SLUSDF9 June 2020 BQ25790
The device uses I2C compatible interface for flexible charging parameter programming and instantaneous device status reporting. I2C is a bi-directional 2-wire serial interface. Only two open-drain bus lines are required: a serial data line (SDA), and a serial clock line (SCL). Devices can be considered as masters or slaves when performing data transfers. A master is a device which initiates a data transfer on the bus and generates the clock signals to permit that transfer. At that time, any device addressed is considered a slave.
The device operates as a slave device with address 0x6B, receiving control inputs from the master device like micro-controller or digital signal processor through REG00 – REG25. Register read beyond REG25 (0x25), returns 0xFF. The I2C interface supports both standard mode (up to 100 kbits/s), and fast mode (up to 400 kbits/s). When the bus is free, both lines are HIGH. The SDA and SCL pins are open drain and must be connected to the positive supply voltage via a current source or pull-up resistor.