Sinclair ZX80 / ZX81 / Z88 Forums

You have two options when programming for the ZX81: Use the ROM interrupt routine, and this displays only text 32x24. Use your own interrupt routine, to generate the display with the same sync timings as the ROM routine. This routine has to be very precise, or it will fail to show on all TVs/monitor...

The Nova program from Wilf Rigter, makes it possible for you to select how many lines you want on your display.

Most calls to ROM uses the registers, so if you want them preserved, you need to save your own content on the stack with a PUSH before and POP after the call. Like A is the main 8-bit register, then HL is the main 16-bit register. So these registers are always used by ROM. B, C, D and E are less lik...

You can read on the detailed documentation of the ZX81, that is written for the emulator NO$ZX. Here you can read that of the 3.25 MHz of the Z80 CPU, only 0.8045 MHz is used for your program. The rest of the CPU time is used for drawing the screen. For the "NTSC"/60Hz version it is even worse. Then...

Great to hear, that something is working. If you need books to help you learn machine code, I have used these books. If you would like to go down to a level where all can learn machine code (even children), I would recommend 'Machine Code for Beginners'. It teaches Z80 and 6502 for most microcompute...

Hi :) I'm trying to find emulators for Lambda 8300. I've found EightyOne, which does great emulation of the Lambda 8300 Then JSZeddy supports Lambda 8300 as well Look like MESS also supports Lambda 8300. This one I havn't tried yet. Edit: Added 12 July 2020 And NO$ZX 2.0 supports Lambda 8300 as well...

It seems like you have a mix of software for ZS1000 and TS2068, and maybe Spectrum.

This device will do the trick https://www.sellmyretro.com/offer/details/ZX8-CCB---video-output-for-ZX81-3712 But it has to be turned very precise, and sometimes it changes after a while. To be honest I have difficulty getting a non rolling/blinking display on my modern VGA screen, even with all the ...

It's one of those games from South America, where you need to set your ZX81 to "NTSC". Because on "PAL" the game is simply too fast.

Copyright Microsoft 1983 -- well is it THAT Microsoft?

Is the Saleae fast enough to sample in the MHz?