Date : Fri, 07 Mar 2008 09:06:03 +0100
From : eelco@... (Eelco Huininga)
Subject: TUBE chip, accessing 'Parasite' side - 16Mhz 65C02S
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"
> mnemonics in assembler, e.g. PHX, PHY, STZ, etc. This is a no brainer and a
> 5 minute exercise. Without the solidisk board, the CPU will still be running
> at 2Mhz, but the availability of running 65Cxx code and BASIC4 is worth the
> upgrade. (including faster Foating Point variables AND half a significant
> digit more accurate, but still not IEEE754).
There are some drawbacks though. Programs which use illegal opcodes (Zalaga
for instance) won't run properly on a 65C02 processor, and some hardware (like
the Solidisk 128k SWR upgrade for the 32k SWR module) have problems with the
slightly different timings. Took me years to figure that last one out :-)
> But to make a project, I think the solidisk 4MEG was very interesting. It
> would be possible to build an 8 or 16Mhz host board using the 65C02S. The
> major difficulty would be EPROMS. All existing 1980s UV-EPROMS are too slow.
> So it would need an alternative solution to sideways ROM address space,
> perhaps modern PLCC EEPROMS similar to a modern PC BIOS chip.
I'd say: use a flash ROM so you can do live-programming.
>>> QUESTION 1: Does anyone have source code for BASIC4 or later? Note this
>>> Q is for assembler source, not a hex ROM dump.
http://acorn.huininga.nl/pub/docs/sourcecode/Acorn/BASIC%204.8/BASIC48.asm
Not commented unfortunately. I think there's a commented version lurking out
on the internet somewhere.
>>> QUESTION 2: Does anyone else have a solidisk 4MEG board, or data/spec
>>> for it?
...or schematics?
>>> QUESTION 3: Does anyone have source code for B32K OS1.20? Or Master
>>> OS3.20? Note this Q is for assembler source, not a hex ROM dump.
I've put the Master OS 3.20 disassembly it online at
http://acorn.huininga.nl/pub/docs/sourcecode/Acorn/OS%203.20/OS%20v3.20%20(Acorn%20BBC%20Master).asm
Not commented either. Maybe I'll get to that one day :-)
Cheers,
Eelco