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.





IC1   74LS245 Octal Bus Transceiver.
IC2   W65C22 Versatile Interface Adapter
IC3   74LS00 Quad 2 input NAND Gates.
IC4     Not Present in design
IC5,IC6   74LS139 Dual 2 line to 4 line decoder.
C1,C2 0.1uF (104)  
R1 1k    
PS2 KYBD Connector      
PCB Layout
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. Compile with

64tass --m65c02 pckybd.asm -o pckybd.hex

I sell on Tindie
(c) 2021,2022,2023 Paul Bartlett