基于单片机串口通信的上位机和下位机实践串口是计算机上一种非常通用设备通信的协议（不要与通用串行总线Universal Serial Bus或者USB混淆）。

大多数计算机包含两个基于RS232的串口。

串口同时也是仪器仪表设备通用的通信协议；很多GPIB兼容的设备也带有RS-232口。

同时，串口通信协议也可以用于获取远程采集设备的数据。

串口通信的概念非常简单，串口按位（bit）发送和接收字节。

尽管比按字节（byte）的并行通信慢，但是串口可以在使用一根线发送数据的同时用另一根线接收数据。

它很简单并且能够实现远距离通信。

比如IEEE488定义并行通行状态时，规定设备线总常不得超过20米，并且任意两个设备间的长度不得超过2米；而对于串口而言，长度可达1200米。

首先亮出C#的源程序吧。

主要界面：只是作为简单的运用，可以扩展的。

源代码：using System;using System.Collections.Generic;using ponentModel;using System.Data;using System.Drawing;using System.Text;using System.Windows.Forms;using System.IO.Ports;using System.Timers;namespace 单片机功能控制{public partial class Form1 : Form{public Form1(){InitializeComponent();}SerialPort sp = new SerialPort();private void button1_Click(object sender, EventArgs e){String str1 = comboBox1.Text;//串口号String str2 = comboBox2.Text;//波特率String str3 = comboBox3.Text;//校验位String str4 = comboBox5.Text;//停止位String str5 = comboBox4.Text;//数据位Int32 int2 = Convert.ToInt32(str2);//将字符串转为整型Int32 int5 = Convert.ToInt32(str5);//将字符串转为整型groupBox3.Enabled = true;//LED控制界面变可选try{if (button1.Text == "打开串口"){if (str1 == null){MessageBox.Show("请先选择串口！", "Error"); return;}sp.Close();sp = new SerialPort();sp.PortName = comboBox1.Text;//串口编号sp.BaudRate = int2;//波特率switch (str4)//停止位{case "1":sp.StopBits = StopBits.One;break;case "1.5":sp.StopBits = StopBits.OnePointFive;break;case "2":sp.StopBits = StopBits.Two;break;default:MessageBox.Show("Error：参数不正确", "Error");break;}switch (str3){case "NONE":sp.Parity = Parity.None; break;case "ODD":sp.Parity = Parity.Odd; break;case "EVEN":sp.Parity = Parity.Even; break;default:MessageBox.Show("Error：参数不正确", "Error");break;}sp.DataBits = int5;//数据位sp.Parity = Parity.Even;//设置串口属性sp.Open();//打开串口button1.Text = "关闭串口";textBox1.Text = Convert.ToString(sp.PortName) + "已开启！";}else{sp.Close();button1.Text = "打开串口";groupBox3.Enabled = false;//LED控制界面变灰色textBox1.Text = Convert.ToString(sp.PortName) + "已关闭！"; }}catch (Exception er){MessageBox.Show("Error:" + er.Message, "Error");return;}}private void Form1_Load(object sender, EventArgs e){//初始化textBox1.Text = "欢迎使用简易的串口助手！";groupBox3.Enabled = false;//LED控制界面变灰色groupBox6.Enabled = false;groupBox7.Enabled = false;groupBox8.Enabled = false;button3.Enabled = false;button6.Enabled = false;timer1.Start();try{foreach (string in System.IO.Ports.SerialPort.GetPortNames()) //自动获取串行口名称boBox1.Items.Add();//默认设置comboBox1.SelectedIndex = 0;//选择第一个com口comboBox2.SelectedIndex = 4;//波特率4800comboBox3.SelectedIndex = 0;//校验位NONEcomboBox4.SelectedIndex = 0;//停止位为1comboBox5.SelectedIndex = 0;//数据位为8}catch{MessageBox.Show("找不到通讯端口！", "串口调试助手");}}private void timer1_Tick(object sender, EventArgs e){label6.Text = DateTime.Now.ToString();}private void button2_Click(object sender, EventArgs e){try {if (button2.Text == "开启"){groupBox6.Enabled = true;radioButton1.Checked = false;radioButton2.Checked = false;radioButton3.Checked = false;radioButton4.Checked = false;checkBox1.Checked = false;checkBox2.Checked = false;checkBox4.Checked = false;checkBox5.Checked = false;checkBox6.Checked = false;checkBox7.Checked = false;checkBox8.Checked = false;button3.Enabled = true;textBox2.Text = String.Empty;button2.Text = "关闭";}else{groupBox6.Enabled = false;button3.Enabled = false;button2.Text = "开启";textBox2.Text = String.Empty;}}catch (Exception er){MessageBox.Show("Error:" + er.Message, "Error");return;}}private void button3_Click(object sender, EventArgs e){groupBox6.Enabled = true;label7.Text = "已发送";if (textBox2.Text == "")MessageBox.Show("发送失败，请选择发送的数据！");elsesp.WriteLine(textBox2.Text);//往串口写数据}private void checkBox1_CheckedChanged(object sender, EventArgs e) {try {if (checkBox1.Checked){checkBox1.Checked = true;checkBox2.Checked = false;checkBox4.Checked = false;checkBox5.Checked = false;checkBox6.Checked = false;checkBox7.Checked = false;checkBox8.Checked = false;label7.Text = "准备发送";textBox2.Text = "1";}}catch (Exception er){MessageBox.Show("Error:" + er.Message, "Error");return;}}private void checkBox2_CheckedChanged(object sender, EventArgs e) {try {if (checkBox2.Checked){checkBox1.Checked = false;checkBox2.Checked = true;checkBox3.Checked = false;checkBox4.Checked = false;checkBox5.Checked = false;checkBox6.Checked = false;checkBox7.Checked = false;checkBox8.Checked = false;label7.Text = "准备发送";textBox2.Text = "2";radioButton1.Checked = false;radioButton2.Checked = false;radioButton3.Checked = false;radioButton4.Checked = false;}}catch (Exception er){MessageBox.Show("Error:" + er.Message, "Error");return;}}private void checkBox3_CheckedChanged(object sender, EventArgs e) {try{if (checkBox3.Checked){checkBox1.Checked = false;checkBox2.Checked = false;checkBox3.Checked = true;checkBox4.Checked = false;checkBox5.Checked = false;checkBox6.Checked = false;checkBox7.Checked = false;checkBox8.Checked = false;radioButton1.Checked = false;radioButton2.Checked = false;radioButton3.Checked = false;radioButton4.Checked = false;label7.Text = "准备发送";textBox2.Text = "3";}}catch (Exception er){MessageBox.Show("Error:" + er.Message, "Error");return;}}private void checkBox4_CheckedChanged(object sender, EventArgs e) {try{if (checkBox4.Checked){checkBox1.Checked = false;checkBox2.Checked = false;checkBox3.Checked = false;checkBox4.Checked = true;checkBox5.Checked = false;checkBox6.Checked = false;checkBox7.Checked = false;checkBox8.Checked = false;radioButton1.Checked = false;radioButton2.Checked = false;radioButton3.Checked = false;radioButton4.Checked = false;label7.Text = "准备发送";textBox2.Text = "4";}}catch (Exception er){MessageBox.Show("Error:" + er.Message, "Error");return;}}private void checkBox5_CheckedChanged(object sender, EventArgs e) {try{if (checkBox5.Checked){checkBox1.Checked = false;checkBox2.Checked = false;checkBox3.Checked = false;checkBox4.Checked = false;checkBox5.Checked = true;checkBox6.Checked = false;checkBox7.Checked = false;checkBox8.Checked = false;radioButton1.Checked = false;radioButton2.Checked = false;radioButton3.Checked = false;radioButton4.Checked = false;label7.Text = "准备发送";textBox2.Text = "5";}}catch (Exception er){MessageBox.Show("Error:" + er.Message, "Error");return;}}private void checkBox6_CheckedChanged(object sender, EventArgs e) {try{if (checkBox6.Checked){checkBox1.Checked = false;checkBox2.Checked = false;checkBox3.Checked = false;checkBox4.Checked = false;checkBox5.Checked = false;checkBox6.Checked = true;checkBox7.Checked = false;checkBox8.Checked = false;radioButton1.Checked = false;radioButton2.Checked = false;radioButton3.Checked = false;radioButton4.Checked = false;label7.Text = "准备发送";textBox2.Text = "6";}}catch (Exception er){MessageBox.Show("Error:" + er.Message, "Error");return;}}private void checkBox7_CheckedChanged(object sender, EventArgs e) {try{if (checkBox7.Checked){checkBox1.Checked = false;checkBox2.Checked = false;checkBox3.Checked = false;checkBox4.Checked = false;checkBox5.Checked = false;checkBox6.Checked = false;checkBox7.Checked = true;checkBox8.Checked = false;radioButton1.Checked = false;radioButton2.Checked = false;radioButton3.Checked = false;radioButton4.Checked = false;label7.Text = "准备发送";textBox2.Text = "7";}}catch (Exception er){MessageBox.Show("Error:" + er.Message, "Error");return;}}private void checkBox8_CheckedChanged(object sender, EventArgs e) {try{if (checkBox8.Checked){checkBox1.Checked = false;checkBox2.Checked = false;checkBox3.Checked = false;checkBox4.Checked = false;checkBox5.Checked = false;checkBox6.Checked = false;checkBox7.Checked = false;checkBox8.Checked = true;radioButton1.Checked = false;radioButton2.Checked = false;radioButton3.Checked = false;radioButton4.Checked = false;label7.Text = "准备发送";textBox2.Text = "8";}}catch (Exception er){MessageBox.Show("Error:" + er.Message, "Error");return;}}private void button5_Click(object sender, EventArgs e) {try{if (button5.Text == "开启"){radioButton1.Checked = false;radioButton2.Checked = false;radioButton3.Checked = false;radioButton4.Checked = false;checkBox1.Checked = false;checkBox2.Checked = false;checkBox3.Checked = false;checkBox4.Checked = false;checkBox5.Checked = false;checkBox6.Checked = false;checkBox7.Checked = false;checkBox8.Checked = false;groupBox7.Enabled = true;button6.Enabled = true;textBox2.Text = String.Empty;button5.Text = "关闭";}else{groupBox7.Enabled = false;button6.Enabled = false;button5.Text = "开启";textBox2.Text = String.Empty;}}catch (Exception er){MessageBox.Show("Error:" + er.Message, "Error"); return;}}private void button6_Click(object sender, EventArgs e) {label7.Text = "已发送";if (textBox2.Text == "")MessageBox.Show("发送失败。