Sinclair ZX80 / ZX81 / Z88 Forums

The internal ROM function that converts a floating point number to a string is almost certainly the same routine that converts it for printing to the screen.

Mark

Thank you

Mark

The best source of help with the Opus Discovery is to work your way through the topics over on WoSf . And yes I think you can use a PC 3½ inch disk drive. You will have to change either the internal link, zero ohm link or the cable wiring so that the drive responds to the DS0 signal from the Opus Di...

Is the /NMI signal getting to the Z80?

Is the multiface paging out the BASIC ROM and enabling it's own EPROM?

Mark

kmurta wrote: ↑Sat Mar 16, 2024 1:47 pm The Brazilian clones TK82/TK83/TK85 had a joystick input using this scheme. Line A12 is common for keys 6, 7, 8, 0 and line A11 is common for key 5.

The Atari joystick needs to be modified to work in this scheme.

Thank you. That's what I thought.

Mark

Spinnetti wrote: ↑Sat Mar 16, 2024 3:10 am back in 82, I simply cut a hole in the case, put in a joystick port, and hardwired it to the arrow keys... pretty simple....

Ahh, but number 5 key adds complexity. How did you handle "5" being on a separate half row (and hence using a different "common" line to the rest of the keys)?

Mark

There is most definitely a help or example file somewhere, I've seen it. I just can't remember where...

Mark

ZXpand Commander is a file manager/menu/loader program. See this topic...

Mark

The ULA only runs off the +5V. And indeed, the actual supply to the core goes via resistor R34 to pin 13. The ULA has no direct connections to the -5V or +12V supplies. ULA pin 14 just supplies the peripheral interface circuitry. The normal cause of problems with the -5V or +12V supplies, TR4 cookin...

Well, with only seven 4116 DRAM chips fitted, it will do something, but no, it will not run BASIC.

The ULA should however produce a picture. What you get depends on which chip is missing. The effect being different depending on which one it is that is missing.

Mark