)
This command clears the display and resets the text insertion point to the top left of the screen.
6.1.2
Set Contrast (254 80 [contrast])
This command sets the display’s contrast to [contrast], where [contrast] is a value between 0x00 and
0xFF (between 0 and 255). Lower values cause "on" elements in the display area to appear lighter, while
higher values cause "on" elements to appear darker. Lighting conditions will affect the actual value used
for optimal viewing. Individual display modules will also differ slightly from each other in appearance. In
addition, values for optimal viewing while the display backlight is on may differ from values used when
backlight is off.
6.1.3
Backlight on (254 66[minutes])
This command turns on the backlight for a time of [minutes] minutes. If [minutes] is zero (0), the
backlight will remain on indefinitely.
NOTE The factory default for backlight is on.
Matrix Orbital
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21
6.1.4
Backlight off (254 70)
This command turns the display off.
6.1.5
General purpose output off (254 86 [gpo #])
This command turns OFF any of the general purpose outputs. [gpo #] is 1 to 6. Note that OFF means
that the output floats.
6.1.6
General purpose output on (254 87 [gpo #])
This command turns ON any of the general purpose outputs. [gpo #] is 1 to 6. ON means that the output
is pulled low (ground via 240 ohms).
6.1.7
Read module type (254 55)
This command will return, over the RS-232 interface, the model type value of the module. Values for
various modules at the time of this publication are as follows;
Table 9: Module Values
LCD0821 - 0x01
LCD4021 - 0x06
LK204-25 - 0x09
VFD2041 - 0x0C
VK204-25 - 0x0F
GLK24064-25 - 0x15
LK402-12 - 0x33
6.1.8
LCD2021 - 0x03
LCD4041 - 0x07
LK404-55 - 0x0A
VFD4021 - 0x0D
GLC12232 - 0x10
GLK12232-25 - 0x22
LK162-12 - 0x34
LCD2041 - 0x05
LK202-25 - 0x08
VFD2021 - 0x0B
VK202-25 - 0x0E
GLC24064 - 0x13
LK404-AT - 0x31
LK204-25PC - 0x35
Read Serial Number (254 53)
This command will return, over the RS-232 interface, the serial number of the module as it was previously stored.
6.1.9
Read Version Number (254 54)
This command will return the firmware version number of the display.
Matrix Orbital
LK204-25
22
7
Appendix: Command Summary
7.1 General
The operation of the display is controlled by a simple and consistent command set.
Commands control;
• Text display
• Graphics display
• Keypad interface
• Miscellaneous operating parameters
This chapter includes summary tables of all commands.
7.2 Issuing Commands
Commands are issued to the display by the controller. In a test setup, commands can be issued to
the display by means of a BASIC program, using the chr$( ) function. In the tables below, we’ve shown
commands in hex, ASCII and decimal form. All commands begin with the prefix character 0xFE (254
decimal). These commands are issued on the serial communications link (I 2 C or RS-232) at the currently
defined baud rate.
For example (using BASIC in a test setup), the user could issue the command to clear the screen on the
display by including the line;
+,.-0/12.34!056879:.;=<4!5>[email protected]@;
In the BASIC program.
7.3 On Numbers
Like all computerized devices, the display operates with commands and values in the form of binary
numbers. These binary numbers are arranged in 8 digit (i.e. 8 bit) groups called bytes. The decimal value of
a byte may have any value from 0 to 255.
Bytes are usually specified in either decimal or hexadecimal (base 16) form for convenience, since binary
numbers are confusing to deal with directly. Hexadecimal (hex) numbers are particularly convenient because
exactly two hexadecimal digits make up one byte, each hex digit representing 4 binary digits (4 bits) as shown
here;
Matrix Orbital
LK204-25
23
Table 10: Hex Value Table
Binary
0000
0001
0010
0011
0100
0101
0110
0111
Hex
0
1
2
3
4
5
6
7
Decimal
0
1
2
3
4
5
6
7
Binary
1000
1001
1010
1011
1100
1101
1110
1111
Hex
8
9
A
B
C
D
E
F
Decimal
8
9
10
11
12
13
14
15
Based on the table, the byte 01001011 can be represented in hex as 4B, which is usually written as any
of 4Bh, 4BH, 4B hex or 0x4B.
The numbers can also be expressed in decimal form if preferred.
7.3.1
ASCII Characters
Since computers deal internally with numbers only, but externally with both letters and numbers, several
schemes were developed to ’map’ written characters to numeric values. One such scheme has become
universal, the American Standard Code for Information Interchange, or ASCII. ASCII tables are readily
available from a number of sources. A few examples will do here;
Table 11: Example of an ASCII Table
The letter
The letter
The number
The number
A
a
0
9
Has a value of
Has a value of
Has a value of
Has a value of
65 Decimal or
97 Decimal or
48 Decimal or
57 Decimal or
41 Hex
61 Hex
30 Hex
39 Hex
This gives rise to the possibility of confusion when parameters are being set on the display For example,
the GPO ON and OFF commands use a number to indicate which GPO is being controlled. We’re told that
acceptable values are 0 to 6. All such parameters must use numeric values (i.e., the actual byte values). If
we send the ASCII number 0 by mistake it will actually give the value 48 decimal (30 hex) to the parameter,
which is wrong.
In the tables given in the following sections ASCII characters are shown as ’A’, with single quotes.
7.4 Text Commands
Syntax in the tables below is given in hex, decimal and decimal with ASCII, in that order, one per line.
Matrix Orbital
LK204-25
24
Table 12: Text Commands
Command
Auto line wrap on
Syntax
FE 43
254 67
254 ’C’
FE 44
254 68
254 ’D’
FE 51
254 81
254 ’Q’
Default
On
Auto scroll off
FE 52
254 82
254 ’R’
Off
Set cursor position
FE 47 [col] [row] 254 71
[col] [row] 254 ’G’ [col]
[row]
N/A
Send cursor home
FE 48
254 72
254 ’H’
Underline cursor on
FE 4A
254 74
254 ’J’
FE 4B
254 75
254 ’K’
FE 53
254 83
254 ’S’
FE 54
254 84
254 ’T’
Auto line wrap off
Auto scroll on
Underline cursor off
Block cursor on
Block cursor off
Matrix Orbital
On
Off
Off
Notes
Enables
line
wrapping
(not
word wrap).
Disables
line
wrapping.
Enables scroll at
bottom of screen.
Text will push
display up one
line to make room
for new line.
Disables
auto
scroll. Text will
wrap to top left
and
overwrite
existing text.
Moves
cursor
to the specified
column and row.
The cursor marks
the text insertion
point in this and
all commands.
This
command
moves the cursor
to the top left of
the display area.
Turns on the underline cursor.
Turns off the underline cursor.
On
LK204-25
Turns on the
blinking
block
cursor.
Turns off the
blinking
block
cursor.
25
Command
Cursor left
Syntax
FE 4C
254 76
254 ’L’
Cursor right
FE 4D
254 77
254 ’M’
Default
Notes
Moves the cursor one position
to the left. If the
cursor is already
at the beginning
of a line it will
move to the end
of the other line.
Moves the cursor one position
to the right. If the
cursor is already
at the end of a line
it will move to the
beginning of the
other line.
7.5 Keypad Interface Commands
Table 14: Keypad Interface Commands
Command
Auto repeat mode on
Syntax
FE 7E [0x00|0x01] 254
126 [0|1]
254 ’~’ [0|1]
Default
Off
Auto repeat mode off
FE 60
254 96
254 ’‘’
FE 41
254 65
254 ’A’
Off
FE 4F
254 79
254 ’O’
Off
Auto transmit key presses
on
Auto transmit key presses
off
Matrix Orbital
On
LK204-25
Notes
Applies to keypad
only.0x00
= 200 ms typematic,0x01
=
key down/key up
codes sent.
Applies to keypad
only.
Sets auto transmit
mode for keypad.
Key presses are
transmitted
to
host
without
polling.
Up to 10 key
presses buffered
until polled.
26
Command
Clear key buffer
Poll keypad
Set debounce time
Syntax
FE 45
254 69
254 ’E’
FE 26
254 38
254 ’&’
Default
N/A
Notes
Clear unread key
presses.
N/A
FE 55 [time]
254 85 [time]
2 54 ’U’ [time]
52ms
Returns buffered
key presses to
application. Returns 0x00 if
no key presses.
High order bit
set unless this is
the last/only key
press.
Resolution: 1 =
0.6554 ms [time]
is a numeric multiplier.
7.6 Bar Graphs and Special Characters
Table 16: Bar Graphs and Special Characters
The commands in this section are used to define and display bar graphs and special characters.
Command
Initialize thick vertical bar
graph
Initialize thin vertical bar
graph
Initialize horizontal bar
graph
Define custom character
Matrix Orbital
Syntax
FE 76
254 118
254 ’v’
FE 73
254 115
254 ’s’
FE 68
254 104
254 ’h’
FE 4E [c][8 bytes]
254 78 [c][8 bytes]
254 ’N’ [c][8 bytes]
LK204-25
Notes
Initializes the user character set to
make wide vertical bar graphs.
Initializes the user character set to
make narrow vertical bar graphs.
Initializes the user character set to
make horizontal bar graphs.
Defines one of 8 custom "user" characters. Character number is [c] between 0x00 and 0x07. The 8 bytes
are described in section 5.1.6.
27
Command
Draw vertical bar graph
Syntax
FE 3D [col][length]
254 61 [col][length]
254 ’=’ [col][length]
Draw horizontal bar graph
FE 7C [c][r][d][length ]
254 124 [c][r][d][length]
254 ’|’ [c][r][d][length]
Initialize large digits
FE 6E
254 110
254 ’n’
FE 23 [col] [digit]
254 35 [col] [digit]
254 ’#’ [col] [digit]
Place large digits
Notes
Draws a vertical bar graph at column
[col] of length [length]. Length is
measured in pixels (0x00 to 0x14).
User must first use the ’v’ or ’s’
command to initialize characters.
Draws a horizontal bar graph starting at column [c] on row [r] with direction [d] (0 is right, 1 is left) of
length [length]. Length is measured
in pixels (0x00 to 0x64 if starting in
column 1). User must first use the
’h’ command to initialize characters.
Initializes the user character set to
make large digit
Place large digit number [digit] in
column [col] of the display. Cursor
moves to bottom right of large digit.
[digit] is 0x00 to 0x09, [col] is 0x01
to 0x12 (i.e. 1 to 18 decimal).
7.7 Miscellaneous Commands
Table 18: Miscellaneous Commands
Command
Clear display
Syntax
FE 58
254 88
254 ’X’
Default
N/A
Set contrast
FE 50 [contrast] 254 80
[contrast] 254 ’P’ [contrast]
0x80
128
Matrix Orbital
LK204-25
Notes
Clears screen of
text and graphics,
places text cursor
at top left.
Sets display contrast.
Compensates for viewing
angle. Contrast
is a value between
0 and 255 (hex 0
to FF). Larger =
darker.
28
Command
Backlight on
Syntax
FE 42 [minutes]
254 66 [minutes]
254 ’B’ [minutes]
Default
On
Backlight off
FE 46
254 70
254 ’F’
FE 56 [gpo #]
254 86 [gpo #]
254 ’V’ [gpo #]
On
General purpose output on
FE 57 [gpo #]
254 87 [gpo #]
254 ’W’ [gpo #]
Off
Read module type
FE 37
254 55
254 ’7’
FE 36
254 54
254 ’6’
see table
General purpose output off
Read version number
Matrix Orbital
Off
Notes
Backlight
will
stay on for [minutes]. If [minutes]
= 0 backlight
will
stay
on
permanently.
Maximum value
for [minutes] is
100.
Turns backlight
off.
Turns a general
purpose output
OFF. [gpo #] may
be from 1 to 6.
Turns a general
purpose output
ON. [gpo #] may
be from 1 to 6.
Reads the module
type.
Reads
the
firmware
version number of
the module.
LK204-25
29
8
Appendix: Specifications and Options
8.1 Specifications
Table 20: Environmental Specifications
Standard Temperature Extended Temperature
0◦ C to +50◦ C
-20◦ C to +70◦ C
◦
◦
-20 C to +70 C
-40◦ C to +85◦ C
20 to 80% non condensing
10 to 55 to 10 Hz (Frequency)
1.0 mm (Total Amplitudes)
30 minutes (Duration)
X, Y, Z each direction
593 m/S2 , 10 mS
Operating Temperature
Storage Temperature
Operating Relative Humidity
Vibration (non-operating)
Shock (Non-operation)
Table 21: Electrical Specifications
Supply Voltage
Supply Current
Supply Backlight Current
4.75 - 5.25 Vdc (optional 8 - 15 VDC)
9 mA typical
115 mA typical
Table 22: Optical Characteristics
Number of Characters
Matrix Format
Display Area
Character Size
Character Pitch
Line Pitch
Dot Size
Dot Pitch
LED Backlight Life
Color of Illumination
Matrix Orbital
40 (20 characters by 2 lines)
5 x 7 with underline
82.2 x 18.20 mm XxY
2.4 x 4.7 mm (XxY), not including underline
3.55 mm
5.35 mm
0.55 x 0.55 mm (XxY)
0.6 x 0.6 mm (XxY)
100,000 hours typical
Yellow Green
LK204-25
30
Figure 16: Physical Layout
Matrix Orbital
LK204-25
31
8.2 Options
Table 23: Options Available on LK204-25
Extended Temperature
Wide Voltage
Wide Voltage with Efficient Switching Power Supply
9
E
V
VPT
Appendix: Glossary
Table 24: Appendix: Glossary
ASCII
Backlight
Binary Number
Bit
Bitmap
Byte
CCFL
Configuration
Contrast
Matrix Orbital
American Standard Code for Information Interchange.
A 7 bit binary code representing the English alphabet, decimal numbers and common punctuation marks.
Also includes control characters such as carriage return or end of text. An 8 bit superset of the standard
ASCII codes is often used today to include foreign
characters and other symbols. These supersets are often called extended ASCII character sets.
A backlit display is illuminated from behind to provide
nighttime and improved daytime readability.
The (data and signaling) bit transmission rate of an RS232 device.
A number written using binary notation which only
uses zeros and ones.
A representation, consisting of rows and columns of
dots, of a graphics image in computer memory. The
value of each dot (whether it is filled in or not) is stored
in one or more bits of data.
A grouping of eight binary bits.
Cold Cathode Fluorescent Lamp. A high brightness
backlighting source consists of a fluorescent tube powered by a high voltage A.C. source.
The way a system is set up, or the assortment of components that make up the system. Configuration can
refer to either hardware or software, or the combination of both.
The ratio of luminance between the light state of the
display to the dark state of the display.
LK204-25
32
Controller
DB-9
Firmware
Font
Font Metric
Hexadecimal
I2 C
Interface
LCD
Module Value Type
Pixel
Pre-Generated Fonts
Primitive
RS-232
Matrix Orbital
The micro-controller or PC used to control the Matrix
Orbital display unit.
The designation of a connector used in the RS-232 interface: 9 pin connector.
Software (programs or data) that has been written onto
read-only memory (ROM). Firmware is a combination of software and hardware. ROMs, PROMs and
EPROMs and flash EEPROMs that have data or programs recorded on them are firmware.
A design for a set of characters. A font is the combination of typeface and other qualities, such as size, pitch,
and spacing.
A definition of where font is to be placed, such as margins and spacing between characters and lines.
Refers to the base-16 number system, which consists
of 16 unique symbols: the numbers 0 to 9 and the letters A to F. For example, the decimal number 15 is
represented as F in the hexadecimal numbering system. The hexadecimal system is useful because it can
represent every byte (8 bits) as two consecutive hexadecimal digits. It is easier for humans to read hexadecimal numbers than binary numbers.
Short for Inter-IC, a type of bus designed by Phillips
Semiconductors in the early 1980s, which is used to
connect integrated circuits (ICs). I2 C is a multi-master
bus, which means that multiple chips can be connected
to the same bus and each one can act as a master by
initiating a data transfer.
A means by which two systems interact.
Liquid Crystal Display.
This refers to the model number of the module.
The smallest individually controllable element of a
display.
Pre-determined fonts which can be downloaded into
graphic liquid crystal displays.
A low-level object or operation from which higherlevel, more complex objects and operations can be
constructed. In graphics, primitives are basic elements,
such as lines, curves, and polygons, which you can
combine to create more complex graphical images.
Short for recommended standard-232C, a standard interface approved by the Electronic Industries Association (EIA) for connecting serial devices.
LK204-25
33
Scroll
Serial Number
Serial Port
Version Number
Volatile Memory
Matrix Orbital
To view consecutive lines of data on the display screen.
The term scroll means that once the screen is full, each
new line appears at the bottom edge of the screen and
all other lines move up one position.
A number that is one of a series and is used for identification of the module.
A port, or interface, that can be used for serial communication, in which only 1 bit is transmitted at a time.
This refers to the firmware revision number of the
module.
Temporary memory. Once the power supply is turned
off volatile memory is then erased.
LK204-25
34
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