1.2 KiB
1.2 KiB
[DRAFT] Design for the MicroCardiograph microprocessor trainer
The MicroCardiograph uses memory-mapped IO.
Memory map
| Address | Used for... |
|---|---|
| 00 to 19 | display (5x5) |
| 1A | pointer to display memory |
| 1B | keypad: value of latest key pressed |
| 1C | reserved for future use (bank switching flag) |
| 1D | initial IP |
| 1D to FE | free |
| FF | * ROM (unwriteable) pointer to initial IP |
* Not implemented yet
Peripherals
Keypad
The value of the latest keypress on a hex keypad is stored at $1B.
The keypad uses the same layout as the COSMAC VIP (and CHIP-8). The CPU simulator maps those keys onto a Qwerty set:
1 2 3 C = 1 2 3 4
4 5 6 D = Q W E R
7 8 9 E = A S D F
A 0 B F = Z X C V
The arrow keys are also mapped onto the hex keypad:
5 = ↑
7 8 9 = ← ↓ →
Keypad as monitor input
TODO