23 Jun
2009
23 Jun
'09
1:14 p.m.
From: lynchaj at yahoo.com
To: cctalk at classiccmp.org
Subject: RE:NEC uPD7220/GDC Design Manual
Date: Wed, 17 Jun 2009 21:37:04 -0400
--- On Wed, 6/10/09, Andrew Lynch wrote:
I have bought in the eigthies a eurocard sized board with memory and
the 7220 GDC (for a lot of money). So, it must be possible to build a
graphics module on 160x100 mm with the 7220, especially now that large
capacity RAM chips are available. I also found a schematic with the 7220
but I cannot say if that is the schematic of the module ...
The schematic is just 2 pages, so I can scan that and email it to you.
I have found the manual I remembered. It is called "?PD 7220 GDC GRAPHICS
DISPLAY CONTROLLER", and has 112 pages. It contains software sections and
hardware descriptions. In the back is a minimum GDC system design schematic.
I don't work at Oc? any longer, so I don't have the nice fast hi-res
scanning machines available to me anymore. I guess that it is possible to
scan the 112 pages, but I don't need the manual anymore. For snail mail
cost (from The Netherlands), I can send it to you. Contact me privately.
It would be nice if you could scan it and pass that on to Al for archiving
on bitsavers.
greetz,
- Henk.
From: Andrew Lynch
Subject: NEC uPD7220/GDC Design Manual
To: cctalk at classiccmp.org
Date: Wednesday, June 10, 2009, 8:45 PM
Hi! Does anyone have the NEC uPD7220/GDC Design Manual?
I am looking for one as part of research on building a home
brew NEC 7220 video board.
Thanks and have a nice day!
Andrew Lynch
I waited with a response, assuming that somebody has the manual
you are looking for. I am not 100% sure, but I might have that
manual. I am sure that I do have _a_ NEC 7220 GDC manual, and
I remember (15+ years ago) that I used that manual to write a
BASIC program to calculate register values based on the timing
parameters for the VDU. I don't remember if the manual contained
hardware info, it might. Next time I am in the old house, I will
search for the manual in the attic. Perhaps this weekend ...
- Henk.
-----REPLY-----
Hi Henk! Thanks! Any help you can provide is greatly appreciated. I am
interested and researching the possibility of a NEC uPD7220 home brew video
board. The SY6545 video board I made for the N8VEM project is working out
really well but it is just a simple character only display.
Ideally, you could scan the book if that is possible but if not would you be
interested in selling it? I contacted NEC and they didn't know anything
about it. Apparently very few people still have the manual and bitsavers
doesn't have it either. I did some library searches but no luck although it
is cited as a reference in a couple of college papers like masters thesis,
etc.
What I really need to know is if I can implement a simple circuit using few
enough 74LS TTL ICs to fit on a Eurocard ECB board. That means it can't be
more than about 30 maximum. Using high capacity SRAMs should help but I
think it requires some funky latching mechanisms to share the video address
and data lines.
I looked at the NEC APC video board and it is just huge. I hope that is not
an indication of the complexity needed!
Thanks and have a nice day!
Andrew Lynch