Programming Basis
A program in The HP-12C calculator is simply a sequence of keystrokes
that is stored in the calculator. Whenever you have to calculate with the
same sequence of keystrokes several times, you can save a great deal
of time by incorporating these keystrokes in a program. Then pressing
only one key the keystrokes sequence starts and the calculator does the
rest automatically!.
Creating a Program:
1) In the Platinum model, specify the Logic mode you want to use “ALG” or
“RPN pressing
or
. The Classic model always works in
“RPN” mode.
2) Press
to set the calculator to “Program” mode. In this mode, functions are not executed when they are keyed in, but instead are stored inside
the program memory. The display will show the “PRGM” indicator lit, and
the program line number (from 000 to 999) with the key codes of keystrokes.
3) Press
clear
to erase any previous programs that may be stored
inside the calculator. If you want to create a new program without erasing a
program already stored, skip this step.
4) Key in the sequence of keystrokes that conform the program.
5) When the keystrokes sequence finish, press
to set the calculator
back to “Run” mode. The display will be normal showing the stack-X registers and the “PRGM” indicator will vanish.
Running a Program:
Once a program is created, key in any data that the program uses and
just by pressing the
key, the program start and the calculator does
the rest automatically.
When a program is running, touching any key will stop execution after
the current line.
Programming Special Keys
The calculator has several special keys that only have meaning when
you are dealing with programs. Some of them are programmable and
others don’t. The not programmable ones are for reviewing or debugging a program. The programmable ones are for controlling the program execution, like display intermediate results, perform a conditional
jump o continue the execution at specific program line.
Non Programmable Commands:
Command
Description
In Program Mode:
Sets the calculator to “Run” mode and reset the program
line to 0.
In Run Mode:
Sets the calculator to “Program” mode and displaying the
current program line.
clear
In Program Mode:
Clears the program memory and stores the current logic
mode (ALG or RPN) command in program line “000”.
In Run Mode:
Sets program line to the beginning of the program memory,
program line “000”.
In Program Mode:
Advances the calculator to the next program line in the program memory.
In Run Mode:
Shows the current program line, executes it and advances
the calculator to the next program line.
In both modes, sets the calculator to the previous line in
program memory.
In both modes, followed by three digits “DDD”, sets the current program line to the designated “DDD” line in program
memory.
Programmable Commands:
Command
Description
In Program Mode:
Enters the Run-Stop command.
In Run Mode:
Starts the program execution from the current program line
in program memory.
In a Program Execution:
Stops program execution and shows the normal display
(stack-X).
In Program Mode:
Enters the Pause command.
In Run Mode:
Does nothing.
In a Program Execution:
Stops program for about 2 seconds showing the normal
display (stack-X), and then resumes the program execution.
In Program Mode:
Followed by three digits “DDD”, enters the Go to line “DDD”
command.
In Run Mode:
Followed by three digits “DDD”, sets the current program
line to the designated “DDD” line in program memory..
In a Program Execution:
Jumps the program execution to the designated program
line.
In Program Mode:
Enters the comparison command.
(stack-X ≤ stack-Y?) In Run Mode:
Does nothing.
In a Program Execution:
(stack-X = 0?)
If condition is False -the program execution skips the next
line. If True, the next line is executed.
NOTE: A running program automatically stops if a instruction
or
is executed. It also stops if an Error condition arises from a improper
operation or if any key is touched during the execution or if the next line to execute is empty.
Example: Variable Tax Rate Program
The following program calculates income tax and the net value applying different
tax rates depending on the value entered. If the value if less than or equal to a
test value, the tax rate stored in R1 is used, otherwise the tax rate stored in R2 is
used. The test value is stored in R0 .
Enter the program in the calculator following the next sequence:
(RPN mode)
Keystrokes
Display
Description
Sets the calculator in “Program” mode
clear
000,
42
001,
45 0 Recall the test amount for comparison.
002,
003,
Clear the program memory and enters the RPN
16 code in line 000.
34 Swap stack-X and stack-Y
43
34 Compare the entered value with the test value.
Execution continues at line 007 if the entered
004,43,33,008 value is less than or equal the test value.
Recall the tax rate for amounts greater than the
005,
45 2 test value.
006,43,33,008 Jump to line 008 to calculate the tax amount
Recall the tax rate for amounts of less than or
007,
45 1 equal to the test value
Calculate the tax amount applying the proper tax
008,
009,
25 rate to the entered value.
43
31 Pause execution to display the tax amount
Subtract tax amount from the entered amount
010,
30 and program stops showing the net amount.
0.00
Sets the calculator in “Run” mode
(ALG mode)
Keystrokes
Display
Description
Sets the calculator in “Program” mode
clear
000,
42
Clear the program memory and enters the RPN
26 code in line 000.
001,
44 9 Stores the input number to further use.
002,
45 0 Recall the test amount for comparison.
003,
34 Swap stack-X and stack-Y
004,
10 amount
005,
Enter multiply operation to calculate the tax
43
34 Compare the entered value with the test value.
Execution continues at line 009 if the entered
006,43,33,009 value is less than or equal the test value.
Recall the tax rate for amounts greater than the
007,
45 2 test value
008,43,33,010 Jump to line 010 to calculate the tax amount
Recall the tax rate for amounts of less than or
009,
45 1 equal to the test value
010,
25 Divide the proper tax rate by 100.
011,
36 Calculate the proper tax amount.
012,
43
31 Pause execution to display the tax amount
Change the sign of the tax amount to subtract it
013
16 from the entered value.
014,
40 Enter add operation.
015,
45 9 Recall the entered value.
Subtract tax amount from the entered amount
016,
36 and program stops showing the net amount.
0.00
Sets the calculator in “Run” mode
If the test value is $20,000; the tax rate for values less than or equal to test value
is 20%, and for grater values is 25%. What is the tax amount and the net amount
for $15,000; $20,000 and $25,000 incomes?.
Keystrokes
Type “20000”
Type “20”
Type “25”
Type “15000”
Type “20000”
Type “25000”
Display
20,000.00
Description
Type the test value and store it in R0.
20.00
Type the tax rate for values ≤ test value and store
it in R1.
25.00
Type the tax rate for values > test value and store
it in R2.
“running”
3,000.00
“running”
12,000.00
Type the Income value and run the program.
The program pauses to display the tax amount,
then continues and ends showing the net amount.
“running”
4,000.00
“running”
16,000.00
Type the Income value and run the program.
The program pauses to display the tax amount,
then continues and ends showing the net amount.
“running”
6,250.00
“running”
18,750.00
Type the Income value and run the program.
The program pauses to display the tax amount,
then continues and ends showing the net amount.
NOTE: For a complete explanation, details and program examples,
please download the HP-12C Platinum Owner’s Manual from the
Hewlett-Packard website at “www.hp.com”
As a special feature, the calculator has a very convenient Program
Execution tool to review and debug a program. To show it, expand
the calculator pressing the
key and in the "Option Selection
Menu", select the "Program Execution” option.
">
