Norm Cramer wrote:
>
> I am familure with this requirement but hadn't thought about how to do it
> on a PIC.  Maybe you could throw another PIC at the problem.  The second
> PIC reads the first PIC's ROM and does the check sum.  If needed, the first
> PIC could also check the 2nd PIC's code.  Kind of a round about way of
> doing it but it might work.  The 2nd PIC might be the cheapest approach.
>
> Norm
>
> At 08:19 AM 3/14/97 +0000, you wrote:
> >I want to verify the program at runtime every time
> >it is powered up.
> >
> >Som aplications regarding human safety requires that
> >the processor checks itself for a corrupt program,
> >checks that every used instruction is working ok and
> >checks that every used ram register is working before
> >it can go on with it's safety part of the program.
> >
> >The instruction- and ram-checking is ok but since
> >I can't read the memory with the instructions
> >(Harvard Architecture) I can't do any checksum
> >test.
> >

Why not use a 17CXX ?

--
Friendly Regards

Tjaart van der Walt
mailto:tjaart@wasp.co.za
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