Prevention of EEPROM Data Corruption

Question: After correctly enumerating for a number of times, an FX2LP device all of a sudden comes up as "Cypress FX2LP - EEPROM Missing". Why does this happen?



The I2C EEPROM interfaced to the FX2LP chips is vulnerable to data corruption during device power up and power down.  If the first data byte is corrupted, a c2 load can no longer happen from the EEPROM. Hence, no firmware is downloaded to the onchip RAM of FX2LP and it enumerates with the default VID/PID of 04B4/8613. To protect the EEPROM from possible data corruption during power up and power down, a few precautions can be taken. Application Note AN5078 describes in detail the design guidelines for assuring the data integrity of serial EEPROM devices when used in FX2LP designs.