On the BQ79631EVM there are 8 GPIO pins that can be used for a variety of purposes and can be configured in the following manners:

• ADC and OTUT inputs
• ADC only input
• Digital input
• Output high
• Output low
• ADC input and weak pull-up
• ADC input and weak pull down

Signals from each of the GPIO pins flows through an ADC from within the BQ79631-Q1 much like the VC pins used to measure the high voltage branches. However, unlike the VC pins, the GPIO pins can be configured to flow through the main ADC, which has a digital low pass filter, or to flow through an AUX ADC that does not have this LPF present. If the user intends to make measurements that prioritize low latency over high accuracy, then TI recommends to configure the GPIO pins to use the AUX ADC.

The user can access GPIO1-3 on the connection points near the center of the board and GPIO4-8 on J5 located just above the BQ79631-Q1 device. Only the GPIO4-8 pins on J5 must be used to measure external thermistor inputs as the GPIO1-3 pins are used to control FET switches throughout the EVM. GPIO4-7 can also be used as Controller SPI pins to control external devices such as EEPROM or Relay/Contactor Driver.