RE: commdore screen text / graphic mode

From: Martin Hoffmann-Vetter <martinHV_at_arcor.de>
Date: Fri, 16 Nov 2012 00:27:21 +0100
Message-ID: <002b01cdc388$c373b0c0$6800a8c0@mhv.webmade.com>
Hello,

> I looked at all the edit roms on
> zimmers and put all the CRTC initialisation registers into a s/sheet.
> You can get it here:
> 
> http://inchocks.co.uk/commodore/PET/PET_CRTC.xls

That's a nice work.

> As Martin said, it's usually 2
> except for one alternate version of the 901474-04 rom which had only 1
> extra scan line.

That's a special version. I can find 3 versions of 901474-04. If i look into your table, i would say the edit-4-80-b-50hz.901474-04-3681.bin is the original version. You find this version as 901474-04-0384.bin too.

At http://www.zimmers.net/anonftp/pub/cbm/demodisks/pet/8296d_diagnostic_instr.pdf.gz you find your 901474-04. But it's a 901474-04 with changed values and the new cbm number is 324243-02. But i've only see a 324243-02B and this CRTC values are the same as 324243-03 and 324243-04.

The last version is that one (and only) with 9 scanlines in text mode. This reduce the totaly lines from 400 to 313. Why? It look's like a PAL version. So this standard use 625 lines in 2 frames via interlace. I don't know any 40xx, 80xx oder 8296 with a PAL monitor. So i think it's a patched version.

My updated list is at http://mhv.bplaced.de/cbmroms/Commodore%20CRTC%20Einstellungen%2040xx,%2080xx,%208x96,%206x0%20und%207x0.xls.

Martin



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