A quickie
Charlie
boards are going for on fleaBay ATM..?
Good news for the sellers but not for me - I want to buy one so I can
then get my hands on one of JK's lovely 'super' co-pro boards for my
Master. But I can't justify the price just to get my hands on one of
Ferranti's ULA's.
Now I have a plan:
I knew about PMS's el-cheapo (relatively) Tube Co-Pro for which I can
find very little info, but I didn't know about this...
http://www.acornelectron.co.uk/hardware/cats/pms.html
He, he. A 2nd 6502 to for the Electron to go in the cartridge slot of
the PLUS 1, the same slot (unless I'm very much mistaken) that one can
find in any Master.
Ho, ho. The plans + software are available for this, as are the parts
according to Google. I feel another project coming on.
Now the questions are:
-Can anyone see a reason why this wouldn't work with a Master?
(never mind about the point - this is retro-hobby land)
-It would be nice to do an update rather than a direct re-run. The
primary goal being to use higher capacity DRAMs to reduce the chip-
count. Does anyone know of any easily available and suitable 64/32K
IC's?
-It would also be nice to use a (faster) 65c12 rather than a 2Mhz
6502A. Or am I letting myself in for a world of Hertz..?
(slight pun)
Oh, and:
-Do I ever actually complete any of my projects?
Well, some of them.
Thanks all,
Charles.
Theo Markettos
> Ho, ho. The plans + software are available for this, as are the parts
> according to Google. I feel another project coming on.
Take cover! ;-)
> Now the questions are:
> -Can anyone see a reason why this wouldn't work with a Master?
> (never mind about the point - this is retro-hobby land)
Electrons were clocked at 1MHz, weren't they? There might be timing issues.
Otherwise I can't think of anything, but 8-bit stuff isn't my forte.
> -It would be nice to do an update rather than a direct re-run. The
> primary goal being to use higher capacity DRAMs to reduce the chip-
> count. Does anyone know of any easily available and suitable 64/32K
> IC's?
Something like a 44256 would do (64K x 4, I think). Though I last paid
attention to the availability of these chips in about 1991 when they were in
the Maplin catalogue. But it might be easier these days just to use static
RAM - why have extra refresh logic when you don't need it?
> -It would also be nice to use a (faster) 65c12 rather than a 2Mhz
> 6502A. Or am I letting myself in for a world of Hertz..?
Well, Western Design Center will sell you a 14MHz W65C02S these days, if you
want one... ($7 each plus rather a lot for post)
Another option is to implement the whole thing, 6502 and all, in an FPGA.
That would solve Tube ULA sourcing problems. Or do what Sprow has done, and
implement everything in FPGA except the 6502.
Theo
(who notes that this appears to be the first non-PC card thread in this
group for over 10 years :)
Charlie
> Theo
> (who notes that this appears to be the first non-PC card thread in this
> group for over 10 years :)
Thanks yet again Theo.
First non-PC thread in 10 years, eh?
I shall have to be even more controversial in future. ;-)
Charlie
Hello,
Just to let any who may have kept an eye on this thread I bought a
ReCo6502 + ReTuLa (tube ULA replacement) from John Kortink...
...and excellent it is too!
So for the mo' I've given up on the idea above though I still think
with a fast CPU and modern memory it would still make an worthwhile
project.