Re: PET / cbm2 timing questions...

From: Ethan Dicks <>
Date: Mon, 20 Dec 2010 16:16:03 -0500
Message-ID: <>
On Mon, Dec 20, 2010 at 4:11 PM, "André Fachat" <> wrote:
>> Given that the system tick is *not* generated from mains...
>> but the VLSI chips still
> If you count the CRTC as a "VLSI" chip ;-)

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.

> The PIA 6520 does not have a timer. But in the PET the jiffy interrupt is
> created by the CB1 interrupt of PIA1 - might be a cycle or a few off 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?


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Received on 2010-12-20 22:00:31

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