Hi,
I'm using the emulated EEPROM feature on the S32K148, always configured for Normal Write mode.
To write anything to EEPROM, I use functions that check the CCIF bit in FTFC->FSTAT before and after writing and return only after CCIF is 1 to ensure that writes are completed and cannot collide.
At boot after setting FlexRAM to EEEPROM mode, I make a status query according to AN11983 chapter 3.2.1.4 to read the brownout code. Usually this is 0 and everything is fine.
However, sometimes on some devices after some time of usage, this brownout status reads as 4, indicating an interrupted normal write. The strange thing is, that once this status becomes 4, it will always stay at 4 forever on this device, even after many reboots and software updates!
Now I got two questions:
1.) AN11983 states that there is no dedicated repair or maintenance command needed for normal writes. So there is no way for me to actively do anything when brownout status=4 is read. The old values in EEPROM should have been restored automatically. Right?
2.) When / how is the brownout status reset to 0? If I can't do any manual repairs, this has to happen automatically somewhere. I would have thought that it's back to 0 after the next reset (as long as no new write interruption has occurred), but this isn't the case. Apparently this status 4 is persistent until a mass-erase? Please explain.
