At 02:22 PM 20/02/97 -0500, you wrote:
>Well, I've had a similar problem with a PIC16C55 running itself off
>external sensor input lines!  I finnally had to use a relay that shut the
>Vcc to GND after the power was off (the inputs didn't have enough current
>to drive the relay without main power)  In the future I plan to use optical
>isolation to eliminate the problem...  I wish there was a slicker way...
>Anybody know how to ensure the PIC will shut off even with voltage applied
>to its inputs/outputs?

Why does it HAVE to shut off if there's enough power to run it from
the sensor lines ? Unless its a power waste - just use another I/O pin
to read the power etc So if it keeps running then effectively make it
do nothing by a continuous loop - or think up some clever way for it
to do something (useful) when its not running - like self tests }:o)

Rgds

Mike


Some say there is no magic but, all things begin with thought then it becomes
academic, then some poor slob works out a practical way to implement all that
theory, this is called Engineering - for most people another form of magic.
                                                                       Massen