I am using a PIC18F26K80, MPLABX, Windows 7.
When I single step through one program, viewing the EEPROM, and there are no instructions to read from or write to the EEPROM, the EEPROM is filled with '*' (FF). Then when I single step through a second program, viewing the EEPROM, and there are no instructions to read from or write to the EEPROM yet, the EEPROM contains several different characters.
First of all, I do not know how the EEPROM can be getting populated at all if I never see any commands to read or write. Secondly, I don't understand how my microcontroller's EEPROM can contain different values between programs without ever reading or writing.
If you can please help explain specifically what is going on in my situation, or even just generally explain EEPROM to help get me on the right track. Also I'm not sure if I am explaining this clearly so feel free to comment and I will elaborate. Thanks.
It's a normal situation, be default empty (erased) EEPROM filled with 0xFF (https://electronics.stackexchange.com/questions/17610/reading-empty-new-at24c16-i2c-eeprom-0xff-or-0x00). And some applications just shows you previously read or predefined instructions. These applications commonly not well developed, so just do not forget to load file before writing to EEPROM, and read EEPROM before saving to file.