SLUUBT5C November 2018 – June 2021 BQ40Z80
This is a read/write command for 2-word UNSEAL and FULL ACCESS keys.
When reading the keys, data can be read from ManufacturerData() or ManufacturerBlockAccess(). The keys are returned in the following format: aaAAbbBBccCCddDD, where:
Value | Description |
---|---|
AAaa | First word of the UNSEAL key |
BBbb | Second word of the UNSEAL key |
CCcc | First word of the FULL ACCESS key |
DDdd | Second word of the FULL ACCESS key |
The default UNSEAL key is 0x0414 and 0x3672. The default FULL ACCESS key is 0xFFFF and 0xFFFF.
It is highly recommended to change the UNSEAL and FULL ACCESS keys from default.
The keys can only be changed through the ManufacturerBlockAccess().
Example: Change UNSEAL key to 0x1234, 0x5678, and leave the FULL ACCESS as default.
Send an SMBus block write with Command = 0x44.
Data | = MAC command + New UNSEAL key + New FULL ACCESS KEY | |||
= 35 00 34 12 78 56 FF FF FF FF |
The first word of the keys cannot be the same. That means an UNSEAL key with 0xABCD 0x1234 and FULL ACCESS key with 0xABCD 0x5678 are not valid because the first word is the same.
This is because the first word is used as a “detection” for the right command. This also means the first word cannot be the same as any existing MAC command.