/diy/ - Do It Yourself

Pic related is my computer i designed and built from the ground up, based around the 65c816 (an iteration on the '02). I started with a 40x4 character display, then built a terminal, and am now designing the graphics card (notice the yellow composite output already on the board) I've given a great deal of thought to this and I've come up with a couple solutions.

A: VLSI makes a composite chip you can talk to over SPI that has sram on it for a frame buffer and supports block move/copy. The only issue is some of the specs are still TBD and so the chip is a bit sketchy, although it's already been successfully used to generate video from an arduino. The model number is vs23s010

B: you can actually generate video off a microcontroller if you know what you're doing, a couple guys have gotten full color ntsc and pal out of very small avrs like the 168.

C: you could generate it using a DAC but you'd need very intimate knowledge of the spec to get any tv or monitor to latch the signal correctly.

D: you can try and dig up old chips like the one you've listed and get them to work, although those chips are getting harder to find and integrate, and many were very power hungry open drain designs that may give you problems.

Ultimately, the choice is yours, I'd recommend A or B, but I'd also recommend building a terminal setup first, so you can learn more of the intricacies of the computer (walk before you run)

A side note, theres a forum: 6502.org, devoted to building and designing these types of machines. There are some very helpful and knowledgeable people on there and they helped me get my project on the right track. I'd recommend asking your question there, and you'll find a couple similar posts, including my own, about how to generate ntsc video.