Repair & Schematics
Commodore VIC-20

Programmers Aid (VIC-20)

6min

The Programmers Aid cartridge was a cartridge that helped you write programs a little quicker.

Programmer's Aid Cartridge
Programmer's Aid Cartridge
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With the cartridge inserted, on first boot, you see nothing different. You will be presented with the CBM BASIC V2 screen.

Loading Programmers Aid

Type SYS 28681 and press Return. This will load the cartridge program and display Programmers' Aid.

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Basic Shortcuts

Now you have some really useful shortcuts.

Keys

Function

F1

LIST

F3

RUN

F5

GOTO

F7

INPUT

Shift + F1 (F2)

MID$(

Shift + F3 (F4)

LEFT$(

Shift + F5 (F6)

RIGHT$(

Shift + F7 (F8)

CHR$(

Remapping Function Keys

Say we want F1 to be PRINT instead of LIST, we can do this easily by typing the following command:

BAT
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And hitting enter. Now when we press F1 it would type PRINT.

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Commands

The Programmers Aid also has many commands you can type into BASIC to perform tasks faster.

Command

Description

AUTO [NUM]

Generate line numbers automatically, incrementing by [NUM]

CHANGE "OLD", "NEW"

Replace all occurrences of a given string "OLD", with "NEW"

DELETE [NUM]

Delete line [NUM] from a program

DUMP

Display the values of all variables

EDIT

Use the EDIT set of function keys

FIND "TEXT"

Locate all occurrences of a given string "TEXT"

HELP

Indicate the location of an error

KEY

Display or assign a string to a function key

KILL

Disable all additional commands

MERGE

Load a program, combining it with the current one

OFF

Disable STEP or TRACE mode

PROG

Use the PROG set of function keys

RENUMBER [NUM]

Renumbers all line numbers to go up by 10, starting at [NUM]

STEP

Eanbles stepping, so when RUN happens, program will pause every line until Shiftis pressed to move one line at a time.

TRACE

Display the line number as a program is executed at top right.

For example, DELETE 20 will delete the line 20.

Typing AUTO 10 will start entering program lines and every time you press Return it automatically adds 10 to the next line, so it would start at 10, then the next line would be 20, 30 and so on. Pressing enter on a blank line will exit.

Control Commands

As well as BASIC commands, there are useful screen commands using the Control key.

Keys

Description

Ctrl + A

Scroll up a program list

Ctrl + E

Cancel quote and insert modes

Ctrl + L

Erase characters after cursor on same line

Ctrl + N

Erase all characters in program after cursor

Ctrl + Q

Scroll down a program list

Ctrl + U

Erase all characters on cursor line

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