Commodore 128 Power Helper
The aim of this project is to replace the orignal power supply on a Commodore 128 with a modern ATX power supply.
The project makes use of an ATTiny85 for several features:
- Power on/off with the RESTORE key
- Generate Time Of Day clock (60Hz)
- Ability to switch Kernel ROM banks if modded for JiffyDOS
- Connected via serial user port to power off and switch ROM banks and any other cool features that will fit in 8K.
This modification, while not overly difficult, is not for everyone. It requires a good working understanding of eletronics, and skill with soldering. It also requires the ability to flash the ATTiny85 micro controller and build a simple circuit.
Also, by switching to an ATX power supply, we must live without the 9VAC power that was orignally supplied. This impacts the following areas:
- User port won't have 9VAC to offer any periphials, so some devices like modems may not work
- Tape drive motor won't have power
- Time of day clock won't receive 60Hz from AC power, so it must be simulated
Check under the hardware folder for instructions, schematics and photos.
I've only tried this on my C=128, but might also add it to one of my C=64's.
The same code and circuit should work on both.
This project uses the software serial routines from https://github.com/blalor/avr-softuart
The code has a Makefile and should compile under most versions of Linux with the avr-gcc tool chain and avrdude installed. It also compiled under Atmel Studio 6.2 for me.
WARNING: This project uses the /RESET pin, so once it's programmed via ISP, you need to high-voltage clear the fuse to reprogram the device.