Git repository for the KiCad project
Gerber files for fabrication:
Click to download mrom64c_r1.zip
Click here for PCB assembly instructions
Click here for programming instructions
| Address in 010 ROM | Contents | Bank size |
|---|---|---|
| 0x00000 | Font 0 | 4K |
| 0x01000 | Font 1 | 4K |
| 0x02000 | Font 2 | 4K |
| 0x03000 | Font 3 | 4K |
| 0x04000 | Font 4 | 4K |
| 0x05000 | Font 5 | 4K |
| 0x06000 | Font 6 | 4K |
| 0x07000 | Font 7 | 4K |
| 0x08000 | Font 8 | 4K |
| 0x09000 | Font 9 | 4K |
| 0x0A000 | Font 10 | 4K |
| 0x0B000 | Font 11 | 4K |
| 0x0C000 | Font 12 | 4K |
| 0x0D000 | Font 13 | 4K |
| 0x0E000 | Font 14 | 4K |
| 0x0F000 | Font 15 | 4K |
| 0x10000 | BASIC | 8K |
| 0x12000 | Kernal 0 | 8K |
| 0x14000 | Kernal 1 | 8K |
| 0x16000 | Kernal 2 | 8K |
| 0x18000 | Kernal 3 | 8K |
| 0x1A000 | Kernal 4 | 8K |
| 0x1C000 | Kernal 5 | 8K |
| 0x1E000 | Kernal 6 | 8K |
Kernal and character ROM banks are binary-numbered. On the board is a pin header with a series of pins labelled F0 to F3 and K0 to K2. Open pins are high by default due to pull-up resistors. To set a low state, close a a pin pair with a jumper or otherwise.
K0, K1, and K2 simultaneously low is an illegal combination and the C64 will not boot. Do not close all three headers or set all three low together.
| Font selection | F3 | F2 | F1 | F0 |
|---|---|---|---|---|
| Font 0 | ||||
| Font 1 | 1 | |||
| Font 2 | 1 | |||
| Font 3 | 1 | 1 | ||
| Font 4 | 1 | |||
| Font 5 | 1 | 1 | ||
| Font 6 | 1 | 1 | ||
| Font 7 | 1 | 1 | 1 | |
| Font 8 | 1 | |||
| Font 9 | 1 | 1 | ||
| Font 10 | 1 | 1 | ||
| Font 11 | 1 | 1 | 1 | |
| Font 12 | 1 | 1 | ||
| Font 13 | 1 | 1 | 1 | |
| Font 14 | 1 | 1 | 1 | |
| Font 15 | 1 | 1 | 1 | 1 |
| Kernal selection | K2 | K1 | K0 |
|---|---|---|---|
| BASIC | x | x | x |
| Kernal 0 | 1 | ||
| Kernal 1 | 1 | ||
| Kernal 2 | 1 | 1 | |
| Kernal 3 | 1 | ||
| Kernal 4 | 1 | 1 | |
| Kernal 5 | 1 | 1 | |
| Kernal 6 | 1 | 1 | 1 |
Page created: 18DEC2025
Last modified: 27FEB2026