Re: Re: Re: PET video to VGA

Date: Thu, 19 Dec 2013 12:31:35 +0100 (CET)
Message-ID: <1563459840.49729.1387452695012.JavaMail.www@wsfrf1321>
I had a try, yesterday evening with this hacked ROM. Results, even if still imperfect, are usable and are the best ones I could have until now. In détails :


[Note : no shielded cables in my test]

(Analogic) SCART/Composite video with "normal" 6540ROM adapter : Had a stable B&W display, really too much shifted to the upper left, with something as big snow. Not really usable. [and somewhat out of what I wish, a VGA display, not a TV display]

(pure digital) VGA/GB8220/Direct 7402 pin 4 output on 6540ROM adapter : Had a "mostly stable" green display, shifted to the right but I can manage changing GB8220 setup. In "mostly", I mean GB8220 seems to loose sync once every 5 second but recover very fast. While this is not the ideal setting, this is suficient to allow me to peek & poke to 6545 registers, trying to find the right values. I'm comparing PET's video output with C128's RGBI output as a reference.

Keyboard maps to QWERTY but that's okay.

... Could not obtain anything with SCART using Steve's editor ROM ... "No signal" !

Does anyone knows :
- What are registers values supposed to be OK ?
- Locations, in this hacked ROM, to patch to change those registers values ?


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Message du : 18/12/2013 18:08
De : "Rob Clarke " <>
A :
Copie à : 
Sujet : Re: Re: PET video to VGA

If it helps you, one of the edit ROM's Zimmers already has the CRTC 
already set for 15.625 khz horizontal. I know this is PAL timing but 
possibly a step in the right direction.

That one is:

cheers, Rob

On 18/12/2013 17:36, Steve Gray wrote:
> I'm in the middle of working on my editrom project, but hopefully I
> could build whatever combination of screen, timing and keyboard you
> need. Are you using a French keyboard or standard B? I haven't looked
> at the French edit rom binaries yet.
> I have other edit rom request to fill as well... so little time.
> Steve
> FROM: "" 
> TO:
> SENT: Wednesday, December 18, 2013 11:13:22 AM
> SUBJECT: Re: Re: PET video to VGA
> Anders,
> I had forgotten to try this ... Direct 6540ROM to Scart using Steve's
> editor ... Not the ideal solution in my mind but simplier ...
> Thanks
> Tous vos emails en 1 clic avec l'application SFR Mail sur iPhone et
> Android - En savoir plus [1].
> ========================================
> Message du : 18/12/2013 17:01
> De : "Anders Carlsson " 
> A :
> Copie à :
> Sujet : Re: PET video to VGA
> Steve Gray wrote:
>> Ok, so if you have the right NTSC signal you will need to adapt the
> rest
>> of the stuff to work on VGA.
> If Hervé uses his LCD TV with SCART input, he probably can stop at
> this
> point as just about every (?) European TV set will accept NTSC
> composite
> video, at least in monochrome. Since the PET in default form doesn't
> output
> any colours anyway, going through conversion to RGB or VGA would be
> plain
> overkill unless considered an exercise. Probably the GB8220 converter
> could
> be used as a scan doubler if the desire still is to get a 31 kHz
> signal.
> Best regards
> Anders Carlsson
> Message was sent through the cbm-hackers mailing list
> Links:
> ------
> [1]

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Received on 2013-12-19 13:00:06

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