We are performing in-circuit test and limited functional testing after circuit board assembly operations. ADuCM360 is purchased preprogrammed and mounted to assembly. We believe flash memory pages are randomly being erased (or otherwise restored to x'FF') and we are looking for potential causes.
We have a subsequent test process that verifies the flash checksum and we've confirmed on multiple units that the checksum was correct prior to the in-circuit test process. The data alteration/erasure does not always occur during the in-circuit testing. However, iteratively performing in-circuit test followed by "checksum verification" shows that eventually the flash content is altered.
There is no in-circuit "vector test" that is directly targetted at testing this device so we do not believe any testing is purposely writing to any internal registers or purposely attempting to erase or alter flash pages.
We are looking for ideas/suggestions for potential causes, or anyone with similar experience and anything that was found to resolve the problem.
Thanks - Dan