2 I2C Controller Configuration in the TPS65992S Application Tool

For the TPS65992S to manage the TPS55288 and TUSB1044, the I2C3 controller port must be configured with the correct peripheral addresses and a mapping of command indices to those devices. Using the TPS65992S Application Customization Tool (a GUI for configuring the PD controller firmware), each external I2C peripheral is added with the 7-bit address and assigned an Address Index (an identifier used in the PD firmware). The tool also allows defining sequences of I2C register read and write operations tied to specific PD events (such as power on, attach, contract negotiation, and so on).

In our design, the I2C3 Controller Port is set up as follows:

• TPS55288 (Buck-Boost Converter) – 7-bit I2C address 0x74. This device is added as Address0 (Address Index = 0) in the PD controller I2C controller configuration. We reserve register indices 0 through 8 in the PD controller I2C event table for commands targeting the TPS55288. (Note: 0x74 is the default I2C address of TPS55288 when the device I2CADD pin/mode bit is 0, which matches our configuration.)

• TUSB1044 (USB-C Redriver) – 7-bit I2C address 0x12. This device is added as Address1 (Address Index = 1) in the PD controller’s configuration. We allocate register indices 9 through 28 in the event table for commands to the TUSB1044. (The TUSB1044 address in I2C mode is determined by pin strapping; here the address is configured as 0x12.)

Once the two peripherals and the addresses are defined, the TPS65992S firmware can direct I2C transactions to the correct device using the assigned Address Index. Figure 2-1 shows an example from the TPS65992S GUI: Address0 corresponds to TPS55288 at 0x74, and Address1 corresponds to TUSB1044 at 0x12. With the address map in place, we can then create entries in the PD controller I2C controller Event table. Each entry (indexed by the register index mentioned above) specifies an event trigger, the target peripheral (by Address Index), the register address on that peripheral, data bytes to write (or read), and whether the command is orientation-independent or not. In the following sections, we detail the command sequences configured for each device.

Figure 2-1 TPS65992S GUI Setting On I2C Controller Configuration