JAJSSO2 December 2023 MCF8315C
PRODMIX
MCF8315C provides configurable read and write protection to EEPROM registers. The level of protection can be configured using EEPROM_RW_PROTECTION as per following list,
Passcode is a 30-bit number composed from the EEPROM section as shown in Figure 6-54.
When passcode based read/write protection is enabled, every EEPROM read/write transaction has to be preceded by a valid passcode write to appropriate address. EEPROM read/write transaction has to be initiated within 500-ms of valid passcode write - once 500-ms lapses, valid passcode has to be written again to the appropriate address to enable subsequent EEPROM read/write transaction. If an invalid passcode is written, the subsequent EEPROM read/write transaction is rejected, number of consecutive invalid passcode attempts logged and nFAULT is pulled low to indicate failed EEPROM transaction. Number of consecutive invalid passcode attempts is reset to zero and nFAULT is cleared on subsequent valid passcode write as long as the number of consecutive invalid passcode attempts is < 3. On the third consecutive invalid passcode attempt, the EEPROM is locked permanently and no further EEPROM read/write transactions are allowed even with valid passcode. The read/write protection is applicable to EEPROM as well as corresponding shadow RAM locations. The EEPROM_RW_PROTECTION as well as the passcode are part of the EEPROM registers and hence same level of read/write protection applies to these bit fields as configured by EEPROM_RW_PROTECTION.