25 Apr
2007
25 Apr
'07
8:52 p.m.
Subject: Re: Hand-rolling a CP/M machine
From: woodelf <bfranchuk at jetnet.ab.ca>
Date: Wed, 25 Apr 2007 13:24:17 -0600
To: General Discussion: On-Topic and Off-Topic Posts <cctalk at
classiccmp.org>
Well if anybody is doing VDM-1's the big problem is that you can't find
the Character ROM any more. I like the idea of TTL display like VDM-1
but since this is not the late 70's a 80x24 screen is reasonable
and the data out is a simple VGA format, since the monitors are easy to
come by.
You have to be kidding me. All you need is a 2764 and a programmer.
It's a ROM and the pattern is in the manual, what could be easier?
Actually if someone were building I'd suggest using a 2764 over the
part used on the VDM1 as that was a two or three voltage part and
27C64(or even a 27C256) is common as flies plus lower power.
Allison
You can
copy the screen logic for TRS80 as that is a basic 64x16 as well.
Good thing to
keep in mind.