CPD fuse problem

[Ömer Faruk]

Hello everyone

When i program pic16f877a sometimes i forget unchecking the eeprom data write section on pickit2. Because i do some eeprom writings and i don't want them to be lost. In recent days i have learned that CPD fuse of pic16f877a inhibits external data writings and readings. Although i write 0 on CPD fuse (İ also checked CPD is 0 in the pickit2). Pickit2 sets all the eeprom data to FF. What am i doing wrong? (By the way when i try to read the eeprom data pickit2 reads all 0).

[Ttelmah]

You need to change the erase mode, to 'erase when needed'. Otherwise the
programmer may be fully erasing the chip, which will overwrite the CPD
fuse.

<https://www.ccsinfo.com/forum/viewtopic.php?t=30621>

The PicKit2, is not terribly 'friendly' about this.