Sinclair ZX80 / ZX81 / Z88 Forums

Personally I think it's not interesting, as it will only work with software custom made for the device. True, that is a fair point. The advantage is that you can run the ZX81 in FAST mode, which really unleashes the speed. Machine code is crazy fast.. I don't plan to sell a bunch of these. It is mo...

I haven't heard from anyone... I have pretty much decided on: VGA 640x200 2 color VGA 256x192 4 color (2 pages for page flippin' games) VGA 160x100 64 color Stereo sound (3 voices+1PWM left, 3 voices+1PWM right) Wii Classic Controller for joystick I plan to offer it as a kit for about $100 - $150. A...

I am working on the VGA modes and I was wondering what everyone thought would be good modes to have for games and such. I have about 16K for video memory and maybe another 2-4K for palette info. So with that in mind here is what I came up with. Text: 80x25 (not sure about what is possible for colors...

Martin, Yeah, that is the bad part. This is only an I/O board with an on-board processor. So there is no code "built-in" that the ZX81 can run. I wish the ZXPand had a pass-thru connector. I have put a 16K RAM on it just because my board doesn't have a pass-thru either. Just the be clear, the VGA an...

A couple questions... Is there something small I can type-in to see if my 16K memory supports true hi-res ? Second, should I support atari joysticks/paddles or Wii NunChuk/Classic controller ? Third, I plan to support VGA, but what about composite video ? Right now it is going to have: VGA Text 80x6...

I am just wondering why Sinclair was so resistant to making floppy drives for the ZX81 and Spectrum computers ? I believe this is what kept them firmly in the "toy" or "game" computer category. Certainly not seen as a "real" computer by much of the public. I know they would have been expensive, but ...

Does this look correct for 16K that is True Hi-Res compatible ?

P.S. I forgot to show that /RAMCS is tied high too.

Thanks,
Bean

Somewhere I saw a picture of the prototype keyboard and it did have those keywords. The story I heard was when the printer was developed those commands had to be removed since the ZX81 pretty much has to do all of the printer control. This is a shame, as those commands would have been really nice to...

I've decided to put the 16K of RAM on my board also.
Can someone explain what I have to do so that it support true Hi-Res mode ?
And maybe why it needs to be done ?

Thanks,
Bean

Tim, Thanks for the offer. I'd like to find a source for the proper connector because I would like to sell these as a kit. I'm using all thru-hole parts. If it is popular, I might redesign for surface mount parts and sell it already built. After I get the design finalized I'd like to send you one to...