11 Aug
1999
11 Aug
'99
12:01 a.m.
On Tue, 10 Aug 1999 21:15:37 +0100 (BST) Tony Duell
<ard(a)p850ug1.demon.co.uk> wrote:
The System 1 was 2 Eurocards. One of them contained a
6502, 8154 RAM/IO
(with an optional second one), 1K of RAM, and a monitor ROM. The other
contained a hex keypad, 7 segment display, and a cassette interface.
Together they formed a minimal 6502 development system.
This was the first computer I ever built (from a kit). It
was back at school, in about 1978, when I was electronics
lab technician. As you say, two Eurocards, one for
CPU/ROM/RAM and the other for the keyboard, display and (I
think) the cassette interface. The LED display was the
multiplexed type, as used in calculators of the time.
The System 2 was in a rack. It used the same boards as
the System 1,
although the keyboard/display were left off (the second board was just
the cassette interface). There was another card which contained a 40
column text-only VDU and one with more ROM/RAM on it. There was also a
full QWERTY keyboard which (IIRC) plugged into one of the 8154 ports on
the CPU board.
I have a rack-mounted Acorn System Three, which has the
disk, full keyboard, VDU and a power supply. I've also
got spares (like EPROMs) and a little documentation.
...
These machines are not that common, even in the UK, so
they're worth
saving if you ever see any. A few weeks back I spotted a totally bare
Eurocard in a local electronics shop. I believe it to be a sound card for
an Acorn System (although there are no markings on it at all...). One of
the puzzles for the next few months is to work out what all the
components should be (there is no silkscreen at all) and assemble it.
Are there any part numbers or markings? I can compare it
with my system, which certainly has an optocoupled parallel
I/O card, and may have a sound card.
-tony
--
John Honniball
Email: John.Honniball(a)uwe.ac.uk
University of the West of England