Re: PET / cbm2 timing questions...

From: André Fachat <>
Date: Mon, 20 Dec 2010 22:22:32 +0100
Message-ID: <>
> Most of my machines are pre-CRTC (8K Static PET model 2001, 32K
> Dynamic PET model 2001-N (known as a 3032 in your part of the world),
> so I was thinking primarily about them when I wrote that.

Ah I see. Those are quite interesting, they don't even have an
integrated video chip, but use a collection of TTL logic chips
to produce the - fixed timing - video output.

Here I am somewhat cheating in VICE. On reset, the CRTC emulation is
programmed according to the 3032 timing parameters, and the CPU access
is forbidden, so the values can not be changed :-)
But, same effect, correct video output with fixed timing :-)

> from CB1 level change to interrupt signal output. But my video tests and the
> > for example the No PETs Allowed demo work on the PET real and in VICE!
> Tested on older PETs too or just newer ones?

Only 8296 (my tests) and Fat-40 (i.e. with CRTC) for the demo. 
Both only work by reprogramming the CRTC chip.
You can see the test programs (with VICE screen shots :-) here


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Received on 2010-12-20 22:00:41

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