Search found 37 matches

by Bean
Sun Jun 16, 2019 4:59 pm
Forum: Development
Topic: New hardware I/O board using Parallax Propeller
Replies: 14
Views: 635

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: 647

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
Replies: 14
Views: 635

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
Replies: 14
Views: 635

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
Replies: 14
Views: 635

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
Replies: 14
Views: 635

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
Replies: 14
Views: 635

New hardware I/O board using Parallax Propeller

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 ...
by Bean
Thu Apr 18, 2019 6:01 pm
Forum: Hardware
Topic: NOOO.. My just arrived TS 1500 is flakey!
Replies: 10
Views: 764

Re: NOOO.. My just arrived TS 1500 is flakey!

If you haven't sent it back yet. Try connecting a 16K RAM pack and see if it boots.
I have one that does that and it has bad RAM, and I just use it with a RAM pack attached.

Bean
by Bean
Thu Apr 26, 2018 2:17 pm
Forum: Development
Topic: Pretty fast Mandelbrot set generator...
Replies: 2
Views: 730

Re: Pretty fast Mandelbrot set generator...

I have updated the mandelbrot drawing program.
I now use 4.12 fixed point math so you can zoom in further.
I also added a couple more features (print, set max depth, etc).

I think this is quite a good demonstration program for the good ol' zeddy.

Bean
by Bean
Mon Apr 23, 2018 7:06 pm
Forum: Development
Topic: Pretty fast Mandelbrot set generator...
Replies: 2
Views: 730

Re: Pretty fast Mandelbrot set generator...

I noticed if you zoom in too much it just goes blank. I think the increment goes to zero.
I am using 8.8 fixed point math in the asm. I guess I could use 4.12 and get more zoom.

Bean