[BBC-Micro] TUBE chip, accessing 'Parasite' side - 16Mhz 65C02S
fragula at hyperdark.org
Fri Mar 7 12:32:27 GMT 2008
David Warrington wrote:
> I think ANYONE still using a beeb today should just "drop in a 65C02" or
> "65C02S" into their beeb to allow them to use BASIC4 and the "65Cxx"
Gaahh It didn't work for me.. I had a few, probably fairly well stacked
with hardware, model Bs, and the 'C02 (Literally CMOS, a 65C02P 2MHz)
outputs didn't drive hard enough. The machine would boot sometimes if it
felt like it, but was sure to crash within a few mins. Buffering of the
address and data lines would be needed to make it happy. So not all
65C02s will work.
Also somebody back then (oh the 90s for sure!) recalled that one or two
of the clock and/or control signals behave or are timed slightly
differently from the 6502A. It was all a little too marginal even for me
(i;.e. me wot thinks flying wires - all matching red - around is more
fun than using tracks on PCBs, and counters make nice latches, coffee is
fine for liquid cooling the 8271 etc.) It may have worked on a bare and
unexpanded, but it would have been fairly marginal, and crash prone.
But that was with the a literal 65C02, i.e. 65C02P/65C02P2, (Rockwell
IIRC) I had some others which might have been WS65C02, which were what I
tried. There may be other 65C02 variants with "better" (i.e. bipolar/TP)
outputs etc. would help, that work just fine, and if so I wouldn't mind
one or two of them, or even a full part # so I can go dig for some.
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