Hi! There is an ECB version of the uPD7220 GDC graphics board. It is not PC compatible at all but has "accelerated" graphics primitives. The NEC uPD7220 was from the same vintage as the MC6845 but much more advanced. Conversion from ECB to S-100 would be relatively simple and the design is already proven.
If anyone is interested in the ECB uPD7220 please contact me since I have a bunch of the "production" PCBs ready to go. It has 4 color planes (16 color with RAMDAC) and is VGA monitor compatible (640x480 and 800x600).
Thanks and have a nice day!
Andrew Lynch
--- On Sun, 7/17/11, norwe...@aol.com <nor...@aol.com> wrote:
From: norwe...@aol.com <nor...@aol.com>
Subject: Re: [N8VEM-S100:353] S-100 Vido board with 6845
To: n8vem...@googlegroups.com
Date: Sunday, July 17, 2011, 3:47 PM
Hi John,
Interesting! The 800 lb. gorilla in the room that everybody *tries* to ignore seems to be S100 video (80x24 or 25, that is).
Perhaps there is another option besides the 6845? Intel came out with a similar controller about the same time as Motorola introduced the 6845 - the i8275. It has similar capabilities, I think. There was a fellow (in Illinois, I believe) who sold a S-100 card, based on the i8275, back in the mid-80's. The big(?) selling point was that it produced VGA video (at a time when the whole microcumputer world was moving toward IBM and MS-Doze). I think I have one here somewhere, and maybe even a schematic and documentation? Might take me a while to find it, however (*grin*). I have NO idea about the availability of the i8275
anymore. It was a 40-pin DIP.
As far as the 6845 goes, the only video circuit I ever saw was one published in "Byte", in the Ciarcia column? Am I dreaming this? Anybody else confirm? Considering the source, it was most certainly NOT S-100. *shrug* Oh, and maybe there was another that came out in the "CRT Controller Handbook"? Again, probably NOT S-100. I'll have to look.
Love to hear peoples' thoughts about S-100 video.
Roger
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