Sinclair ZX80 / ZX81 / Z88 Forums

Another thing to think about, is that industry uses microcontrollers and MPU's in all sorts of devices. The requirements are low cost, low pin count, small size and they want the produced systems to be reliable (unlike Windows based systems). Also 8 bit systems used for control applications can be m...

If you use one of the hi-res. systems, I would have thought it possible to load ASCII bit patterns (e.g. like the character set from the ZX Spectrum).
Then when you load a text file, the program could display the ASCII text with out problem

Mark

What can I say, I'm gobsmacked

Well done Andy, keep at it

Mark

I know that back in the day there was a lot of advice to disconnect the 'ear' socket when saving to tape but I never had any issues with this. Anyone here had issues related to feedback loops either in the day or more recently? I think that was/this is more of an issue with the design of some types...

I just looked it up, typical max input voltage is 35V :o but as heat is an issue 11V should stay the maximum unregulated DC input for lang term usage as this was Sinclairs designed for ;) Ah, but what about the poor little electrolytic capacitor on the regulator input (according to the circuit diag...

sirmorris wrote: 10 FORL=54272TO54296:POKEL,0:NEXT

On the C64 is 54272 dec (D400 hex) the "base" address for the SID then?

Mark

SID chips have been interfaced to non-Commodore computers, e.g. there is a design in the UK for an Acorn BBC Micro to interface to a SID. See http://stardot.org.uk/forums/viewtopic.php?f=3&t=2530 If I were to have a go at getting a Z80 based computer to talk to a SID, I would try using two register ...

Hi all Here are three pictures of the Zeddy that I fitted with the ULA replacement module. I was using two "dead" ZX81's and working out the causes of the failures on each. Both had been "played with" by someone before I got my hands on them, as some of the pins on the ROM's and one of the ULA's wer...

If you don't use the Sinclair (and many other) rampacks you could probably get away with replacing the regulator with a short and powering it from an externally regulated 5v supply (I have done this with a ZX81) - (most rampacks I've seen need the 9v, or to be more accurate, 10v to 11v , supply to ...

Hello all! I just realized that the Sinclair ZX81 is about the only computer I know where "you see a screen (with characters)" directly equates to: "the Z80 CPU is functional", and: "the CPU is running (executing code)". And most probably, ROM & RAM too. This directly results from the intimate inte...