>> My vendors also keep asking me for a checksum for PICs.  Since
>> there are many ways to calculate checksums, it's pretty hard
>> to figure out what they want.  They don't know either:  their
>> programmer s/w just gives them a bunch of hex digits as a
>> checksum and they don't know how it was calculated.
>
> MPLAB does seem to use the method that seems to have become a defacto
> standard for programmers. I would suggest you quote the checksum that MPLAB
> gives you, and then let them see if it matches what they get. If it doesn't,
> then start trying to find out the method.

There used to be a very specific method to calculate the checksum for 
each PIC chip. Not any longer ? Anyway, because of code protection, the 
checksum may not be what one thinks it is. Especially if a third party 
programmer is to be used. So do what Microchip says: program the chip, 
read it back, and take that checksum as the one to be used. No ? (I know 
that this does not work on some chips which have 'opaque' protection).

Peter
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