1.2.2. Erase and Reprogram Sequence
The differences between the UFM block and serial EEPROMs that you should consider in your integration of serial EEPROM applications are the sector-based erase and erase/reprogram cycles. Serial EEPROMs support byte-wide erase, which is automatically implemented during a byte write sequence. The UFM block supports byte writes, but does not support byte erase, requiring a sector-based erase sequence prior to any programming or writing. If the data content of a specific byte location needs to be overwritten in the UFM, the entire sector that the byte resides in must be erased unless the byte location was already erased (all 1s). For programming endurance, the UFM erase/reprogram cycles do not meet the 107 and greater cycles seen in serial EEPROMs.