27 Mar
2005
27 Mar
'05
12:17 a.m.
Hi,
river said:
Hi,
I've got a few old SC/MP-II chips and I decided to try and do something with them.
It appears that only 2 of the chips actually work, but I've just proto-typed a small
system with 4K ROM, 4K RAM, an 8251 USART and an 8255 PPI. I got the
comms going yesterday and the PPI is fine. Excellent old vintage stuff.
Excellent! I've a soft spot for the old SC/MP, and I still have my old
Science of Cambridge (Sinclair) Mk14, which still works. Before that
I had a home-brew system based on a board produced by a local firm here.
This was about 1976/7
I forgot how cumbersome the SC/MP instruction set was, but it's fun trying
to
code around its deficiencies. I've got a listing of the original KITBUG for
the
SC/MP, but I'm going to expand on it to provide more functionality. I'll
try and
base the monitor off the old Intel 8080 SBC monitor.
The instruction set has an elegant simplicity :-)
It makes position independent code easy though, and I wrote an operating
system for the Mk14 that allowed me to load numbered programs from tape,
with auto-run if required, multiple resident programs (in 1K ram!), and
would recover the memory vacated by deleted programs. Good fun...
I did start to write an emulator, the basics of which I prototyped
and it works, but other projects got in the way. Not sure where the
code is now.
--
Cheers,
Stan Barr stanb at dial.pipex.com
The future was never like this!