[Coco] FW: CoCo2 lower graphics
cocomalt at 6809.org.uk
Sun Jun 19 02:33:11 EDT 2016
"Michael Pittsley" wrote:
> I was unable to send this to the group due to the attachments being too
> large. Any additional assistance you could give would be greatful.
Hope you don't mind, I'll reply to the list, and have uploaded the
> I'm not really sure how to respond to these messages on here. I hope I have
> it right. Anyhow. Running screen0,1 goto 10 doesn't do much. From the TV
> I have the CoCo connected to, it presents an orange line that runs up and
> down the screen until I press break. Attached see the screen shots or what
> I am talking about the lower / bottom half the graphics not working.
So to me the Frogger shot looks like a low-res mode is being presented
as hi-res. The VDG itself doesn't do this, it's the SAM that handles
the addressing, so if possible I'd try replacing that chip (6883,
SN74LS783/5) - everything else the SAM does looks like it's working
so I'd guess at some internal fault just limited to the video address
counters or divisor selection.
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