Not to mention "Son of Cheap" video. My favorite TVT was Dr. Robert Suddings TVT (Digital Group ~1977).

When folks indicate they want to build a VGA circuit i often think they really mean they want VGA like display capability which is a different proposition.

Myself, i'm not that interested in building a PC compatible "VGA" circuit. Programmable Logic is, no doubt, one good way to do this.

I am interested in exploiting modern commodity video technology, especially cheap LCD displays. The NTSC TVT works great with those "in car" type displays from AudioVox and Alpine. Tempting enough to argue for a color solution.

I find 15" LCD VGA monitors are pretty easy to get inexpensively.

If your willing to work with monochrome, no problem using a shift register.

I have no doubt that a mono 640x480 VGA display can be generated by a DS'420 + shift register.

The memory again is the issue for me. 8 color VGA would probably argue for a "Fly-by" technique where 3 Shift Registers load directly with the processor generating the dummy reads from 3 memories (no processor data intervention).

I did this many years ago in an 8751 audio playback/recorder sampler to allow 16 bit x 256k DRAMs to be directly written and read from 12 bit ADC/DAC @ 32kHz.

regards,
p