Re: PET/CBM-II keyboard interface?

From: André Fachat (
Date: 2007-09-25 21:32:32

Hi Anders,

> power supplies, a dead CBM 710 and a PET-VRF - a video interface that 
> outputs composite video or RF signal. Unfortunately it doesn't work very 
> well. On 40 column PETs, I get an almost readable picture that scrolls in 

I have built the two common PET-to-Composite adapters, even with routed PCBs, but not yet published it. Working with my selfbuilt CS/A computer (PET compatible) and a German PAL TV with composite input. Can send at the weekend.

> or one of the older ones like Nick Hampshire's or the UK PET Users Group 

This is one of the two I built

> would like to come across some ideas how to use a micro controller to
> create 
> a keyboard interface/adapter.

I have implemented a shared-RAM based keyboard interface, where one 6502 could emulate the keyboard of a PET or C64.
Should give you some ideas.

> saw something about a C128 keyboard too. I understand that I have to deal 
> with three different types of PET keyboards, but currently I have access
> to 
> all three for testing.

You mean the chicklet keyboard, graphics and business keyboards?
Basically all the same, only different key mapping.

> interfaces, I'm all ears. Will every PET (model) have its own frequencies,

Could be. They do have different timings depending on PAL or NTSC, and depending on business and graphics model at least.


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