8.5.2.2 Level2 Protection
To write to a Level2 protected register, follow these steps:
- Write the address of the destination register, XORed with the protection password (0x7D) to the PASSWORD register.
- Write data to the password-protected register.
- The data is temporarily stored if the content of the PASSWORD register XORed with the address sent in Step 2 matches 0x7D. The register value does not change at this point, but the PASSWORD register is reset to 0x00 after the transaction regardless of whether the XOR logical function matched 0x7D or not.
- Write the address of the destination register, XORed with the protection password (0x7D) to the PASSWORD register.
- Write the same data as in Step 2 to the password protected register.
- The content of the PASSWORD register is XORed again with the address sent in Step 5 must match 0x7D for the data to be valid.
- The register is updated only if both data transfers in Step 2 and Step 5 were valid, and the transferred data matched.
NOTE
No other I2C transaction can occur between Step 2 and Step 5, and the register is not updated if any other transaction occurs between Step 2 and Step 5. The cycle must be repeated for any other register that is Level2 write protected.