Hello everyone, I'm new here

[LD A 00]

Ciao a tutti, sono nuovo qui.
Ho sempre avuto una passione per l'elettronica in generale.
Riprendendo il mio zx80 volevo ricostruirlo, vedo molte informazioni su di esso online, ma non sono un buon programmatore. Ho studiato lo Z80 35 anni fa, ricordo poco.
Grazie a voi ho scoperto molti segreti della zx80. Da qui l'idea di clonarla perché è la più semplice in termini di componenti. Non ha ula. Ho alcune domande da porre prima di iniziare un lavoro forse inutile..
Se volessi fare una Zx81 senza ula ho trovato interessante lo schema di Andy Rea per sostituire l'ula con componenti hc.
Ma mi chiedo se funziona al 100% come un ula Zx81? Anche veloce e lento?
Poi vorrei overcloccarlo ma ho già risolto..
Per quanto riguarda il programma in rom, ho clonato il Basic originale e clonato il quarto su due eprom 27c32. Sarei interessato a caricare il firmware 16k Zx81 su un eprom per avere più funzioni.. Qualcuno può aiutarmi? Mi dispiace per aver scritto con il transletor di Google.

[1024MAK]

Translated to English:

Hi everyone, I'm new here.
I have always had a passion for electronics in general.
Taking up my ZX80 I wanted to reconstruct it, I see a lot of information on it online, but I'm not a good programmer. I studied the Z80 35 years ago, I remember little.
Thanks to you I discovered many secrets of the ZX80. Hence the idea of cloning it because it is the simplest in terms of components. It has no ULA. I have some questions to ask before starting a perhaps useless job ..
If I wanted to do a ZX81 without ULA I found the Andy Rea scheme interesting to replace the ULA with HC components.
But I wonder if it works 100% like a ZX81 ULA? Even fast and slow?
Then I would like to overclocched it but I have already solved ..
As for the program in ROM, I cloned the original BASIC and cloned the fourth on two EPROM 27C32. I would be interested in loading the 16k ZX81 firmware on an EPROM to have more functions .. can anyone help me? I'm sorry for writing with Google's translettor.

Hello and welcome to our forum LD A 00!



I get the impression that you may think that you have posted in English. However, your post appears to be Italian.

I hope you enjoy this forum

You are welcome to ask questions!

We much prefer that you ask your questions in the relevant sub-forum. If there isn't an existing topic that covers your question, then please create a new topic.

I believe Andy Rea's ZX81 logic chip design (that replaces the ULA) does work like a normal ZX81. And does support FAST and SLOW modes.

There are also at least two other designs of clone ZX81s that use logic chips instead of a ULA.

Programming an EPROM with the ZX81 ROM is indeed possible. Various members here have done just that. You should consider the ZX81X2C ROM. See this topic ZX81X2.ROM - and the big bang

Mark