C64 VICE Front-End

Posted on Feb 4, 2014

The aim of this project was to create a front-end for Commodore 64 emulation using VICE. One of the primary problems with emulators (especially for machines from the `80s) is that there was no standard keyboard arrangement. In this project I took a broken Commodore 64 computer and replaced the motherboard with a PIC microcontroller based board whi

C64 VICE Front-End
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ch interfaces the keyboard and both joystick ports (including ADC for the paddles) to a modern full-speed USB 2. 0 interface. The board is designed to fit inside the original Commodore 64`s `breadbox` case without requiring any modification to the original machine. In fact it is possible to fit this interface and at a later point remove it and replace it with the original motherboard (we have to preserve what we have!) The Commodore 64 keyboard is a straight-forward matrix keyboard with 8 columns and 8 rows giving a total of 64 keys. There is also an additional RESTORE key which (in the original machine) was wired to the CPU to act as a non-maskable interrupt key (or `break` key). In order to wire the keyboard up to the PIC controller I made a simple breakout adaptor for the keyboard connector (a 20-pin SIP female connector) and wired it to my PIC USB reference board (this board is actually a pin-compatible clone of the PICDEM FS USB board which I made myself): The reference board is useful because it acts as a `known working` USB implementation (this is so you know that only your software is wrong when it doesn`t work - otherwise debugging USB code can be a little tricky). Once connected I was able to test the keyboard and the method for connecting it to the PIC. I also decided to test the configuration of the keyboard matrix since this is very important for detecting `ghost keys` as you will see later in this article....

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