I²C is a 2-wire serial interface developed by Philips Semiconductor (see I²C-Bus Specification, Version 2.1, January 2000). The bus consists of a data line (SDA) and a clock line (SCL) with pullup structures. When the bus is idle, both SDA and SCL lines are pulled high external. All the I²C compatible devices connect to the I²C bus through open drain I/O pins, SDA and SCL. A controller device, usually a microcontroller (MCU) or a digital signal processor (DSP), controls the bus. The controller device is responsible for generating the SCL signal and device addresses. The controller device also generates specific conditions that indicate the START and STOP of data transfer. A target device receives, transmits data, or both on the bus under control of the controller device.

The TPS65235-1 device works as a target and supports the following data transfer modes, as defined in the I²CBus Specification: standard mode (100 kbps), and fast mode (400 kbps). The interface adds flexibility to the power supply solution, enabling most functions to be programmed to new values depending on the instantaneous application requirements. Register contents remain intact as long as supply voltage remains above 4.5 V (typical).

The data transfer protocol for standard and fast modes is exactly the same; therefore, they are referred to as F/S-mode in this document. The TPS65235-1 device supports 7-bit addressing; 10-bit addressing and general call address are not supported.

The TPS65235-1 device has a 7-bit address set by ADDR pin. Table 7-4 shows how to set the I²C address.

Figure 7-9 I²C Interface Timing Diagram