Search found 1290 matches

by dr beep
Sat Sep 19, 2020 2:28 pm
Forum: GAMES
Topic: 1 Karat
Replies: 4
Views: 2076

Re: 1 Karat

Bukster wrote: Thu Sep 17, 2020 10:03 am I wrote the base 1k game. It was called Chain Reaction. It's posted here somewhere. It wasn't in hi-res of course.
as mentioned in the source.
by dr beep
Sat Sep 12, 2020 10:01 pm
Forum: WANTED
Topic: Wanted : a ZX81 I/O board extension
Replies: 5
Views: 476

Re: Wanted : a ZX81 I/O board extension

you can use this interface layout as base.

You can use the outputlines with a led and resistance to show your output.

https://trastero.speccy.org/cosas/JL/DrBeep/PC-ZX.html
by dr beep
Thu Jul 30, 2020 9:01 pm
Forum: Development
Topic: "Extreme" 1k programs for ZX80 and ZX81: starter kit
Replies: 14
Views: 6740

Re: "Extreme" 1k programs for ZX80 and ZX81: starter kit

Ok, when I have time.... now on my ipad, not on my laptop.
by dr beep
Thu Jun 11, 2020 12:35 pm
Forum: Development
Topic: ZX81 interrupts with z88dk, how to install an ISR ?
Replies: 19
Views: 3377

Re: ZX81 interrupts with z88dk, how to install an ISR ?

if I got it right, with no device feeding the bus, IM2 will catch any floating byte there and crash ? I guess this is far beyond my technical knowledge :) So if i'm correct, the alternative left is to implement a routine that is called after the display is done, I'm not sure if that's possible to d...
by dr beep
Sun Jun 07, 2020 7:19 pm
Forum: Development
Topic: ZX81 interrupts with z88dk, how to install an ISR ?
Replies: 19
Views: 3377

Re: ZX81 interrupts with z88dk, how to install an ISR ?

Hello, I'm trying to learn how interrupts work on the ZX81 with z88dk. This im2 mode code crashes but it works fine on the Spectrum. I also read that it's possible to install an isr that's called every time the screen is rendered, that is 50 or 60 times each second, anyone knows if that's possible ...
by dr beep
Sat Jun 06, 2020 10:23 pm
Forum: Emulators
Topic: SP-2-ZX81, the new ZX81-emulator for the 48K ZX Spectrum
Replies: 6
Views: 2380

Re: SP-2-ZX81, the new ZX81-emulator for the 48K ZX Spectrum

Well,

A quick scan on WIKIPEDIA tells me that on a ENTERPRISE a full speed ZX81 emulator must be possible, like the SAM-coupe or a ZX Spectrum 128 with interface. Bankswitching must be possible to set memory in order and update screen during intrupt.




Johan "Dr Beep" Koelman
by dr beep
Sat May 30, 2020 10:06 pm
Forum: GAMES
Topic: Random maze generation game
Replies: 4
Views: 1312

Re: Random maze generation game

I did a quick glimpse into the machinecode.

Did you write machinecode or did you crosscompile from C?
by dr beep
Sat May 23, 2020 8:53 pm
Forum: Software
Topic: ZX81 Basic programs loading from shadow ROM
Replies: 15
Views: 2508

Re: ZX81 Basic programs loading from shadow ROM

where do you ldir your program, must be #4009.
#676 is after LINERUN so you execute the next BASIC line of the program.
by dr beep
Thu May 21, 2020 7:59 pm
Forum: Software
Topic: ZX81 Basic programs loading from shadow ROM
Replies: 15
Views: 2508

Re: ZX81 Basic programs loading from shadow ROM

This is the RET-address after LINE-RUN.
If a line holds SAVE then the next line is run.
LOAD continues then where SAVE ended.

Normally a LOAD ends in a screendisplay at #207 which will decrease FRAMES 1x, that is why I suggest doing that too.
You will need it to load my 1K games.
by dr beep
Thu May 21, 2020 7:38 pm
Forum: Software
Topic: ZX81 Basic programs loading from shadow ROM
Replies: 15
Views: 2508

Re: ZX81 Basic programs loading from shadow ROM

Try #676..... I do that in my emulator, but AFTER manually decreasing FRAMES 1x for my games to load.