ATMega644 ZX81
Electronic schematic
As you can see the schematic is extremely simple and in a few minutes everything can be connected on a proto board. The circuit generates a composite PAL video signal as with the original ZX81.
Finished electronic circuit
This is how the circuit I made for testing looks like. The same circuit was used for Galaksija emulation.
In operation
Video captured directly from composite output.
Downloads
| m644_zx81.hex | HEX file to burn into ATMega644 microcontroller |
| m644_zx81bb.hex | version with black border and slightly faster emulation |
| Fuses: H=0x99 L=0xE0 |