28 Apr
2007
28 Apr
'07
4:18 a.m.
Hi,
My experience is that all the second processors -- no,
make that
all the 'cheese wedgrs' -- are rear.
It's a shame I never got one when I picked up my other "wedges". It was
always on my "list" of things to get, but they used to be reasonably easy to
find at radio rallies and I always ended up finding something more
interesting and leaving it for "next time".... :-(
I think you've forgotten the 'TUbe ULA'
That's a 40 pin custom chip
that handles the communication between the Beeb and the second....
I certainly had. Bit of a show stopper that really.... ;-)
<grin> I was just trying to remember where I'd stored that wirewrapping
stuff I haven't touched for 15 years too.</grin>
The Torch Z80 board did, indeed, use only sandard
chips.
Changing the subject slightly, IIRC the original "Acorn 6502 Second
Processor" cheese-wedge was just that, a faster 6502?
Did Acorn ever release a "cheese-wedge" 65c02 or 65816? Also, is it possible
to replace the 6502 in one of these with a 65c02; not that I'd actually try
it, unless the 6502 was socketed, but I recall having BIG problems (in fact,
total failure IIRC?) when I tried running a 65c02 in a Model B sometime in
the early 90's?
TTFN - Pete.
29 Apr
29 Apr
9:47 a.m.
New subject: Acorn Second Processors
On 28/04/2007 05:18, Ensor wrote:
Changing the subject slightly, IIRC the original
"Acorn 6502 Second
Processor" cheese-wedge was just that, a faster 6502?
Actualy, it's a 3MHz 65C02.
Did Acorn ever release a "cheese-wedge"
65c02 or 65816?
See above :-)
? Also, is it
possible to replace the 6502 in one of these with a 65c02; not that I'd
actually try it, unless the 6502 was socketed, but I recall having BIG
problems (in fact, total failure IIRC?) when I tried running a 65c02 in
a Model B sometime in the early 90's?
I can't think why -- it's a drop-in replacement and lots of people have
done it. Sometimes you need to change the 74LS245 data bus buffer
that's near the 6502 to get best results, but usually only if a Second
Processor unit is involved.
--
Pete Peter Turnbull
Network Manager
University of York
31 May
31 May
2:29 a.m.
New subject: Acorn Second Processors
Hi,
Ah, thanks for that....it's been a few years since I had the lid off mine.
I never did figure it out, it *should* have just worked....but didn't, the
machine wouldn't come out of reset.
It was a known good processor too, worked perfectly in the machine I
salvaged it from (a prototype system I had in my desk draw at work (we used
65c02s as second processors in our terminals to read barcodes, mag cards,
etc)) and also in an Atari 400. Wierd.
Changing the
subject slightly, IIRC the original "Acorn 6502
Second Processor" cheese-wedge was just that, a faster 6502?
Actualy, it's a 3MHz 65C02. ....problems
(in fact, total failure IIRC?) when I tried running
a 65c02 in a Model B sometime in the early 90's?
I can't think why -- it's a drop-in replacement and lots of people
have done it.... ....Sometimes you need to change the 74LS245 data bus
buffer that's
near the 6502 to get best results, but usually only if a Second
Processor unit is involved.
Hmmm....I'm not 100% certain, I had two Beebs then, but I don't think that
particular machine had a 2nd processor attached (my other Beeb had the Torch
Z80 2nd Processor and "Disk Pack").
I *DO* remember also being unable to get a Solidisk sideways RAM/ROM board
(and clock speed accellerator?) to work in that machine. In fact, the reason
I tried installing the 65c02 in it was bevause the Solidisk board was
supposed to support the use of a 65c02 at a faster clock speed - the board
plugged into the processor socket and the processor into the board.
Maybe it was an early revision main board in the Beeb?
TTFN - Pete.
4:10 a.m.
New subject: Acorn Second Processors
Ensor wrote:
Hi,
Ah, thanks for that....it's been a few years since I had the lid off mine.
>>....problems (in fact, total failure IIRC?) when I tried running
>>a 65c02 in a Model B sometime in the early 90's?
>
I too recently tried that, with three new 65c02's. The BBC would have
none of it : it only booted with the NMOS 6502
Jos
Changing
the subject slightly, IIRC the original "Acorn 6502
Second Processor" cheese-wedge was just that, a faster 6502?
Actualy, it's a 3MHz 65C02.
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classiccmp＠memory-alpha.org.uk -
jos.mar＠bluewin.ch -
pete＠dunnington.plus.com