On 11/15/2017 02:36 PM, smf wrote: >> Does this still apply to chips made after CSG/MOS went out of business? >> > Was anyone still second sourcing 6502 by then? I was under the > impression that everyone had switched to CMOS designs. > >> Also, I have doubts about the later 6502 still being NMOS. >> > It's possible. The 6xxx CSG/MOS chips are supposed to be NMOS, 7xxx > HMOS-I & 8xxx HMOS-II, but they have been known to lie (I think the > later 6526 were HMOS-II). They were... And starting at the end of 1986 on MOS/CSG chips you could see it from the number after the Datecode. If it starts with a '2' it's HMOS-II, if it starts with a '1', it's NMOS. Internally, the CIAs had the number '8521' on the die. The other numbers indicate the revision. > Conventiently that covers the c64/plus4/c128, so as long as the > undocumented opcodes are stable across all three then they are safe to > use no matter what process the chip was made with. Did someone ever test that? > I doubt MOS/CSG made a huge number of 6502's though, they normally had > better uses for their fab. Although they had time to produce the HMOS-II > 8501 in 1988 (maybe someone at MOS/CSG loved his plus4, but the CPU broke). I have 8501 with a datecodes from 1989 and 1990. Also, they did a new revision of the 8501 in 1986 since I have a '8501R4' with datecode '4986'. Also, I have a 1541-II with a CSG 6502AD with datecode 0791. Process and revision indicator is '1D'. So Commodore did make the 6502 for a long time in NMOS. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2017-11-15 15:00:03
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