Date   : Sun, 28 Dec 2008 23:12:59 +0000
From   : afra@... (Phill Harvey-Smith)
Subject: OT: ZX80 ROM ?

Mark Haysman wrote:
> Oops, just need to correct myself there, the TMS2532 has A11 on pin 18 
> instead of 21 compared to a 2732, and some other programming/select pins are 
> messed with. But according to the diagram I have for the ZX80, the 2732 is 
> the correct type.
> 
> If for some reason my diagram is wonky, and you DO need a TMS2532, then let 
> me know, I've got those as well.

I have the actual sinclair ZX80 assembly instructions here (paper based 
no less), and on the component list, it lists IC2 (the rom) as 8232 or 
TMS4732. The circuit diagram also has A11 on pin 18, CS on pin 20 and 
A12 on pin 21, note this is a mask programed rom, so doesn't need a 
programming pin so can have an extra address line. This is the pin I 
needed to cut on my board.

Just found the assembily instructions on the web here :-

http://www.zx81.de/english/zx80_e.htm

I have seen a re-drawn schematic for the ZX80 that does list a 2732, so 
that may be the one you have seen.

Cheers.

Phill.


-- 
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.