This project is designed to allow a modern USB keyboard to be used with a Commodore C16 or Commodore C64 instead of the original Commodore keyboard.
It is intended to be plugged into the internal 20-pin keyboard connector.
This was forked from C128 USB Keyboard project, initially forked from https://github.com/Hartland/C64-Keyboard but I made lots of both hardware and software modifications to achieve my goal of supporting full C128 keyboard.
I have kept only USB section as PS/2 keyboards are becoming retro themselves.
This project requires SEEED XIAO SAMD21, which has USB-C socket. USB-C keyboards are rare yet. I use OTG USB-A (female) to USB-C (male) adapter to connect standard PC keyboard.
-- Maciej 'YTM/Elysium' Witkowiak
- can be used with any USB keyboard, including wireless ones
- keyboard maps switchable on the fly
- OLED display support
- adapter can be plugged directly into keyboard port
Use KiCad to open the project in kicad-c128keyb folder.
In the kicad-c128keyb/plots you will find ready to use Gerber files for manufacturing as well as schematic
The easiest way to order PCBs is through the shared project page on PCBWAY. Simply click this link and add to your cart.
- SEEED XIAO SAMD21 (important: SAMD21, not RP2040)
- U1: MT8808
- U2: 74HCT595
- C1, C2: 100n capacitors
- pin headers and sockets
- 128x32 SSD1306 I2C OLED display (optional)
C16 option:
- use J5 as keyboard connector
- J4 to provide power, connect +5V to the square pad
- don't install Q1 and R1
C64 option:
- use J2 as keyboard connector
- Q1: 2N3904 transistors (or any other NPN, like S9013)
- R1: 10K resistors
There is no +5V pin connected to keyboard connector in C16. Connect +5V from anywhere inside computer (e.g. one of the legs of C22 - yellow square on the photo below) to the square pad of J4.
Install Q1 and R1.
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SEEED XIAO uses slightly modified USBHOST Arduino library SEEED/C64_USB_Host_Library_SAMD. This directory will need to be copied into the Arduino library directory.
-
SEEED XIAO will need its board driver installed into the Arduino IDE. See manufacturers instructions.
Use Arduino IDE to compile and flash relevant sketch from SEEED/C16_keyboard/C16_keyboard.ino.
Use Arduino IDE to compile and flash relevant sketch from SEEED/C16_keyboard/C64_keyboard.ino.
C64 firmware is a trimmed-down version of C128 USB keyboard firmware with special C128 keys and joystick simulation removed (not possible with MT8808).
Key maps are defined in SEEED/C16_keyboard/keymaps.h and SEEED/C64_keyboard/keymaps.h.
You can modify existing ones or add your own.
If you add a new keymap you need to add it to keymaps[] array at the bottom of that file. The first key map in that array is the default one.
This is a mixture of C16/Plus4/C64 and Vice layout.
| USB key | C16 key |
|---|---|
| ESC | RUN/STOP |
| F1 | F1 |
| F2 | F4 (shift+F1) |
| F3 | F2 |
| F4 | F5 (shift+F2) |
| F5 | F3 |
| F6 | F6 (shift+F3) |
| F7 | HELP |
| F8 | F7 (shift+HELP) |
| ` ~ | ESC |
| - | + |
| + | - |
| [ | @ |
| ] | * |
| \ | = |
| ; | : |
| ' " | ; |
| Tab | CTRL |
| Caps lock | RUN/STOP |
| Home | CLR/HOME |
| End | RUN/STOP |
| Delete | DEL |
| Backspace | DEL |
| Insert | POUND |
| Page down | (left arrow) |
| Page up | (up arrow) |
| left CTRL | C= key |
| left Windows | C= key |
| right Alt | POUND |
| right Windows | POUND |
| right CTRL | = |
| Print Screen | reset MT8808 switchboard |
| Scroll Lock | Shift Lock |
| Pause | switch to next keymap |
| (keypad) | digits 1-9,0 |
| (cursors) | cursors |
| USB key | C16 key |
|---|---|
| ESC | ESC |
| F1 | F1 |
| F2 | F4 (shift+F1) |
| F3 | F2 |
| F4 | F5 (shift+F2) |
| F5 | F3 |
| F6 | F6 (shift+F3) |
| F7 | HELP |
| F8 | F7 (shift+HELP) |
| ` ~ | (left arrow) |
| \ | POUND |
| Tab | CTRL |
| Caps lock | RUN/STOP |
| Home | CLR/HOME |
| End | RUN/STOP |
| Delete | DEL |
| Backspace | DEL |
| left CTRL | CTRL |
| right CTRL | CTRL |
| left Windows | C= key |
| Print Screen | reset MT8808 switchboard |
| Scroll Lock | Shift Lock |
| Pause | switch to next keymap |
| (keypad) | digits 1-9,0 |
| (cursors) | cursors |
As you would expect from standard keycaps, e.g. SHIFT+2 is '@', not '"'.
This layout works best if you have muscle memory of the original keyboard.
| USB key | C64 key |
|---|---|
| ESC | RUN/STOP |
| F9 | F1/F2 |
| F10 | F3/F4 |
| F11 | F5/F6 |
| F12 | F7/F8 |
| Print Screen | reset MT8808 switchboard |
| Scroll Lock | Shift Lock |
| Pause | switch to next keymap |
| Insert | POUND |
| Home | CLR/HOME |
| Page Up | RESTORE |
| End | RUN/STOP |
| (keypad) | digits 1-9,0 |
| left CTRL | C= key |
| left SHIFT | left SHIFT |
| right SHIFT | right SHIFT |
| AltGr | RESTORE |
As you would expect from standard keycaps, e.g. SHIFT+2 is '@', not '"'.
Other changes:
- both left and right CTRL mapped to CTRL
- both left and right Windows mapped to C= key
- AltGr is RESTORE