Hello everyone,
And first of all, best wishes!
During my Christmas holidays, I set myself the goal of reusing a Macintosh Classic whose logic board was clearly beyond repair. While searching the web, I quickly came across the pico-mac project (https://github.com/evansm7/pico-mac).
The most challenging part of the project was creating the ādriverā to achieve the correct timing for the Macintosh CRT. This is now done thanks to the PIO of the Raspberry Pi Pico (RP2040), which allows precise control of HSYNC, VSYNC, and the data signals.
I also used a logic inverter so that the RP2040 signals are not directly exposed to the 5V signals of the analog board. The final result is quite satisfying!
The result:
RP2040 and logic inverter:
Next steps (depending on available free time):
Will
And first of all, best wishes!
During my Christmas holidays, I set myself the goal of reusing a Macintosh Classic whose logic board was clearly beyond repair. While searching the web, I quickly came across the pico-mac project (https://github.com/evansm7/pico-mac).
The most challenging part of the project was creating the ādriverā to achieve the correct timing for the Macintosh CRT. This is now done thanks to the PIO of the Raspberry Pi Pico (RP2040), which allows precise control of HSYNC, VSYNC, and the data signals.
I also used a logic inverter so that the RP2040 signals are not directly exposed to the 5V signals of the analog board. The final result is quite satisfying!
The result:
RP2040 and logic inverter:
Next steps (depending on available free time):
- Design and study a custom PCB featuring:
- Support for RP2040 or RP2350
- Connector for the Molex plug (39-28-1143)
- Integrated logic inverter with 100 Ī© resistors
- SD card slot (allowing two disk images)
- 5V power supplied by the analog board
- USB port for keyboard and mouse
- Study and test alternative boards offering more PSRAM (8 MB), which would be useful for running System 7.
For example, this board looks like an excellent candidate:
https://shop.pimoroni.com/products/pimoroni-pico-plus-2-w?variant=42182811942995
Will
