6502to8501 MOS Technology 8501 replacement

The 6502to8501 is a device that allows you to use a 6502 CPU in your Commodore 16/116/Plus4 computer, it allows you to bring a dead computer back to life. The device is an adapter that interfaces a 6502 to the 8501 signals with 74xx bus transceivers in between in order to implement the AEC funcitonality. Also, the CPU port is implemented with standard 74xx logic chips. A GAL16V8 is used as a controller for the CPU.

The original MOS Technology 7501 and 8501 CPUs that are used in the Commodore TED series computers is a chip with a very high failure rate. Therefore a lot of these computers no longer function and this device will allow you to continue using the computer.

There have been replacements design for the 7501/8501 based on 6510 and 6502 CPUs. A replacement with a MOS 6510 is technically the easiest solution, because only the pinout of the CPU needs to change. However, a 6510 based replacement has a disadvantage that the CPU port cannot be implemented in a compatible way. This requires a modified KERNAL to be able to talk to serial devices such as floppy drives and is not compatible at all with many software that uses custom loaders.

The 6502to8501 is based on a 6502 CPU. While a replacement with a 6502 is technically more complicated than a 6510 replacement, the solution is fully compatible with all software.

You will receive:

• 6502to8501 adapter
• NMOS 6502 CPU is included

Compatible with:

• Commodore 16
• Commodore 116
• Commodore Plus/4

For installation in a Plus/4, the 6502 CPU cannot be installed in a socket. Therefore, if you order this, please drop me a note whether you would like to install in a Commodore 16 or Plus/4, so I can send you a 6502to8501 with a socketed 6502 or directly soldered 6502.

More information can be found on the web page of the 6502to8501.