Serial Communication is a method of data exchange between a computer and external devices or computers.

Serial communication technology is to transmit data bit by bit in sequence, and only two data transmission lines are needed. Compared with parallel communication, although serial communication technology saves port consumption, it also reduces the data transmission rate.

Serial communication classification

The communication direction of serial communication is generally divided into three categories:

Simplex: only allows data to be transmitted in one direction;

Half-duplex: data can be received and sent, but only one direction of data transmission is allowed at the same time;

Full duplex: Data can be received and sent, and data can be transmitted in both directions at the same time.

There are two serial communication methods, namely synchronous communication and asynchronous communication. Synchronous communication can be understood as that the two parties in communication are controlled by the same clock line and perform synchronous data transmission. Common synchronous communication methods include I2C, SPI, etc.; 

asynchronous communication does not require a clock synchronization signal, and the sending device and the receiving device each select their own clock control to realize data transmission and reception. Common asynchronous communication includes UART, RS232, etc.

Comparison of synchronous and asynchronous communication

In serial communication, the main differences and advantages and disadvantages of synchronous and asynchronous communication are as follows:

1. In synchronous communication, the clocks of the sender and receiver are unified, which also makes there be no interval between characters during data transmission. However, asynchronous communication is different. The sender and receiver do not require clock synchronization, which means that characters are transmitted asynchronously;

2. In fact, the transmission objects of synchronous communication and asynchronous communication are different. Asynchronous communication is character-oriented transmission, and the unit is character. Synchronous communication is oriented to bit transmission, and the unit is frame;

3. Asynchronous Single serial port server is different from synchronous transmission, and requires a specific clock line to coordinate timing;

4. In general, the rate of synchronous communication is higher than that of asynchronous communication.

How to choose serial communication?

When choosing serial communication, there are many factors that need to be considered to ensure the effectiveness and reliability of communication. Here are some key factors to consider when choosing serial communication:

1. Communication protocol: First determine the protocol used for communication between the two parties, such as RS-232, RS-485, RS-422, etc. These protocols differ in electrical characteristics, communication distance, anti-interference capabilities, etc. For example, RS-232 is suitable for short-distance communication, while RS-485 is suitable for long-distance and multi-point communication.

2. Baud rate: The baud rate defines the speed of serial communication, that is, the number of bits transmitted per second. Choosing an appropriate baud rate can ensure the stability and accuracy of data transmission. The selection of the baud rate needs to consider factors such as the communication distance, the size and urgency of the data being transmitted.

3. Data bits, stop bits and parity bits: These parameters define the structure of the data packet. The data bits are usually 7 or 8 bits, the stop bits can be 1 or 2 bits, and the parity bit is used to detect whether errors occur during data transmission, which can be odd parity, even parity or no parity. These parameters need to be consistent between both devices.

4. Interface type: Consider the interface type supported by the device. Modern devices may support different interface types such as USB to serial port, Bluetooth serial port, etc. Choose according to actual needs and device compatibility.

5. Software support: Make sure your operating system and application software support the selected serial communication protocol and parameters. Some systems or software may require additional drivers or configuration to enable serial communication.

6. Anti-interference ability: In an environment with strong electromagnetic interference, it is very important to choose communication protocols and hardware devices with strong anti-interference ability.

7. Cost and Availability: Consider project budget and equipment availability. Sometimes cost and availability may influence the final choice.

When choosing serial communication, it is recommended to read the device manual in detail to understand the specific requirements and restrictions of the device. If necessary, you can consult the device manufacturer or professionals. In addition, actually testing the communication configuration is an important step to ensure stable communication.