25.3.3 Communication Modes

The USART is a flexible peripheral that supports multiple communication protocols. The available modes of operation can be divided into two groups: Synchronous and asynchronous communication.

Synchronous communication relies on one device on the bus acting as the host, providing the other devices with a clock signal through the XCK pin. All devices use this common clock signal for both transmission and reception, requiring no additional synchronization mechanism.

The device can be configured to operate either as a host or as a client on the synchronous bus.

Asynchronous communication does not use a common clock signal. Instead, it relies on the communicating devices to be configured with the same baud rate. When receiving a transmission, hardware synchronization mechanisms are used to align the incoming transmission with the receiving device’s peripheral clock.