26 Mar
2005
26 Mar
'05
7:26 p.m.
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.
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.
When she's all done then I'll wire-wrap it onto a single board and put it in a
nice display box. I like these things to work, as opposed to collecting chips
to sit and gather dust.
This brings me to a question. Does anyone know any chip brokers that sell
a small number of chips to hobbyists? I've tried a few but they seem uninterested
in selling small numbers and to private buyers. I don't understand this 'cos I
doubt
there will be orders for thousands of old chips like the SC/MP from businesses -
and rather then sit and collect dust at least the brokers could sell some of their stock
to private buyers.
river
27 Mar
27 Mar
3:17 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!
4:14 a.m.
On Sun, 27 Mar 2005 10:26:02 +1000, river <river at zip.com.au> wrote:
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.
Nice... I don't have any SC/MP chips, but I do have some INS8073s,
which should be an SC/MP chip, but with Tiny Basic in ROM. I have a
3"x5" vintage SBC with one, and a few loose chips. My board is an
MC-1N, for which I did eventually track down a copy of the manual last
year from the original vendor. I have permission to distribute it
from the copyright holder, even! Unfortunately, the
MC-1N seems to be
an obscure board... the rev I have is unusual now (there were
later
versions of the board with the same sort of I/O, but with a different
microprocessor).
For the record, the MC-1N has a 2K SRAM (6116), a clock/calendar chip,
a ROM socket, and an 8255 with all 3 ports brought out the front.
It's a nice little system that is just enough over minimal to be kinda
fun. Unfortuately, the 74S188 memory decode PROM doesn't allow for
more than 4 banks of 2K of SRAM. I _think_ a 16V8 GAL will work
there, if I lift the pullups (the 74S188 is O.C.) I don't have any
blank 74S188s, or I'd just blow one with a truth table that decodes
the max amount of RAM on a single select so it'd be trivial to use a
62256 (32K x 8)
I did get mine fired up with a terminal last year, and entered a few
BASIC programs to give it a whirl... It'd be possible to do a Star
Trek game on it (with more RAM), but I don't know if the BASIC could
handle a text adventure (most Tiny BASICs aren't excellent at string
maniupulation).
-ethan
5:03 a.m.
Ethan wrote:
Nice... I don't have any SC/MP chips, but I do
have some INS8073s,
which should be an SC/MP chip, but with Tiny Basic in ROM.
The INS8070 is essentially a SC/MP III, though National didn't call
it that. IIRC, it's not quite compatible with the SC/MP II (INS8060).
The INS8073 is the version of the INS8070 with 2.5K "NIBL BASIC" in ROM.
Eric
6:50 a.m.
New subject: show segment comming on in minutes
heard 2nd hand...
Currently on History Channel's Lost and Found program, US Eastern timezone,
next story after Jumbo the Elephant... ENIACish story. FX: searching for
vcr remote.
;)
- Mike
11:09 a.m.
On Sun, 27 Mar 2005 02:03:27 -0800 (PST), Eric Smith <eric at brouhaha.com> wrote:
Ethan wrote:
Ah... thanks for the extra detail... didn't realize there were
multiple versions of the SC/MP.
-ethan
Nice... I don't have any SC/MP chips, but I
do have some INS8073s,
which should be an SC/MP chip, but with Tiny Basic in ROM.
The INS8070 is essentially a SC/MP III, though National didn't call
it that. IIRC, it's not quite compatible with the SC/MP II (INS8060).
The INS8073 is the version of the INS8070 with 2.5K "NIBL BASIC" in ROM.
2:51 p.m.
I wrote:
> The INS8070 is essentially a SC/MP III, though
National didn't call
> it that. IIRC, it's not quite compatible with the SC/MP II (INS8060).
> The INS8073 is the version of the INS8070 with 2.5K "NIBL BASIC" in ROM.
Ethan wrote:
Ah... thanks for the extra detail... didn't
realize there were
multiple versions of the SC/MP.
In the interest of completeness, then, I'll note that the part number of
the original SC/MP was "ISP-8A/500". The SC/MP II was known as both
"ISP-8A/600" and "INS8060"; AFAIK it started as the former and was
changed to the latter, perhaps because they decided that having
punctuation in part numbers wasn't such a hot idea.
Similarly, the National Semiconductor PACE ("Processing And Control
Element", the world's first single-chip 16-bit microprocessor, PMOS,
1974) had the part number "IPC-16A/500", but the later NMOS version
is the "INS8900".
Eric
7052
days inactive
7052
days old
6 comments
5 participants
participants (5)
-
dogas＠bellsouth.net -
eric＠brouhaha.com -
ethan.dicks＠gmail.com -
river＠zip.com.au -
stanb＠dial.pipex.com