Re: VIC 26 Lines Bug - Truth or Legend ?

From: Andre Kaesmacher (
Date: 2001-08-20 21:17:43

Martijn van Buul schrieb:
> wrote:
> > Just about this demo :
> >
> > Ninja (the coder of the demo) was ofcourse JOKING in that demo...
> ofcourse?
> > ofcourse the VIC doesn't overheat.. mostly becoz it is hardwired,
> > meaning that is fetches a byte *anyway* wether it has to or not.
> Eh? The VIC doesn't fetch very much character data in the border,
> if you ask me. Never heard of badlines in the border.

It's not really in the border, the badline access is still in the
displayable Area. 
For detailed Memory Fetching of the VIC2, read the Article from
Christian Bauer.
> > So displaying more gfx doesn't require more memory-fetches.  Also it would be
> > nonsense to think that displaying 26 instead of 25 lines (just 4% more) could
> > possibly heat up the chip =)
> It's not those 4% extra fetches that might be the issue, it's the way the
> VIC is fooled into doing them. One thing *is* clear, and that's that this
> effect isn't very stable. Often, it just crashes, because the memory isn't
> refreshed as it should anymore. The VIC is totally confused, and it might
> very well generate an internal bus conflict because of that. The VIC's
> innards are a bit clouded, there's no way to tell.

My Tests on the C128, and some C64s did not show the Feature that the
gets confused.

On what C64s does that happen ?

BTW, does the CPU get hotter, when it CRAshes ($02) ? 

Andre Kaesmacher
Take a look at http://WWW.ONLINEKUNST.DE
4502@3.58 MHz, 128KB,Blitter, Stereo 6581, 1280x400
256/4096 Colors, CBM Basic 10.0 !http://www.C65.ORG

       Message was sent through the cbm-hackers mailing list

Archive generated by hypermail 2.1.1.