Re: PET video to VGA

From: Rob Clarke <>
Date: Thu, 19 Dec 2013 17:53:09 +0100
Message-ID: <>
Here's my spreadsheet with all the timings from all common ROM's I could 
find plus the others that are on zimmers. You can use this to twiddle 
with the values and see the effect on the frequencies.

Anders is correct for the 80 column edit roms. For the 40 column ROM's 
the registers are at E7B1 and E7C3.


On 19/12/2013 13:21, Anders Carlsson wrote:
> Hervé wrote:
>> - What are registers values supposed to be OK ?
> Perhaps André:s site can help you?
> It seems to that changing the register R2 would move the image to 
> either left or right. The second page has actual register values, see 
> the ones for CS/A65 as those were tuned for a 50 Hz TV. André also has 
> links to the composite video adapters and mentions that the CRTC 
> values need to be changed in order to get them to work.
>> - Locations, in this hacked ROM, to patch to change those registers 
>> values ?
> A quick hunt with the xpet monitor suggests $E72A (lower case?) and 
> $E73C (upper case/graphics?), but I'm not entirely sure.
> Best regards
> Anders Carlsson
>       Message was sent through the cbm-hackers mailing list

       Message was sent through the cbm-hackers mailing list
Received on 2013-12-19 17:00:05

Archive generated by hypermail 2.2.0.