Sigma Electronics Systems Display Generator 5564
ard at p850ug1.demon.co.uk
Fri Mar 6 00:07:10 CST 2015
> Cool find!
I think I rescued it about 25 years ago, as it looked interesting. It then got somewhat hidden in my old house and
has turned up in the move. Fortuantely  my new house is mine alone so I can put classic computers everywhere
 Don't take that the wrong way. I wish my parents were still alive, I think of them every day. But living in
their house meant I had to (very reasonably) go with their rules.
> One of the full-width cards is something like 'area fill'. So it does that in hardware too?
> Yes, probably, it is not that big trick (in theory). Example Amiga's custom chipsets was capable for area fill (line
> mode), and btw, prototype of that custom chip set was made from TTL chips:http://www.floodgap.com/retrobits
Sure. My guess is that the line drawing on this terminal is going to be similar to that on the HP2623. A simple
state machine where the main CPU (in the HP a Z80, in the Sigma a 6800) calculates various parameters and
the state machine goes along setting pixels. The area fill board is perhaps 50 or so TTL ICs. Not complex
really. But I think it is a high-end feature for a 1970s terminal.
> Please send some photos of that Sigma's miracle!
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