1 Peripheral Overview

The EUSART module is a serial Input/Output (I/O) communications peripheral. It contains all the clock generators, shift registers and data buffers necessary to perform an input or output serial data transfer, independent of device program execution. The EUSART, also known as a Serial Communications Interface (SCI), can be configured as a full-duplex asynchronous system or half-duplex synchronous system. The Full-Duplex mode is useful for communications with peripheral systems, such as CRT terminals and personal computers. The Half-Duplex Synchronous mode is intended for communications with peripheral devices, such as A/D or D/A integrated circuits, serial EEPROMs or other microcontrollers. These devices typically do not have internal clocks for baud rate generation and require the external clock signal provided by a Host synchronous device.

The RXx/DTx and TXx/CKx input pins are selected with the RXxPPS and TXxPPS registers, respectively. TXx, CKx and DTx output pins are selected with each of the pin’s RxyPPS register. Since the RX input is coupled with the DT output in Synchronous mode, it is the user’s responsibility to select the same pin for both of these functions when operating in Synchronous mode. The EUSART module will control the data direction drivers automatically.