SLUUCJ0 November 2023 BQ76907
The BQ76907 device includes Data Memory registers with values stored in digital logic, as well as one-time programmable (OTP) memory, which holds device trim information and default settings for registers. At initial power-up or after a reset, the device loads the OTP settings into registers, which are used by the device logic during operation. The device can also perform a reset on demand if the 0x0012 RESET() subcommand is sent.
The OTP memory is written by TI during device manufacturing and cannot be modified by the customer. A customized OTP configuration can be developed and programmed into a custom device by TI, depending on business terms. For example, with the appropriate OTP configuration the device can power up, load settings from OTP, and operate autonomously without needing host processor support. If interested in this option, please contact TI for further discussion.
For other cases, a host processor generally initializes registers after power up or reset, but registers must be re-initialized after each power cycle or reset of the device. Register values are preserved while the device is in NORMAL, SLEEP, or DEEPSLEEP modes. If the device enters SHUTDOWN mode or a reset occurs, all register memory is cleared, and the device returns to the default parameters when powered again. Even if TI has provided a device with a customized OTP, the customer can still modify register values in system after power-up, in case a different setting is required.
The OTP memory also includes a digital signature, which is stored in OTP. When the device is first powered or after a reset, it reads the OTP settings and checks that the signature matches that stored, to provide robustness against bit errors in reading or corruption of the memory. If a signature error is detected, the device enters SHUTDOWN mode.