The BQ76905 uses a special CONFIG_UPDATE mode to make changes to the data memory settings. Note that this mode is not available for device versions programmed and sealed by TI. Changes made to the data memory settings while the normal measurement and protection functions are in operation can result in unexpected operation or consequences if settings used by the logic change in the midst of operation. When changes to the data memory settings are needed (which generally is only done on the customer manufacturing line or in an offline condition), the host must:

1. Send a command (such as FET_CONTROL()) to disable the protection FETs if they are enabled.
2. Place the device into CONFIG_UPDATE mode by sending the 0x0090 SET_CFGUPDATE() subcommand.
3. Wait for the 0x12 Battery Status()[CFGUPDATE] flag to set.
4. Modify settings as needed by writing updated data memory settings.
5. Send the 0x0092 EXIT_CFGUPDATE() command to resume normal operation.

When in CONFIG_UPDATE mode, the device stops normal operation and stops all measurements and protection monitoring (the protection comparator subsystem is disabled). The host can then make changes to data memory settings. After changes are complete, the host then sends the 0x0092 EXIT_CFGUPDATE() command, at which point the device restarts normal operation using the new data memory settings. As soon as the device enters CONFIG_UPDATE mode, all protection alerts and status faults are cleared. When the device exits CONFIG_UDPATE mode, it performs the startup measurement sequence to determine if any protection faults are present.