UART serial communication is a widely used asynchronous serial communication method in embedded systems, industrial control, and device interconnection. Here are its core points:
Basic Concept
UART: The full name is Universal Asynchronous Receiver/Transmitter, which is a hardware circuit module responsible for converting parallel data into serial data for transmission, or converting serial data into parallel data for reception.
Communication Characteristics: Asynchronous communication does not require clock signal synchronization; full-duplex communication is achieved through two lines (TX for transmission and RX for reception) for bidirectional data transfer.
Data Frame Format
Start Bit: 1 bit low level (logic 0), indicating the start of the data frame and triggering the receiver to prepare for reception.
Data Bits: 5-9 bits (commonly 8 bits), the actual binary data transmitted, sent in the order of least significant bit first and most significant bit last.
Parity Bit: Optional, 1 bit parity bit used to detect data transmission errors. Odd parity requires the total number of ‘1’s in the data bits and parity bit to be odd, while even parity requires it to be even.
Stop Bits: 1-2 bits high level (logic 1), indicating the end of the data frame, providing the receiver with buffer time to prevent data frame overlap.
Baud Rate: Indicates the data transmission rate, measured in bps (bits per second), such as 9600 bps, 115200 bps, etc. Both transmitting and receiving parties must set the same baud rate to ensure data synchronization.
Communication Process
Sender: Converts parallel data into serial data and sends it in the order of start bit, data bits, optional parity bit, and stop bits.
Receiver: After detecting the start bit, samples the data bits at the agreed baud rate. After receiving the complete data frame, it removes the start bit, parity bit, and stop bits, converting the serial data back into parallel data for system processing.
Application Scenarios
Device debugging in embedded development (e.g., communication between microcontrollers and PCs).
Data transmission between sensors and controllers in industrial control.
Communication between peripherals such as Bluetooth modules, GPS modules, and serial screens with the host.
UART serial communication has become a common communication method in embedded systems and device interconnection due to its simplicity, low cost, and high reliability. In practical applications, attention must be paid to baud rate matching, data format configuration, and electrical connection specifications to ensure stable and reliable communication.