5.6.1 Universal Synchronous and Asynchronous Serial Receiver and Transmitter (USART)

AVR and PIC32CM MCUs provide highly flexible and robust USART peripherals. Both USART variants support buffered communication, interrupt-driven operation, and operation in low-power modes, making them suitable for a variety of embedded communication needs. Table 5-21 shows a comparison of features between AVR and PIC32CM.

Table 5-21. AVR® and PIC32CM UART Features
Feature	AVR® USART	PIC32CM USART (SERCOM)
Integration	Stand-alone USART peripheral	Mode in SERCOM (Serial Communications) peripheral
Operation Modes	Full-duplex Half-duplex synchronous/asynchronous	Full-duplex Half-duplex Synchronous/asynchronous
Protocol/ Standard Support	IrDA® LIN client SPI host RS-485	Varies per device family: IrDA® LIN host/client ISO 7816 (smart card) RS-485
Buffer/FIFO	Two-level transmit/receive buffer	16-byte transmit/receive FIFO
Baud Rate Generation	Fractional, from any peripheral clock	Baud rate generator, internal/external clock
Data Bits	5, 6, 7, 8, 9	5, 6, 7, 8, 9
Stop Bits	One or two	One or two
Parity	Odd, even, none	Odd, even, none
Data Order	N/A	LSb or MSb first selectable
Flow Control	N/A	Request-to-Send (RTS) and Clear-to-Send (CTS) hardware flow control
DMA Support	N/A	Supported
Error Detection	Parity Buffer overflow Frame error Noise filtering	Parity Buffer overflow Frame error Noise filtering Collision detection
Sleep Mode Operation	Supported	Supported
Interrupts	Separate for TX complete, TX data empty, RX complete	Multiple, including FIFO events
Pin Mapping	Fixed	Flexible