Search found 60 matches

by Bean
Tue Jul 30, 2019 2:06 am
Forum: Development
Topic: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)
Replies: 32
Views: 8355

Re: New hardware I/O board using Parallax Propeller

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...
by Bean
Sun Jul 28, 2019 8:11 pm
Forum: Development
Topic: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)
Replies: 32
Views: 8355

Re: New hardware I/O board using Parallax Propeller

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...
by Bean
Thu Jul 18, 2019 2:42 am
Forum: Sinclair Misc
Topic: Why did Sinclair resist Floppy drives for it's computers ?
Replies: 4
Views: 2094

Why did Sinclair resist Floppy drives for it's computers ?

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 ...
by Bean
Sun Jun 16, 2019 4:59 pm
Forum: Development
Topic: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)
Replies: 32
Views: 8355

Re: New hardware I/O board using Parallax Propeller

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
by Bean
Thu Jun 13, 2019 4:02 pm
Forum: Sinclair Misc
Topic: Did the original ZX80 "new" ROM really contain.....
Replies: 3
Views: 2320

Re: Did the original ZX80 "new" ROM really contain.....

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...
by Bean
Thu Jun 13, 2019 1:48 pm
Forum: Development
Topic: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)
Replies: 32
Views: 8355

Re: New hardware I/O board using Parallax Propeller

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
by Bean
Thu Jun 13, 2019 2:56 am
Forum: Development
Topic: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)
Replies: 32
Views: 8355

Re: New hardware I/O board using Parallax Propeller

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...
by Bean
Wed Jun 12, 2019 9:05 pm
Forum: Development
Topic: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)
Replies: 32
Views: 8355

Re: New hardware I/O board using Parallax Propeller

It could make VGA or composite video, but it would be an independent screen (it would not be a copy of what is on the normal screen). This is because I don't have enough address lines to monitor that much memory (I only have access to 4 addresses). LIkewise, with the keyboard. It could support a PS/...
by Bean
Wed Jun 12, 2019 3:53 pm
Forum: Development
Topic: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)
Replies: 32
Views: 8355

Re: New hardware I/O board using Parallax Propeller

Hey Tim, Yeah I saw them, but they are "out of stock". I tried modifying a longer connector, but I made a mess of it. It's good enough to test with. I am really just wondering what connectors to put on the board, RCA, VGA, etc. I think it will also have a row of pin so you can connect a daughterboar...
by Bean
Wed Jun 12, 2019 12:23 am
Forum: Development
Topic: New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)
Replies: 32
Views: 8355

New hardware I/O board using Parallax Propeller (VGA,Sound,Joystick,etc)

Hey guys, I'm working on a new hardware project. An I/O board for the ZX81 based on the Parallax Propeller. I want to keep it very simple and able to be made from all thru-hole parts. It's a very simple board with the propeller being fast enough to handle all the bus timing. Anyway, it currently is ...