Back in the 80s I constructed a "computer brain" in kit form, to
control the key matrix of a synthesizer keyboard, also in kit form.
It was capable of some neat tricks at the time, like programmable
arpeggiation, set chords, MIDI transforms, etc. It had a 1K memory,
as I recall, and a number keypad made up of actual metal pads painted
over. You programmed machine code into it, nothing higher, pressing
into the pads with your finger; I had to hold a cold water pipe with
my other hand in the Wintertime to make it recognize my touch.
Entering the machine code letters one at a time from pages and pages
of it printed in Polyphony magazine absorbed much of my waking
hours... -- Rich WB2GXM
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On 5/9/18, ajparent1/KB1GMX <kb1gmx@...> wrote:
COSMAC ELF,? Built mine back '76.
12 switches, 1 push button, 2 hex digits of led, 256bytes of ram and the
1802, 8 pieces of CMOS logic.
I still pull it out to play.? Runs well on a battery of 8V or more.
Also National SC/MP (both I and II), Texas Inst 9900 in the form of the
Technico starter board, 6800D1,
Kim1, TK80, Intersil 6100 Sampler (base PDP-8 in cmos), IMSAI IMP48
(intel8035), Intel SDK85 and
then memory fails me. There is a 6809 in there too.
My favorite is a 16 bitter made from TTL...? I decided I needed to
understand how computers
worked at?the gate level. So design and build.? Not very fancy but proved I
understood.? Killed
me wirewraping it too. The hard part was getting the carry logic right.? It
was sorta PDP-8 /nova
in its origins.?Also proved that once you have a machine... programming
happens, mostly by
need as it was unique.
Allison
