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. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2015-03-05 19:00:55
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