The USCI modules are used for serial data communication. The USCI module supports synchronous communication protocols such as SPI (3- or 4-pin) and I2C, and asynchronous communication protocols such as UART, enhanced UART with automatic baudrate detection, and IrDA. Each USCI module contains two modules, A and B.
The USCI_Ax module provides support for SPI (3- or 4-pin), UART, enhanced UART, or IrDA.
The USCI_Bx module provides support for SPI (3- or 4-pin) or I2C.