CMOS for NMOS

[allison]

On 04/15/2018 10:25 AM, David Griffith via cctalk wrote:
>
> I'm pondering upgrading the CPU of a Pacccomm Tiny-2 Mk2 radio packet
> controller from a 6Mhz Z80 processor and SIO to 10Mhz parts.  My
> problem is that the parts already in it appear to be NMOS.  The family
> is still being made by Zilog, but for 10Mhz parts, CMOS is all they
> have.  Can I just drop in CMOS, change out the crystal/oscillator and
> have things work as expected?
>
No, and why?

Changing to CMOS can cut power drain.  However speeding up clocks can
make the packet controller
broken even if it runs!  If you keep the 6mhz clock all will be fine.

You do not want to alter the output data rate to the modem side.  Also
the other devices on the bus have
to be able to run at 10mhz.

I have in the past upgraded my AmproLB+ to CMOS but that was to lower
power needs for
battery operation.  However there was no intent to go faster.


Allison


> Here's what are fitted to my TNC.
>
> Z84C00BB6
> Z80BCPU
> 29125
>
> Z8440BB1
> Z80BSIO-O
> 29014
>