On Thursday 05 March 2015, 19:30:31 Gerrit Heitsch <gerrit@laosinh.s.bawue.de> wrote: > On 03/04/2015 11:09 PM, groepaz@gmx.net wrote: > > however, 6526A are selected regular 6526 that just happen to work at 2mhz, > > its exactly the same die as regular 6526 (or 8521 for that matter). there > > are 6526 labelled chips with 8521 die in them (shows the timer irq > > difference) and there are 6526A with the regular 6526 die in them (does > > not show the timer irq difference). thats why we changed it into "6526 > > (old)" vs "6526 (new)" in VICE, using the "A" suffix to indicate this > > difference is not only formally wrong (it means "2 mhz") but also does > > not (always) work in practise. > What added to the confusion was that most (if not all) HMOS-II CIAs were > able to run at 2 MHz and therefore were stamped '6526A' or even '6526B'. > I have yet to see a 6526 in HMOS-II without the 'A' or 'B'. Sometimes it > was stamped on the chip later and is therefore not fully aligned with > the numbers, but it's there. The NMOS 6526 were mostly 1 MHz types with > no additional letter. > > So it's easy to see how the thing about 6526 and 6526A started. one of my C64s had a 6526(not A or B) with "new" behaviour - that was what made me investigating this issue some more back then (until then, i only saw 6526A with that behaviour myself as well) :) -- http://www.hitmen-console.org http://magicdisk.untergrund.net http://www.pokefinder.org http://ar.pokefinder.org Es geht nicht darum, dass wir zu einem Überwachungsstaat werden, sondern lediglich darum, zu speichern, wer wann mit wem und wo telefoniert hat. <Mechthild Ross-Luttmann, CDU> Message was sent through the cbm-hackers mailing listReceived on 2015-03-05 23:00:05
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