Sinclair ZX80 / ZX81 / Z88 Forums

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/...

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...

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 ...

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

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

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

I wrote a program a play with the Mandelbrot set.
Uses ASM to draw the set and BASIC to handle the user interface.
Takes about 85 seconds in slow mode (NTSC) or about 16 seconds in fast mode.

Comments welcome...

Bean

Moggy,
I will make the characters different so the UDG can work better.
I'll use inverse periods for the top section, etc...

Bean

Sirmorris,
I will post the source after I get a little further along. It's kind of a mess right now as I am just "making it work".

Actually what the heck, here it is...

Bean

P.S. What I could use is some help with the graphics, I'm not an artistic person...

Use
; Jump = 1,Q,A,zero,P,enter,space
; Shoot = 2,W,S,Z,9,O,L,period

Ship moves and launches bomb that create craters. You can shoot the ship.
If you don't jump a crater, you get returned to BASIC.

Comments Welcome...
Bean