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 baud-rate detection, and IrDA. Each USCI module contains two portions, A and B.
The USCI_An module provides support for SPI (3- or 4-pin), UART, enhanced UART, or IrDA.
The USCI_Bn module provides support for SPI (3- or 4-pin) or I2C.
The MSP430F524x and MSP430F523x series include two complete USCI modules (n = 0, 1).