SLDS187A October 2018 – December 2019 TPS65216
Registers 0x11h through 0x26h are protected against accidental write by a 8-bit password. The password must be written prior to writing to a protected register and automatically resets to 0x00h after the next I2C transaction, regardless of the register accessed or transaction type (read or write). The password is required for write access only and is not required for read access.
To write to a protected register:
The cycle must be repeated for any other register that is Level1 write protected.