> i've got an automotive project based on a 16f877 that works fine in 99% of
applications, but when i
> get it in a car with a magneto ignition, my PIC is freaking out .. resets
/ locks / jumps to random
> locations in code.
>
> Anybody have tips on what I should be doing to 'harden' the PIC against
this kind of noise ? the only
> pins i haven't done anything with are RB6/RB7 which i need open for ICSP.
All other unused pins are
> grounded via 4.7k resistor.

The 12V power supply in cars if very dirty.  You need to filter out spikes
and RF even if it is just going into a +5V regulator.  You also need to pay
careful attention to grounding, ground loops, etc.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, olin@embedinc.com, http://www.embedinc.com

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