Eddie's Micro page.
Some recent micro projects can be found on my projects page
MINI-SCAMP - 1978
I built this Mini-Scamp
microcomputer in 1976 (I think). It was a Dick Smith Electronics
(DSE) kit from the days when Dick Smith actually owned and ran
Dick Smith electronics. The design was published in "Electronics
Australia" (EA). It was based on the SC/MP CPU from National
Semiconductors. It boasted a massive 256 bytes of RAM (yes Bytes
not Kbytes) - this was 4 times more than the earlier model. It
had no ROM or EEPROM of any kind. The complete user inferface is
visible in the photo above. Binary code was entered into the RAM
by dialing up the data byte and address in binary using toggle
switches. Pressing the deposit button stored the byte in memory.
The LEDs showed the current contents of the memory location.
After the program was enter in this manner one of the switches on
the right was flipped from DMA to run mode and the micro executed
the code (the other switch was power). The micro could display
bytes on the LEDs and read bytes from the data switches - the
request LED was there to signal the user to enter a byte and
press deposit. No problem with Y2K bugs, viruses or hackers
The 2650 - 1979
After the SCMP came the sygnetics 2650. I stayed with this
processor for many years and many generations of hardware. My
first 2650 was another kit probably EA and DSE as above. From
memory it had up to 7K of RAM and 1 K of rom. It ran from a 110
baud serial key board, talked to a 110 baud serial video terminal
unit (VDU) and could load and save programs onto a cassette again
at 110 baud. Compared to the SCMP this was heaven. The
keyboard VDU and cassette were all kit built and I used a large
valve TV for the display.
Double density, 8 and 5 inch floppy
disk controller with EPROM programmer and real time clock. -
I had you do some major work on the DOS to get it to work
with this card. The CPU only ran at 1 megaherz and wasn't fast
enough to pole the controller as it did previously this was
because of the higher transfer rates for double density and/or 8
inch drives. There were other problems as well while formating
the longer tracks.
One of the programs I wrote when I first got a VDU that could do crude graphics was a game I called UFO - very crude - it was around 1979. Anyhow I got this email a few months back...
Reply-To: "Andrew Davie"
"...every few seconds a UFO will traverse the screen, on the base line is drawn the lid of a missile silo" I have a listing in front of me, circa 1979 and written by E.Matejowsky. I'm figuring thats you, and thought you'd get a kick out of learning someone nearly 20 years later is casually browsing through the listing. Cheers A
I'm a collector of old computers - anything homebrew or early home and game computers (not IBM!!) and this is one of the ways I build up contacts and track down old machines, programs and documentation. This listing was saved from the dumpster some number of years ago by an electronics guy, and when he decided to sell his old computer (to me!!), I asked if there was anything of this sort he would like to send to a good home. Having found the listing I thought it would be both fun and possibly productive attempting to find the original authors of some of these programs. I'm persistant like that ;) So, a few net searches (just a couple of minutes actually - I wish I could make it sound more sherlock-holmesish but it was simple) and I found you :)
Of course, your name wasn't that hard to track down - but I've also found some of the other authors of these programs, too. The reactions have been fun, including "well bugger me dead!!"
Until 1982 virtually all the programming I did was in
assembler. I got interested in a language called FORTH after
spending some time on Great Keppel Island with Peter Milford and
his friends who were forth fanatics. Later I was given a FORTH
compiler for the 2650 by a friend -the late Dr Dan Hamilton and
slowly got to understand this odd language. Around this time I
resigned from my job in the photographic industry and tried to
make a living amongst other things by fixed video games,
unfortunately I didn't see the money for much of what I did and
needed to find something else.
My time at
UQ – 1984-1992
Home Office- 2003 ????
Great Microprocessors of the Past and Present
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