The BQ769x2 supports both I2C and SPI communications. The TIDA-010247 uses an I2C isolator, ISO1640, for up to 400-kHz isolated I2C communication between the top BQ769x2 and host MCU. To simplify the hardware design and save MCU resources, two stacked BQ769x2 devices are connected with the I2C bus. The two target BQ769x2 devices share the same I2C address by default, causing conflicts to any host I2C commands. Importantly, the BQ769x2 supports changing the I2C address with one-time programmable memory (OTP), making it easier for host MCU to communicate with two BQ769x2 devices separately without any conflicts. There are two ways to program OTP for the BQ769x2; with the TI GUI or the host MCU. More OTP details are found in the BQ769x2 Calibration and OTP Programming Guide and it is sufficient to perform OTP programming on only the bottom BQ769x2 with a different I2C address. The secondary side of ISO1640 must be powered on before the communications with the top BQ769x2. One way to accomplish this is to add an isolated power module to make sure both sides are powered off of the ISO1640. An easier option is to use the BQ769x202 version of the device, which enables the REG1 3.3-V output by default, and powers both sides of the ISO1640 with BQ769x2 REG1. For the other versions of the device, the top BQ769x2 also needs OTP programming to enable the REG1 output.