The BQ76922 device implements a signature check on the instruction ROM for the internal processor at initial power up or upon reset. If this fails, the device can trigger a Permanent Fail (PF) and disable the battery pack. This PF can be enabled by setting the Settings:Permanent Failure:Enabled PF C[IRMF] configuration bit (this bit is enabled by default).

The device also implements a signature check at initial power up or after reset on the internal processor data ROM, which holds default values for the device configuration. If this fails, the device can trigger a Permanent Fail (PF) and disable the battery pack. This PF can be enabled by setting the Settings:Permanent Failure:Enabled PF C[DRMF] configuration bit (this bit is enabled by default).

The device also implements a signature check at initial power up or after reset on the internal OTP memory, which may contain customer configuration data. If the OTP memory signature check fails, the device will not load customer settings from OTP, it will instead load the default configuration, trigger a Permanent Fail (PF), which keeps the FETs turned off (but will not blow the fuse) and the REG1 LDO disabled. This PF is enabled by setting the Settings:Permanent Failure:Enabled PF C[OTPF] configuration bit (this bit is enabled by default). Note that the OTP signature does not include the Manufacturing Data (available using the 0x0070 MANU_DATA() subcommand) nor any PF status data which was previously written to OTP (which is read using the 0x0053 SAVED_PF_STATUS() subcommand).

The BQ76922 device implements a signature check of the factory trim information within the device after initial power-up and any device reset. If this check fails, the device begins the transition into SHUTDOWN mode.