The complete original Commodore Vic-20 hardware, including the CPU, recreated in a single FPGA. The design is about 1400 Xilinx slices in size, and has a gate count of about 350K gates.
It would be possible to take advantage of the re-configurable nature of FPGA’s and expand the capabilities of the original machine, for example greater colour depth, screen resolution or number of audio channels. This could even be achieved dynamically while the machine is running, and with careful mapping of the additional registers required, complete compatibility with the original could be maintained.
Particular thanks to Graham for risking his vintage machine and allowing me to stick logic analyser probes all over it.
A PS/2 keyboard interface is included, with a keymap the same as the popular ‘Vice’ software emulator. The design is believed to be complete, and I have run through lots of the examples in the original Programmers Reference Manual. It also contains a complete 6522 VHDL core which may prove useful in other machines of this vintage.
A simulation model of Vic-20 hardware Copyright (c) MikeJ – jan 2008
IMPORTANT NOTE:NO ORIGINAL ROM CONTENTS ARE IN THIS DISTRIBUTION. YOU WILL NEED THE ORIGINAL/ALTERNATIVE ROM FILES
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