Hi all,

I am a newbie of this mailing. A question has been puzzling me and I want
to get some answers.

I am a programmer writing software for microchips. I just wrote one for a
product. When the engineers started testing it with noises and sparks of
voltages, the software failed. I debugged the software and found that the
noises caused the interrupt routine stop running, as if the T0IE had been
reset to clear.


I then wrote a routine to watch the interrupt; if it stops running I will
use watchdog to restart the whole program. That works fine. Thus also
proved that the noises did cause the interrupt stop running.


Now this is my question: Can someone explain to me why the noises can
change the value of the registers of the program? If it can change T0IE,
what else would it change? I can't monitor all the variables; the thought
that the noises can change values arbitrarily is very scary. It could be a
disaster.

Someone suggested me reset the program periodically. (For example, use
watchdog and alike.) If so, is this a common practice that should be used
on all projects?

I believe there is some official guidance on this matter. Can someone
enlighten me?

Thanks alot!!

Tony Pan

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