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Sending and receiving of C serialport

2022-07-26 09:10:00 【InfoQ】

Preface ：

Last time, the blogger explained the serial port control Serialport Configuration of , In this issue, I will explain Serialport Send and receive of , This SerialPort The control of serial communication provides the communication between host computer and MCU , There are many ways , It can be convenient for everyone to use , It's also easy to use .

Once a day , Prevent puppy love ：

1.SerialPort Serial port control sending configuration

1.1 Take the project of the last article , I set up the children's shoes on the basis of that project. You can see the previous article of the blogger , We need to set up the interface first , Send box , Receiving frame , Send button

1.2 So let's see serialPort Send several interfaces it provides ：

public void Write(byte[] buffer, int offset, int count);
  Writes a specified number of bytes to the serial port using the data in the buffer .
 // buffer:  An array of bytes containing the data to be written to the port .
 // offset: buffer  Zero based byte offset in parameter , Start copying bytes to port... From here .
 // count:  Number of bytes to write .
public void Write(string text);
  Writes the specified string to the serial port .
 text:  Output string .
public void Write(char[] buffer, int offset, int count);
  Writes a specified number of characters to the serial port using the data in the buffer .
 // buffer:  The character array containing the data to be written to the port .
 // offset: buffer  Zero based byte offset in parameter , Start copying bytes to port... From here .
 // count:  The number of characters to write .
public void WriteLine(string text);
 //  The specified string and  System.IO.Ports.SerialPort.NewLine  Write value to output buffer .
 // text:  The string to write to the output buffer .

3 Double click the send button to automatically generate the method function , Write the method we sent ：

1.4 The code is as follows ： It can be used directly , The premise is that your interface is the same as that of the blogger , Note whether the interface controls correspond to the blogger function trigger , Not to change the trigger of the interface , Refer to the previous article for details .

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO.Ports;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Serilport
{
 public partial class Form1 : Form
 {
 public Form1()
 {
 InitializeComponent();
 System.Windows.Forms.Control.CheckForIllegalCrossThreadCalls = false;
 }
 private void SearchAndAddSerialToComboBox(object sender, EventArgs e)
 {
 string Buffer;
 comboBox1.Items.Clear(); // Records scanned before the beginning of the Qing Dynasty 
 for (int i = 0; i < 20; i++)
 {
 try
 {
 Buffer = &quot;COM&quot; + i.ToString(); // get COM1-20
 serialPort1.PortName = Buffer; // obtain COM Information 
 serialPort1.Open(); // Open the serial port 
 comboBox1.Items.Add(Buffer);
 comboBox1.Text = Buffer; // Add serial port to get recordset 
 serialPort1.Close(); // Turn off the serial port 
 }
 catch { }
 }
 }

 private void button4_Click(object sender, EventArgs e)
 {
 try
 {
 serialPort1.PortName = comboBox1.Text;
 serialPort1.BaudRate = Convert.ToInt32(comboBox2.Text, 10);
 serialPort1.DataBits = Convert.ToInt32(comboBox3.Text, 10);
 if (comboBox4.Text == &quot;None&quot;) { serialPort1.Parity = Parity.None; }
 else if (comboBox4.Text == &quot; Odd check &quot;) { serialPort1.Parity = Parity.Odd; }
 else if (comboBox4.Text == &quot; Even check &quot;) { serialPort1.Parity = Parity.Even; }
 else if (comboBox4.Text == &quot;Mark&quot;) { serialPort1.Parity = Parity.Mark; }
 else if (comboBox4.Text == &quot; Space check &quot;) { serialPort1.Parity = Parity.Space; }
 if (comboBox5.Text == &quot;1&quot;)
 {
 serialPort1.StopBits = StopBits.One;
 }
 else if (comboBox5.Text == &quot;1.5&quot;)
 {
 serialPort1.StopBits = StopBits.OnePointFive;
 }
 else if (comboBox5.Text == &quot;1.5&quot;)
 {
 serialPort1.StopBits = StopBits.Two;
 }
 //serialPort1.ReadTimeout(2000);
 serialPort1.Open();
 button2.Enabled = false;// The open serial port button is not available 
 //button3.Enabled = true;// Turn off the serial port 
 }
 catch
 {
 MessageBox.Show(&quot; Port error , Please check the serial port &quot;, &quot; error &quot;);
 }
 }

 private void button1_Click(object sender, EventArgs e)
 {
 string str = textBox2.Text;// Get the data of the sending box 
 byte[] Data = new byte[1];// As a container for sending 
 if (serialPort1.IsOpen)// Judge whether our serial port is open 
 {
 for (int j = 0; j < str.Length; j++)// Traverse our send statement , Bloggers now send one by one 
 {
 if (str[j] == ' ')// Our send statements are separated by spaces , We're going to traverse 
 {
 continue;
 }
 else
 {
 try
 {
 Data[0] = Convert.ToByte(str.Substring(j, 2), 16);//substring It's from j The location of the take str character string 2 Bytes ,16 Hexadecimal number 
 }
 catch
 {
 MessageBox.Show(&quot; Please check the hexadecimal data format error &quot;);
 }
 try
 {
 serialPort1.Write(Data, 0, 1);// This means sending ,data data , from 0 The position begins , Take a value .
 j++;
 }
 catch
 {
 MessageBox.Show(&quot; Port send failed , The system will close the current serial port error &quot;);
 serialPort1.Close();// Turn off the serial port 
 }
 }

 }
 }
 }
 }
}

2.SarilPort Serial port control receiving configuration

2.1 In understanding SerialPort Interface of receiving method

public int Read(char[] buffer, int offset, int count);
  from  System.IO.Ports.SerialPort  Read some characters from the input buffer , These characters are then written to the character array at the specified offset .
 // buffer:  An array of bytes into which input is written .
 // offset:  The number of bytes to write  buffer  Offset in .
 // count:  The maximum number of bytes read .  If  count  Greater than the number of bytes in the input buffer , Read fewer bytes .
public int Read(byte[] buffer, int offset, int count);
  from  System.IO.Ports.SerialPort  The input buffer reads some bytes and writes those bytes to the offset specified in the byte array .
 // buffer:  An array of bytes into which input is written .
 // offset: The number of bytes to write  buffer  Offset in .
 // count: The maximum number of bytes read .  If  count  Greater than the number of bytes in the input buffer , Read fewer bytes .
public int ReadByte();
  from  System.IO.Ports.SerialPort  A byte is synchronously read from the input buffer .
public int ReadChar();
  from  System.IO.Ports.SerialPort  Read a character synchronously from the input buffer .
public string ReadExisting();
  On the basis of coding , Read  System.IO.Ports.SerialPort  Object and all immediately available bytes in the input buffer .
public string ReadLine();
  Read all the way to... In the input buffer  System.IO.Ports.SerialPort.NewLine  value .
public string ReadTo(string value);
  Read until the specified... In the input buffer  value  String .
 value:  A value indicating the stop position of the read operation .

2.2, Create the receiving function according to the screenshot ,SerialPort Automatically receive data

2.3 If you don't want to use loops , Data can be read out at one time , So it won't be so troublesome , Read its own interface carefully , Find your own interface , I'll send my code to you for reference ：

private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
 {
 byte data = 0;
 int len = 0;
 int bufsize = (int)serialPort1.BytesToRead;// Get the number of cache bytes 
 while (len < bufsize)// Get one after another 
 {
 data = (byte)serialPort1.ReadByte();// Get the value of the serial port , You can also use read The whole method is not read one by one 
 len++;
 string str = Convert.ToString(data, 16).ToUpper();// After obtaining it, we will TextBox Medium output 
 if (str.Length == 1)// If the value we get is a bit, we fill in the front 0
 {
 textBox1.AppendText(&quot; 0&quot; + str);
 }
 else
 {
 textBox1.AppendText(&quot; &quot; + str);// The two values are separated by a space in front  
 }
 } 
 textBox1.AppendText(System.Environment.NewLine);// Line break 
 serialPort1.DiscardInBuffer();// Clear the previous cache 

 }

3. show ,SerialPort Send and receive , Blogger here happens to have a single chip microcomputer , Let me show you , If you're interested in this , Virtual serial port can also be used , Simulate and play .

notes ： Bloggers report a thread error when running C# abnormal : Has triggered : " Invalid inter thread operation : Never create controls “textBox1” Thread access it ." (System.InvalidOperationException), Need to be in Form1 Add code inside

System.Windows.Forms.Control.CheckForIllegalCrossThreadCalls = false;

Disable capturing calls to the wrong thread .

summary ：

The blogger just briefly introduced ,C# SerialPort Sending and receiving of serial port control , And demonstrated , Students interested in this aspect can learn , Bloggers are just beginners , I learned it because I was working on a project recently , learn C# Very few students , I hope you don't like it , It's not easy to create , give the thumbs-up , Focus on , Comments .