I have forked this version from https://github.com/Hartland/C64-Keyboard for two reasons:
- design PCB to connect PS/2 keyboard with MT8808 and Arduino Micro Pro solution to C128D, directly to the keyboard port
- provide symbolic, rather than positional, mapping for the keys
Everything you need for this version is in PS2/C128_keyboard_MT8808 folder.
I have cleaned up the code and added named key value definitions to the keymap file for easier mapping.
Have fun!
-- Maciej 'YTM/Elysium' Witkowiak
This project uses external submodule with Arduino Micro Pro symbol and footprint.
Clone it with all submodules using:
git clone --recurse-submodules https://github.com/ytmytm/C64-Keyboard.gitUse KiCad to open the project in PS2/C128_keyboard_MT8808/PCB folder.
Ready for use Gerber files for circuit board v1.0 are in PS2/C128_keyboard_MT8808/PCB/gerber folder.
Use Arduino IDE to compile and flash the code from PS2/C128_keyboard_MT8808/Firmware folder.
Parts:
- 26-wire flat ribbon cable
- 26-pin ribbon cable connectors (male for PCB, female for crimping on the cable)
- DE25 male crimp connector for ribbon cable
- MT8808
- Arduino Micro Pro
- (optional) PS/2 socket
- (optional) 28-pin and 24-pin sockets
Assembly:
- align red (first) wire with triangular mark on the female connector and crimp it
- separate 26th wire and remove it from the cable, cut it off as close as possible to the already crimped connector
- now the cable can be aligned and crimped in the DE25 connector; aligh red (first) wire with the mark on connector, confirm that it goes to pin 1
- solder parts on the PCB, start with lowest profile components first (sockets, MT8808, male 26-pin connector)
You can skip over transistor and resistor and connect pin 3 from the cable directly to Arduino pin 16 using a jumper. This part would be required on C64, but C128 has separate circuitry for RESTORE key, it's not tied directly to /NMI line.
Add two wire connections that I forgot to put on PCB in version 1:
- pin 24 to A0 (40/80 key)
- pin 25 to A1 (CAPS key)
| C64/128 key | PS/2 key |
|---|---|
| C= | Windows |
| RUN/STOP | ESC, END, left ALT |
| RESTORE | TAB |
| ARROW LEFT | ` (tilde) |
| ARROW UP | ^ (SHIFT+6) |
| @ | @ (SHIFT+2) |
| DEL | DEL, BACKSPACE |
| CLR/HOME | HOME |
| * | * (SHIFT+8) |
| POUND | \ |
| PS/2 key | action |
|---|---|
| F9 | symbolic keymap (default) |
| F10 | positional keymap |
| F11 | C128 CAPS toggle |
| F12 | C128 40/80 toggle |
| CAPS LOCK | SHIFT LOCK toggle |
| SysRq | reset MT8808 |
Left (right too?) SHIFT release must be after shifted key release. Otherwise the shifted key is stuck until exact the same sequence is entered again. It's quite annoying for '@' and ':'.
To do in PCB version 2:
- connect C128 40/80 line (pin 24) to A0
- connect C128 CAPS line (pin 25) to A1
- connect RESTORE line (pin 3) directly to pin 16, no need for transistor and resistor there (true for 5V Arduino, certainly not for SEEDUINO)
- correct parts alignment so that mounting holes are not obscured
- use PS/2 socket footprint
- use DB25 male socket footprint for direct connection
- use 1x25 footprint for C64 compatibility
- +5V jumper between Arduino VCC and +5V net (serial port, PS/2 port and DE25 pin 4)
To do for MT8812/MT8816 version:
- handle extra C128 keys using DE25 pins 21/22/23 (K0/K1/K2)
To do for SEEDUINO version:
- there is not enough pins, I/O expander or latch is needed, 74'595 is enough for this
- 3x transistor + 3x 10K resistor for /RESTORE, 40/80 and CAPS required
This project is designed to allow a PS2/USB keyboard to be used with a Commodore 64 in place of the original Commodore keyboard.
-
PS2KeyAdvanced Arduino library for use with PS2 keyboard. Install through the IDE library manager
-
SEEED XIAO uses slightly modified USBHOST Arduino library (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.
-
DUE also uses a modified USBHOST library but it is included with the source and does not need to be installed in the library directory.
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Arduino Uno, Nano, DUE, or SEEED XIAO. SEEED XIAO or DUE required for USB keyboard
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MT8808, MT8812 or MT8816 Analog Switch Array
-
20 pin female header or male header with cable (PATA cable will work)
-
Arduino shield PCB.
- Any universal PCB that will line up correctly
-
PS2 keyboard
- matching socket or cut/strip and directly wire
-
USB keyboard - SEEED XIAO is highly recommended as the DUE is overkill for this project
- Requires SEEED XIAO or DUE. In most cases, the SEED requires USB Type C to USB A or Micro Type B cable/adapter
- Keyboards that connect through internal USB hubs are not supported.This is a limitation of the USBHost library
- Restore (NMI) key requires a NPN transistor (2n3904 suggested) and resistor (10K)
-
KEYBIN.PDF
- MT88XX AY/AX. These are the hard wired Commodore keyboard header position values used in keyboard mapping.
- The position values are placed on the keymap where the PS2/USB keyboard value matches the Commodore key desired.
- The AX2-1-0 AY2-1-0 and logic hole hole columns are for reference and not needed to make keymaps.
- The logic hole column only applies to the MT8812-16.
-
DEFAULTKEY.TXT
- Key map of special function keys (EX. C= key mapped to Windows key)
-
USB_KEY_CODES.TXT
- Public Domain copy of USB HID scan codes.
-
Schematic PDF files
- Include wiring charts and are located in the PS2 and USB folders under the appropriate board type
- MT8808 and MT8812-16 are separate due to a different MT88xx pinouts
-
PS2 keyboards use the PS2KeyAdvanced library. -Use Manage Library to search for and install PS2KeyAdvanced.
-
USB Keyboards use the included modified USBHOST.
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Using the Arduino IDE upload the sketch: C64_keyboard.ino into your Arduino.
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SYSTEM OPTIONS ARE LOCATED IN THE C64KEYBOARD.H HEADER FILE. THE MT8808 DEFINITION IS VERY IMPORTANT. SET TO TRUE IF USING A MT8808 OR FALSE IF USING MT8812-16.
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The Arduino UNO, Nano, and SEEED can be powered from the C64 keyboard header Pin 4
-
The Arduino DUE CANNOT BE POWERED FROM PIN 4!! Use the + side of C10 (+10V) connected to the DUE barrel power connector instead.
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Create spreadsheet/program to automatically create key maps
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Publish pre-compiled binary files
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Updated and cleaned up all schematics and documents. All wiring charts are now on the schematics.
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DUE has been brought out of archive status and will be part of future updates.
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Add SEEED XIAO board for USB keyboards
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Document DUE is for archive only
- USB IDE library requirement removed
- USB module published
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Code rewrite using PS2KeyAdvanced library
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Several bugs have been fixed
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Speed and reliability have been greatly improved
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Up to 2 key maps can be stored and hot swapped with assigned keys (Default F9-F10)