Outside of all the WDT suggestions, what circuitry is he allowed to put o=
n? =20
I'm thinking that discharging a capacitor and measuring with an a/d or=20
comparator input could also provide a fairly accurate pic-clock-independe=
nt=20
time reference.

Cheers,
-Neil.



On Tuesday 06 May 2003 20:45, William Chops Westfield scribbled:
>     To rephrase it, he thinks that he can figure out, in software, the
> number of MIPS of the machine he is running on.
>
> You can come up with a "reasonable" guess as to clock speed on a PIC or
> related processor by seeing how many instructions it will execute in
> between watchdog timeouts (the WDT timer is normally a separate RC
> controlled clock, I believe.)  You could probably get a bit closer with
> a single resistor and cap connected to an IO pin, PERHAPS even using th=
e
> pin's inherent capacitance and leakage...
>
> It depends how accurate he needs to be, and whether he's allowed to mak=
e
> baseline measurements to compare to, and so on...
>
> BillW

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