On 08/25/2011 06:54 PM, Segher Boessenkool wrote: >> Hm, I own a 6569R3, some 6569R5 and some 8565R2. I don't notice any >> difference in picture quality between the 6569-Revisions, the 8565R2 >> seems to provide a slighty brighter picture. It also has the >> 'grey-dots-bug'. If you write to the background or border color >> register (even if this doesn't change the contents) you get a grey dot >> on the screen at the moment the register is written to. The intro for >> Giana Sisters does show that quite nicely. Looks like a kind of 'snow >> effect' if done right. This doesn't happen on a 6569. On some >> 8565-VICs it goes away once the chip warms up. >> >> The bug is also present with TED and the VIC used in the C128. It >> seems as if it got introduced with the switch to HMOS. > > Are you sure this depends on the chip, and not on the board? The grey > dots are caused because #CS is active before the data lines are. The > dots go away if you add a cap to the #CS line. Well, TED doesn't have a _CS line, it does all decoding internally... Of course when it comes to the 8565, it could be that the 64pin PLA is a lot faster than the 28pin from the old boards and that's the cause. Can't easily use a 6569 in a new board though since the chip needs +12V. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2011-08-25 18:00:23
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