Real C64 keyboard to USB Adapter Arduino Firmware

Arduino Pro Micro code that allows you to use a real C64 Keyboard via USB, not just with Vice on Mac/Windows/Linux/RetroPie, but also Ultimate64, BMC64, MiSTer FPGA, etc.

1. First version is a modification of firmware originally by DJ Sures (Synthiam.com) (c)2019 that simply fixes the cursor up to work using both left AND right shift
2. Second version changes the C= and CTRL key behaviour, and makes C= + F7 into F12 for my preference
3. The third version is mostly likely the one you want - it is a new (work in progress) rebuilt from almost ground up version that will be detected by both regular Mac/Windows/Linux AND bare-metal/FPGA such as MiSTer, BMC64 and Ultimate64. You will need the HID library for Arduino.

Uncomment the correct target machine to use your C64 keyboard with

• U64
• VICE
• MISTER
• BMC64

 ----------------------
 CONNECTIONS
 ----------------------

     C64   |  Arduino
    ==================
       20     2 - SDA
       19     3 - SCL
       18     4 - A6
       17     5
       16     6 - A7
       15     7 -
       14     8 - A8
       13     9 - A9
       12     10 - A10
       11     16 - MOSI
       10     14 - MISO
       9      15 - SCLK
       8      18 - A0
       7      19 - A1
       6      20 - A2
       5      21 - A3
       4      -N/C-
       3      1
       2      -N/C-
       1      0
    ==================

    

        ------------------------------------
        Commodore 64 keyboard matrix layout                                                                
        ------------------------------------
                                                                
        Del      Return   curl/r   F7       F1       F3       F5       curup
        3        W        A        4        Z        S        E        lSh
        5        R        D        6        C        F        T        X
        7        Y        G        8        B        H        U        V
        9        I        J        0        M        K        O        N
        +        P        L        –        .        :        @        ,
        £        *        ;        Home     rshift   =        ↑        /
        1        ←        Ctrl     2        Space    C=       Q        Stop

// Uncomment if you wish to debug keyboard through serial monitor at 115200 baud
//#define DEBUG