SLUUCN4A January 2023 – February 2024
This command enables the update of the authentication key into the device. The BQ40Z50-R5 device must be in FULL ACCESS mode for the authentication key to update.
To update a new authentication key:
There is no direct read access to the authentication key. After writing the new authentication to the gauge, the gauge will generate an all-zero challenge and provide the corresponding response for verification.
To verify the new authentication key:
The BQ40Z50-R5 device also includes the capability to store the authentication key in secure memory. This is controlled using the SHA1_SECURE data flash bit; however, the authentication key cannot be written into the device using AuthenticationKey() as described above. It must be programmed using a separate method. Also, when using secure memory, the authentication key can only be written once and cannot be changed after it is written.