Table of contents title

describe
Precautions
underlying implementation
Example
Implemented in c language
Conclusion

Shell command column: Full analysis of Linux Shell commands

describe

minicom is a command line tool for serial communication in Linux. It provides an interactive terminal interface that can communicate with other devices through the serial port, such as debugging serial devices, routers, embedded systems, etc.

Using the minicom command, you can achieve the following functions:

Serial communication: minicom can communicate with other devices through the serial port, and data can be sent and received through the serial port terminal.
Debugging serial port devices: minicom can be used to debug serial port devices, such as debugging serial port communication problems in embedded systems or other devices. It can open a serial port terminal, send instructions or data, and view the data returned by the device for troubleshooting and debugging.
Remote maintenance: minicom can connect to remote devices, such as routers, switches, etc., through the serial port for remote maintenance and management. Through the serial port terminal, you can execute commands, configure devices, view logs and other operations.
File transfer: minicom also supports file transfer through the serial port. You can use minicom's file transfer feature to send files from your computer to other devices, or to receive files from your device to your computer.

In short, minicom is a powerful serial communication tool that is widely used in serial communication, debugging, remote maintenance and other scenarios in Linux systems. It provides an interactive terminal interface to facilitate users to communicate and operate with other devices.

Syntax format

minicom [options] [configuration]

Parameter Description

-D, --device <device>:Specify the serial device to be connected, for example /dev/ttyUSB0.
-b, --baudrate <baudrate>:Set the baud rate, for example 9600.
-8, --eightbits:Set the data bits to 8 bits.
-1, --onestopbits:Set the stop bit to 1 bit.
-p, --parity <parity>: Set the parity bit, the optional values are none, even, odd.
-s, --flow-control <flowcontrol>: Set flow control, optional values are none, software, hardware.
-C, --capturefile <filename>: Save the terminal session to the specified file.
-l, --noinit: Do not execute the minicom initialization script.
-m, --macro <macrofile>: Execute the specified macro file.
-v, --version: Display minicom version information.
-h, --help: Display minicom help information.

error condition

If the specified serial port device does not exist or cannot be accessed, an error message will be reported indicating that the device cannot be found.
If the specified baud rate does not match the device, communication may fail.
If the specified parity bits do not match the device, communication errors may result.
If the specified data bits, stop bits, or flow control settings are incorrect, communication abnormalities may occur.
If the minicom initialization script fails to execute, the terminal may not work properly.
If the specified macro file does not exist or cannot be accessed, an error message will be displayed indicating that the file cannot be found.
If you do not have sufficient permissions to access the serial device, you may not be able to open the terminal.

Please note that the above only lists some common error conditions, and other errors may be encountered in actual use. When using the minicom command, it is recommended to carefully consult the relevant documentation and reference materials to learn more parameters and error handling methods.

Precautions

There are some things to note when using the minicom command:

Permissions: Using the minicom command requires sufficient permissions to access the serial device. Normally, only root users or users with serial port access can use the minicom command. If you do not have sufficient permissions, you can use the sudo command to elevate your permissions.
Serial device name: When using the minicom command, you need to specify the correct serial device name. You can use ls /dev/tty*the command to view the list of serial devices in the system. Common serial port device names include /dev/ttyS0, /dev/ttyS1, /dev/ttyUSB0etc.
Baud rate and other parameters: When using the minicom command to connect to a serial device, you need to ensure that the specified baud rate, data bits, stop bits, parity bits and other parameters match the configuration of the device. If parameters are set incorrectly, communication failure or data errors may result.
Exit minicom: After using the minicom command to connect to the serial device, you can exit minicom by pressing Ctrl+A and then pressing X. If you close the terminal window directly, the minicom process may still be running in the background, and you need to end the process manually.
Terminal settings: In the minicom terminal interface, you can open the terminal settings menu by pressing Ctrl+A and then pressing Z. Terminal settings can be performed in the menu, such as modifying parameters such as baud rate, data bits, stop bits, parity bits, and saving and loading configuration files.
File transfer: The minicom command also supports file transfer through the serial port. When performing file transfer, you need to ensure that the settings of both ends of sending and receiving files are correct, and that the minicom command parameters and configurations of both ends match.
Macro files: The minicom command supports the execution of macro files, and a series of commands and operations can be defined in the macro files. When using a macro file, you need to ensure that the path and name of the macro file are correct and that the file content conforms to minicom's macro file format.

In short, when using the minicom command, you need to read the relevant documents and reference materials carefully to understand the usage and precautions of the command. At the same time, the parameters and configuration of minicom should be appropriately adjusted according to specific usage scenarios and needs to ensure normal serial communication and operation.

underlying implementation

The minicom command is a command line tool based on serial port communication. Its underlying implementation mainly relies on the serial port device driver and serial port communication protocol provided by the Linux system.

In Linux systems, serial port devices usually correspond to /dev/tty*files, such as /dev/ttyS0, /dev/ttyS1, /dev/ttyUSB0etc. The minicom command communicates with the device by opening the specified serial device file.

The underlying serial device driver used by the minicom command is provided by the Linux kernel, which is responsible for underlying communication with hardware devices. The serial device driver implements data sending and receiving by interacting with the device's serial port controller.

During the data transmission process, the minicom command follows the serial communication protocol, including the settings of parameters such as baud rate, data bits, stop bits, and parity bits. These parameters are specified in the minicom command through command line parameters or configuration files.

The minicom command realizes data exchange with the device by calling the underlying serial device driver interface. It can send instructions or data to the device and receive data returned by the device. The minicom command provides an interactive terminal interface. Users can enter instructions or data in the terminal interface and view the data returned by the device.

In addition to basic serial communication functions, the minicom command also provides some additional functions, such as file transfer, macro file execution, etc. These functions are implemented through the implementation of the minicom command itself and have no direct relationship with the underlying serial device driver and communication protocol.

In short, the underlying implementation of the minicom command relies on the serial device driver and serial communication protocol provided by the Linux system. It implements serial communication and other functions by calling the underlying driver interface to exchange data with the device.

Example

Example 1

Use minicom to connect to the serial device:

1. 打开终端
2. 输入命令：minicom -D /dev/ttyUSB0
3. 按下回车键，进入minicom终端界面
4. 可以在终端界面中发送和接收数据
5. 按下Ctrl+A，再按下X，退出minicom

Example 2

Use minicom to debug embedded devices:

1. 打开终端
2. 输入命令：minicom -D /dev/ttyS0
3. 按下回车键，进入minicom终端界面
4. 在终端界面中发送指令或数据，查看设备返回的数据
5. 按下Ctrl+A，再按下X，退出minicom

Example three

Use minicom to remotely maintain your router:

1. 打开终端
2. 输入命令：minicom -D /dev/ttyUSB1
3. 按下回车键，进入minicom终端界面
4. 登录路由器，执行命令进行配置或管理操作
5. 按下Ctrl+A，再按下X，退出minicom

Example 4

Using minicom for file transfer:

1. 打开终端
2. 输入命令：minicom -D /dev/ttyS1
3. 按下回车键，进入minicom终端界面
4. 进入文件传输模式，发送或接收文件
5. 按下Ctrl+A，再按下X，退出minicom

Example five

Use minicom for serial port debugging and log viewing:

1. 打开终端
2. 输入命令：minicom -D /dev/ttyUSB0
3. 按下回车键，进入minicom终端界面
4. 发送调试指令，查看设备返回的调试信息
5. 按下Ctrl+A，再按下X，退出minicom

Example 6

Use minicom to connect to the serial port of the embedded system:

1. 打开终端
2. 输入命令：minicom -D /dev/ttyS2
3. 按下回车键，进入minicom终端界面
4. 在终端界面中与嵌入式系统进行交互
5. 按下Ctrl+A，再按下X，退出minicom

Example 7

Use minicom for serial communication testing:

1. 打开终端
2. 输入命令：minicom -D /dev/ttyUSB0
3. 按下回车键，进入minicom终端界面
4. 在终端界面中发送数据，查看是否能够正常接收
5. 按下Ctrl+A，再按下X，退出minicom

Implemented in c language

The following is a simple example that demonstrates how to use C language code to implement a simplified version of the minicom command. Please note that this is just a basic example, the actual minicom command implementation is more complex and complete.

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <termios.h>
#include <unistd.h>

int main() {
    
    
    int fd;
    struct termios options;

    // 打开串口设备
    fd = open("/dev/ttyUSB0", O_RDWR | O_NOCTTY | O_NDELAY);
    if (fd == -1) {
    
    
        perror("无法打开串口设备");
        return -1;
    }

    // 配置串口参数
    tcgetattr(fd, &options);
    cfsetispeed(&options, B9600);  // 设置波特率为9600
    cfsetospeed(&options, B9600);
    options.c_cflag |= (CLOCAL | CREAD);  // 忽略调制解调器线路状态，允许接收数据
    options.c_cflag &= ~PARENB;  // 禁用奇偶校验
    options.c_cflag &= ~CSTOPB;  // 设置停止位为1位
    options.c_cflag &= ~CSIZE;  // 清除数据位设置
    options.c_cflag |= CS8;  // 设置数据位为8位
    tcsetattr(fd, TCSANOW, &options);

    // 读取和发送数据
    char buffer[255];
    int n;
    while (1) {
    
    
        // 从终端读取输入数据
        n = read(STDIN_FILENO, buffer, sizeof(buffer));
        if (n > 0) {
    
    
            // 将数据发送到串口设备
            write(fd, buffer, n);
        }

        // 从串口设备读取数据并显示到终端
        n = read(fd, buffer, sizeof(buffer));
        if (n > 0) {
    
    
            write(STDOUT_FILENO, buffer, n);
        }
    }

    // 关闭串口设备
    close(fd);

    return 0;
}

This example uses the header files and functions provided by the Linux system to implement serial communication. First, opena serial port device file is opened through a function. Then, use the tcgetattrand tcsetattrfunctions to configure the serial port parameters, such as baud rate, data bits, stop bits, etc. Next, use reada function to read the input data from the terminal and writea function to send the data to the serial device. At the same time, use readfunctions to read data from the serial device and use writefunctions to display the data to the terminal.

Please note that this is just a simple example, actual minicom command implementation has many more features and error handling to consider. In addition, different operating systems and platforms may have different serial device drivers and APIs, so the actual implementation may vary.

Conclusion

During our exploration, we have gained an in-depth understanding of the power and wide application of Shell commands. However, learning these techniques is just the beginning. The real power comes from how you integrate them into your daily routine to increase efficiency and productivity.

心理学告诉我们，学习是一个持续且积极参与的过程。所以，我鼓励你不仅要阅读和理解这些命令，还要动手实践它们。尝试创建自己的命令，逐步掌握Shell编程，使其成为你日常工作的一部分。

同时，请记住分享是学习过程中非常重要的一环。如果你发现本博客对你有帮助，请不吝点赞并留下评论。分享你自己在使用Shell命令时遇到的问题或者有趣的经验，可以帮助更多人从中学习。
此外，我也欢迎你收藏本博客，并随时回来查阅。因为复习和反复实践也是巩固知识、提高技能的关键。

最后，请记住：每个人都可以通过持续学习和实践成为Shell编程专家。我期待看到你在这个旅途中取得更大进步！

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[Shell command collection network communication] Linux serial communication minicom command usage guide