Commodore Pet Graphics Compatibility Mode

 This mode allows to emulate the so called «Graphics» keyboards (the one with PETSCII graphics) used by the Commodore PET Series Computer. For this Mode to work properly, you are going to need the use «.vkm» files and set your emulator to use them.

The Graphics keyboard has an odd layout where every number and symbol has its own key. Besides, keys have just one PETSCII graphics instead of two, as found in C-64 Keyboard.

However, it is possible to map every key without loosing any function, and also without having to remember the original position on the PET Keyboard. Keymmodore is able to «merge» again those two keys in one, like (!/1) key, or (</,) key.

In the following diagram you can see in orange the only three keys changing its original C-64 function.

The differences with with the original PET Graphics keyboards are:

  • CTRL key works as OFF/RVS.
  • £ (pound) key works a \ (backslash).
  • RESTORE key works as second INST/DEL.
  • C= does not exist in PET Graphics Keyboard, however we will use it to access PETSCII graphics set as explained below.
  • Function Keys (F1 to F4) do not exist in PET Graphics Keyboard, therefore they have no function. 

Access to graphics PETSCII and symbols keys.

Symbols have their own keys in PET Keyboard. Keymmodore-64 creates a layer using C= key where you can access to those keys (instead of using Shift).

The PETSCII graphics character set of PET is identical to the C-64, however due to having less count of keys, the PETSCII codes are distributed using two characters per key in C-64 Keyboard. 

Keymmodore-64 implements a special feature, able to «merge» again those two PETSCII in a single key, with the same layout than the C-64. Therefore, you can access both in the usual way: The left side ones with the C= key, and the right side one with any SHIFT key (*). 

In the following diagram you can see in green the functions with C= key, and in yellow the function with any of the two SHIFT.

Remember to switch back to PC Compatibility Mode with C= and CONTROL, once you exit the emulator.

(*) Due to some key mapping limitation in Combian emulator, right PETSCII of @,+,-,* and \ keys, won’t match C-64 keyboard, matching the original PET layout instead.