Z80 / Z84C Swap (Doh!)

Eric Smith spacewar at gmail.com
Mon Aug 17 13:55:59 CDT 2015

On Mon, Aug 17, 2015 at 11:40 AM, Sean Caron <scaron at umich.edu> wrote:
>if you put a 5V CMOS Z80 in there, I wouldn't expect it to
> really hurt anything; it might not run exactly right depending on
> tolerances in the system design I would suspect mostly due to (a) logic
> threshold differences and (b) fan-out differences especially given one
> logic family driving another ... but I wouldn't expect it to really damage
> anything.

While that tends to be true for CMOS parts in general, the CMOS Z80
was designed to meet the same I/O specs (voltages and fanount) as the
NMOS part.

It's possible that the NMOS part has more margin for operation outside
the specs, particularly for Vih and Vihc, but is the computer is
designed properly that shouldn't matter.

More information about the cctech mailing list