Den Sun, 10 Jun 2018 15:50:50 -0500 skrev Segher Boessenkool <segher@kernel.crashing.org>: > On Sun, Jun 10, 2018 at 10:17:17PM +0200, Gerrit Heitsch wrote: > > On 06/10/2018 09:46 PM, Segher Boessenkool wrote: > > >On Sun, Jun 10, 2018 at 06:42:02PM +0200, Gerrit Heitsch wrote: > > >>On 06/10/2018 05:36 PM, Segher Boessenkool wrote: > > >>>http://siliconpr0n.org/map/mos/6526/mz_mit20x/ > > >>> > > >>>The ports are the low half of the pins (PA on the left, PB on > > >>>the right). > > >>> > > >>>(I have a .xcf if anyone is interested, marked quite a few > > >>>signals, but I haven't done the port stuff very much. It's > > >>>about 400MB). > > >> > > >>That looks quite different from the one I posted. Looks like MOS > > >>did quite a bit of redesign between the NMOS 6526 and the HMOS > > >>8521 (which still got labeled 6526). Might explain the little > > >>differences in the way they behave. > > > > > >No, this is an actual 6526r4. This is an 8521r1: > > > > > >http://oms.wmhost.com/misc/MOS_6526A_CIA.jpg > > > > > >(and this is an 8520r4, the CIA used in amigas; it has a different > > >TOD clock, and as you can see it's different from 8521 in other > > >ways, too. But clearly 8520 and 8521 are more related. The > > >lineage is almost certainly 6526 -> 8520 -> 8521: > > > > > >http://siliconpr0n.org/map/mos/8520/mz_mit20x/ ). > > > > Yes, but the 8521 is a drop in replacement for the 6526 (I have a > > C64 Board with a 8521R0 on U2) and later revisions of that chip > > have been labeled as '6526' again, probably to avoid confusing the > > customers. You can tell them apart by the datecode or by the '206A' > > or '216A' next to the datecode. > > _Almost_ drop-in replacement, yes. But the die photos are really easy > to tell apart (an 8521 does not say "6526" on the die, it says > "8521"). I can't remember which versions, but at least some version of the CIAs can only be used as one of the two CIA's in a C64. Using it as the other CIA causes keyboard problems. And when using it as the CIA that generally works causes interrupt failure in the common diagnostic cart (the one that's not called dead test, not sure if it has a better name than diagnostic). I guess it has cmos drivers instead of nmos drivers on it's output stage, and that causes problems with the keyboard when pressing more than one key at a time. -- (\_/) Copy the bunny to your mails to help (O.o) him achieve world domination. (> <) Come join the dark side. /_|_\ We have cookies.Received on 2018-06-12 18:02:09
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