ADM-3A/HP 6144 Terminal Updates

From: Paul Williams <celigne_at_celigne.freeserve.co.uk>
Date: Thu Sep 19 12:46:01 2002

Loboyko Steve wrote:
>
> ADM-3A
>
> I read the upper and lower case chips, programmed a lower case
> 2716, and made a small adapter from to make the 2716 "look" like
> a 2513 in the socket, installed the chips/adapter, flipped a few
> switches, and voila!

Nice work Steve, and thanks for the PROM files.

A very trivial question: can you see any particular reason why the
glyphs in the lowercase ROM run backwards (apart from "address lines 3 -
8 are inverted"!) Does this make anything simpler? I've just found the
ADM-3 Maintenance Manual, and it appears to have the same configuration,
but it just says

"... the lower case ROM is a custom masked part. The one unusual thing
about this is that all of the address lines into the lower case
character generator are inverted."

No explanation! And it can't be all of the lines on the ADM-3a, because
the 8 scan lines run top to bottom, as with the upppercase ROM.

- Paul
Received on Thu Sep 19 2002 - 12:46:01 BST