Eeprom accidentally erased?

[BrianT]

Hello Josuetas,
I recently had a similar issue with the PIC 18LF4620. Here the battery running the system went completely flat so the processor was working well off the datasheet and out in no mans land. I had six systems all display an identical fault. The same three locations in EEROM were scrambled. These were at locations 44, 45 and 47 (decimal). These cells are read by the code every hour but are NEVER written to by the code other than via the DATA statement at program load time.

What was particularly noticeable was that the flash program code memory was all FF from about location 60 to the top of memory. All six showed exactly the same erasure. LVP is turned off in the configuration fuses and the PGM, PGC, PGD and LVP pins are all floating.

Because the code memory was all erased the bootloader would not work so retrieving data from the external was a challenge. In future all my boards will have ICSP pinouts to a header as well as the bootloader.

HTH
Brian