The parasitic power from PIC I/O pins may be a real problem
you remove mains power, however PIC will not be in Reset state
and if there is no Brown-Out Circuit it may never start running
when power is applied again.

One should not hope that PIC gets enough power to run from
input pins, and if there is heavy laod on +5 Power rails,
then this situation (parsitic power) may even damage the PIC.

OC Drivers help out, and series current limiting resistors
on PIC pins. Sometimes when there is not enough load on VCC
a ballast resistor from +5 to GND will help too.

and what goes RA4 then I think it is safe to use it as OC
ouput (not for higher than +5/VCC)

>>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
>
>

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