On 11/19/2011 11:05 PM, Segher Boessenkool wrote: > >> Another way I have been thinking about is to rig up a +12V regulator >> and use a 6569R5 in a board made for the 8565R2 and supply pin 13 with >> +12V. Shouldn't be too hard, the voltage doubler circuit is still >> there, just needs a 7812 plus some capacitors. If we still don't see >> grey dots then, this suggests it's something with the 856x-VIC. > > Before doing such major surgery, That's not really major surgery, it would be fully reversible and mean only one bent pin (13) on the 6569R5 and some open wiring. I have a demo that will produce the grey dots reliably. > maybe we should get some more data first: > get scope traces of all the relevant signals (clock, VIC #CS, R/#W, #AEC, > #RAS, #CAS, some A and D pins) on various different machines. I couldn't > find a single bus trace online. I can see if I can get around to do some of those. Which signal in relation to what interests you most? I don't have a logic analyzer, just a digital scope though. >> I could, but the C64C I have access to at the moment (the others are >> stored away) doesn't show the vertical bars. Most C64C only show them >> somewhat, they are really visible on a C128 though. > > None of my C64C do (and no dots either!) There is a problem with using the term C64C. I own one that says that on the bottom, but still contains a 250466 board, that means 65xx-parts and 82S100 PLA. It's better to use the board part numbers. The board with the large PLA is the 250469. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2011-11-19 23:00:19
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