How do you make a distinction between your notion of VGA and EGA, which is much simpler, if you don't intend to support the higher horizontal rate and color depth? EGA was 16-shades of R, G, and B. VGA allowed for 64, with 6-bit shades of each of the three colors.

BTW, Robert Suding's name had only one 'd'. He was my boss during my last stint at Martin-Marietta, now Lockheed. He was retired, last time I spoke with him, and was enjoying his RC airplane hobby.

I met him when he was just starting out his Digital Group, supporting each of the popular CPU's of the mid-70's in a single hardware environment, and, in fact, I've got a couple of his original 256-character display boards (32 characters x 16 lines) modified for 64 character lines.

Normally, when I see a port marked, VGA, I expect it to work with the timing parameters associated with VGA monitors, i.e, nominally 28 Mhz dot clock, and nominally 28 kHz horizontal rate, or whatever it is. There are probably LCD displays that would work with the 640x480 format without having to adhere to the timing. An 805x MCU could probably deal with those and their requirements. I have trouble believing that an 805x can easily manage it, even those 100 MIPS types from SiLabs, with sufficient precision to do the job adequately.

Naturally, if something has to be displayed, someone, meaning some intelligence, has to figure out what, and send it to the display. That's normally some MCU. If the MCU is supposed to generate the timing, too, then I think he'll have his hands full timing out th sync and blanking intervales, and synchronizing writes to the display such that it isn't disturbed by the writes. If the MCU requires external hardware, particularly if it's to be done in programmable logic, the MCU that provides the upper-level intelligence will still be needed, but the logic alone can do the heavy lifting where timing, moving data, translating data, and serializing the intepreted data are concerned. If the second, low-level MCU can't do it all, there's no benefit, IMHO, in using a second MCU at all. I don't believe the 20-40 ns resolution of the 100 MIPS MCU is adequate to time the 18 bits/byte to the three DAC's, or even 6 bits to one.

RE