What is it?
This is a Printed Circuit board for a 6522 VIA interface to the 65C02 SBC.
Why did you make it?
I wanted to have the ability of using a PC PS2 type keyboard and some ports for attaching other devices.
What makes it special?
You cannot buy this interface elsewhere so I had to research and design a PCB I could use.
|VIA Address Decoding
|The address decoding on this board allows the VIA to occupy 1 block of 128 bytes out of 512 blocks from $0000 - $FFFF
|An excel spreadsheet showing decoding links can be downloaded here
|The D/C/W/M Monitor downloadable on the 65C02 SBC page has keybd test routines already loaded at $F000
Source code (64tass) for those routines,
courtesy Daryl Richter is available here.
64tass --m65c02 pckybd.asm -o pckybd.hex
|(c) 2021,2022,2023 Paul Bartlett