> I have a circuit with a 16C63 -04I/SO  which works when powered by
> 5.25V but at 5.20V it continually runs part of the code and restarts
> continually.  At 5.00V nothing happens.  Any ideas why it doesn't
> want to work at lower voltages?
>
> Is this an example of it not being programmed "hard enough"?  I
> programmed it using an Advantech LabTool-48 programmer which doesn't
> use the serial programming technique (what it does use I don't know).

It sounds stupid, but have you got the Vcc and Gnd pins connected
to the supply ? You wouldn't be the first person to power up a
circuit through an IO pin and protection diodes and that synario
exhibits the same symptoms.

The Labtool is a pretty good programmer from what I've seen poking a
scope around devices during programming. I'd throw the part back in
the programmer and do a verify to make sure you haven't broken it. If
it verifies, you know that the cells are programmed down to 4.5V (or
whatever you have it set for).

Steve.
======================================================
Steve Baldwin                Electronic Product Design
TLA Microsystems Ltd         Microcontroller Specialists
PO Box 15-680, New Lynn      http://www.tla.co.nz
Auckland, New Zealand        ph  +64 9 820-2221
email: steveb@tla.co.nz      fax +64 9 820-1929
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