PC Compatible Mode

In this Mode, the C-64 keyboard acts like a standard PC Keyboard, keeping the original layout as far as possible, but also remapping non-existent ones to modern functions.

Considering the C-64 had no Numeric KeyPad, nor complete set of Function Keys (F1 a F12),  the paradigm is similar to “60%” Keyboards, using Special Function Keys (Fn y Fn2) allowing the same key having more than one function.

In the following pic, the PC Mode layout is shown. This is the mode when you plug your keyboard. 

In light brown you can see the keys having different assignments than the original C-64 Keyboard, as described below.


  • RUN/STOP turns to Left ALT.
  • (Left Arrow) turns to ESCAPE, or ~  (diacritic) if SHIFT is held.
  • £ turns to \ (inverted slash), o | (pipe) if SHIFT is held.
  • 0 key is also ^ (circumflex accent) if SHIFT is held.
  • (Up Arrow) moves the cursor up.
  •  (Minus) is also _ (underscore) if SHIFT is held.

The rest of the exclusive C-64 keys: @ (at),  * (asterisk),  = (equal) and + (add) will work as such, regardless SHIFT being held or not.


The Cursor keys (↑/↓) y (←/) will work down () and right () unless right SHIFT is being pressed as described below.

LEFT CONTROL and TAB in one key.

This is maybe one of the coolest feature of QMK Firmware. Due to the fact that the CONTROL key is located ijn the same place than TAB in a regular PC Keyboard, Keymmodore-64 implements a dual role fot this key:

If you tap it (meaning press and release without pressing another key) it will work as a TAB; however if you press and hold, and press another key, it will work as a CONTROL allowing the combination with other keys, like CTRL+C, CTRL+V, etc. Cool uh?


The Left SHIFT works like any standard PC Keyboard, allowing access to capital letters and additional characters as usual.

The SHIFT LOCK key is actually the same than the Left SHIFT, but with a mechanical lock so it is not the same than a real CAPS LOCK, affecting also the 0 a 9 keys.

COMMODORE (C=) key as “Fn” key

The key with  the C= symbol on it, generally called «Commodore Key», works as a Modification Fn key allowing to access to a different layers and function like the “60%” Style Keyboards.

In the following diagram you can see in white which keys will change its function when Fn  (C=) is pressed. Some functions are already in the legends of the keys, and others are added to better productivity.

  • 1 to 0 keys, as well as + y will work as F1 to F12
  • HOME key works as END
  • INST/DEL key works as INSERT as the top legend.
  • and RESTORE keys works as PAGE UP y PAGE DOWN respectively.
  • and cursor keys work up () and left (←) respectively, as the top legend described.
  • Q and E, as well as U and O keys, work as PAGE UP and PAGE DOWN respectively.
  • WASD and IJKL work as directional cursor  ↑ ←↓ → respectively.
  • key work as ` (grave tilde), and ~ (diacritic).
  • : (colon) and ; (semicolon) work as { and } (brackets) respectively.
  • P key works as PRINT SCREEN.
  • @ (at) key works enabling and disabling SCROLL LOCK.
  • * (asterisk) key works enabling and disabling NUM LOCK  (very important for joysticks). 
  • < (less than) y (greater than) decrease and increase audio volume respectively (*).
  • / (slash) mutes the audio output (*).
  • C fires the Calculator (*).

(*) If supported by the Operative System.

Switching to Emulator Compatibility Modes.

Pressing C= Key with F1, F3 or F5 switch to different Emulators layouts depending what computer you want to emulate: 

  • C-64, VIC-20, 16, 116 and Plus/4 Mode: Keep Fn (C=) pressed and press F1.
  • C-128 Mode: Keep Fn (C=) pressed and press F3.
  • PET Graphics Keyboard: Keep Fn (C=) pressed and press F5.
    • PET Business Keyboard: Once you have switched to Graphics Keyboard, you can switch to Business Keyboard by pressing again Fn (C=) and F5.

To avoid any confussion, it is not possible to switch between two Emulator Modes (except Graphics to Business in PET) . You have to switch back to PC Compatible Mode first by pressing C= and CONTROL. Also remember you need the configuration keyboard layout files for your emulator to work properly.


The RIGHT SHIFT besides being a regular Shift for most of the keys, works also a a second modification key Fn2 as explained:

  • The Cursor and keys work Up () y left (←) respectively, as the top legend describe (in the same way C-64 does).
  • The F1, F3, F5 and F7 function keys work as F2, F4, F6 and F8, as the top legend describe (in the same way C-64 does).

You can combine these with Left Shift to get Shifted Function keys, eg: if you want to press Shift + F6 you can do it both ways: 

  1. Right Shift + Left Shift + F5/F6.
  2. C= key + (any) Shift + 6.