21 Oct
2005
21 Oct
'05
7:28 p.m.
Subject: Character Generator ROM data
From: Chuck Swiger <cswiger at widomaker.com>
Date: Fri, 21 Oct 2005 21:47:44 -0400
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
Gang -
Anybody know of readily available data for, say, 7x9 dot-matrix characters?
I'm looking for a downloadable rom image for something like in old video
cards to
paint ascii characters on a display.
For example, my Polymorphic Systems Video Terminal Interface (VTI) card uses
an MCM6571A (or it could use a 6574) -BUT- I do not need exactly that
font - any 7x9 data will work. Spent the past hour trying terms in
google w/o
anything usable turning up.
Is simple. Find a pattern you like in row or colum scan and convert the
bit pattern to a string of hex values and cook an Eprom/EEPROM.
Myself I needed a while back a 7x9 that had decenders one of the M6571
series has that so I found that data sheet. They fit easily into a 2716
or similar.
Hint where they go in rom is based on SxC IE: number of scan lines typically
11 or 12 for 7x9 fonts and the number of characters. For 7x9 CRT fonts
(ROW scanned) the low 4 addresses lines are the row data and the next 7
(128 char font) are the character address. Nothing magic.
Allison