To wake-up the gauge from shutdown, a voltage above the VSTARTUP needs to be applied to the PACK pin for a minimum time of 30ms to wake-up the hardware. After the hardware is awake it can take up to 2 seconds for the firmware to initialize and calculate valid gauging results to be available in the registers.
Note:
On startup from shutdown, the gauge relies on the voltage and assumes it to be an OCV (no load and voltage is relaxed). If the voltage is not relaxed on startup it could lead to initial gauge calculations for State of Charge to be incorrect.