SLUUC54C February 2020 – March 2024 BQ27Z558 , BQ27Z561 , BQ27Z561-R2
The gas gauge has a key access scheme to transition between SEALED, UNSEALED, and FULL ACCESS modes. Each transition requires that a unique set of two keys be sent to the gas gauge via the AltManufacturerAccess() command. The keys must be sent consecutively, with no other data being written to the AltManufacturerAccess() register. The Seal Device command instructs the device to limit access to the registers, functions, and data flash space, and sets the [SEC1][SEC0] flags. In SEALED mode, standard register information is accessible. Extended MAC Command functions and data flash are not accessible. Once in SEALED mode, the device can never permanently return to UNSEALED or FULL ACCESS modes. Section 12.8.33, the OperationStatusB() register, shows the status of the device using the [SEC1][SEC0] bits.