and3rson wrote:
Yes, I've been thinking about video a lot.
Because it would simplify debugging a lot.
and3rson wrote:
- VIC chip: this would totally be cheating!
Aha, so
EF9345 would be cheating, too. //PDF page 14
Same thing for EF9367 and TMS9918.
and3rson wrote:
Some serious (and esoteric) options:
- As you mentioned - discrete logic: Having a simple video like Apple-1 made purely of basic components would be really fun, but I'm afraid it might end up being really big (and complex!).
But that's a totally viable option, I could even design in a PC-card style and plug it into my main SBC. Though this would mean my SBC is no longer a SBC, but a DBC!
That's right.
My solution was to make the TTL CRT controller a separate unit, running with its own clock, mirroring 6502 write cycles into its own display RAM.
So that the SBC doesn't need to be changed, and is able to work without the CRT controller being attached to it.
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and3rson wrote:
- Second 6502 & DMA: It would be interesting to have a separate 6502 solely to render video.
Instead of DMA, second 6502 could have its own RAM and some glue logic to sync it with primary data bus.
Either that, or two 6502 CPUs sharing the same RAM chip.
Hmm... looks like Mouser doesn't have IDT dual port RAMs anymore, and I don't have any practical experience with that W65C02 BE pin...
and3rson wrote:
- *Heresy alert!!!* - Z80: I never actually developed for it, but I own several Speccies (originals as well as few clones from soviet era).
Would be fun to try and make it lean under 6502's control and handle video rendering, just for the sake of it.
Yes, this would be more fun than just adding a microcontroller to a 6502 system for video signal generation...
and3rson wrote:
- Some exotic "video"-interfaces: a printer? A matrix of nixie tubes with shift registers? (Damn, that's gonna cost a fortune.) Etch-a-sketch with two stepper motors?
elm-chan Laser projector, or
dot flippers ?
"oscilloscope vector display" probably would be boring, because there are a lot of oscilloscope clock projects in the internet...
and3rson wrote:
But really, my main fetish is composite video. I always liked it - I grew up with it, it had a nice round connector and always worked with no effort whatsoever.
And all the artifacts like noise & jailbars just add to the atmosphere. I suck at analog electronics, but a possibility of generating composite video signal makes me want to learn it better!
As long as you don't want to use/display colors, genenerating a composite video signal isn't
"rocket science".