> >> Why do you want to do this?
>
> To comply with the UL1998 requirement, I need to test the integrity of the
> ROM. The chip that I am using is not capable of accessing program memory.
> Therefore the UL engineer told me that I can perform instruction set test
> instead. But he didn't tell me how to do it.

An instruction set test won't test the whole ROM, only the locations that
hold the instruction you end up testing.  In other words, you will only be
verifying the ROM data paths.  The individul ROM locations you will verify
will be exactly those that DON'T matter in normal operation.  The normal
procedure for testing ROM is to perform a checksum.  If the machine can't
read its own ROM, then you probably can't comply with that requirement using
that machine.

A last desparate method would be to use the ROM programming feature to read
it out and perform the checksum, but that would require external hardware.
A different PIC that can read its own program memory would be cheaper.  Of
course how do you know then that the ROM holding the checksum algorithm
didn't flake out and cause the routine to report everything is OK?


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