c#通过串⼝及CAN模块实现上位及下位机通讯⽬录前⾔⼀、串⼝、CAN总线⼆、使⽤步骤1.RS232串⼝通讯（指令下发与接收）2.CAN总线通讯总结前⾔学习及⼯作中我们经常会遇到上位机与下位机通讯等⼯作，结合场景使⽤不同的通讯⽅式实时通讯，以下为⼯作中遇到的上位机与下位机进⾏实时通讯，采⽤RS232串⼝和CAN总线形式进⾏⽹络通讯。
⼀、串⼝、CAN总线串⾏接⼝简称串⼝，也称串⾏通讯接⼝或串⾏通讯接⼝（通常指设备的COM接⼝），是采⽤串⾏通信⽅式的扩展接⼝。
串⾏接⼝（Serial Interface）是指数据⼀位⼀位地顺序传送。
其特点是通讯简单，只要⼀对传输线，通过设备设置传输线端⼝等参数就可以实现双向通信，从⽽⼤⼤降低了成本，特别适⽤于远距离通信，但传送速度较慢。
CAN是控制器局域⽹络(Controller Area Network, CAN)的简称，是由以研发和⽣产汽车电⼦产品著称的德国BOSCH公司开发的，并最终成为国际标准（ISO 11898），是国际上应⽤最⼴泛的现场总线之⼀。
在北美和西欧，CAN总线协议已经成为汽车计算机控制系统和嵌⼊式⼯业控制局域⽹的标准总线，并且拥有以CAN为底层协议专为⼤型货车和重⼯机械车辆设计的J1939协议。
上位机与与下位机制定好通⽤协议通过CAN模块将数据进⾏16进制转换实时通讯。
⼆、使⽤步骤1.RS232串⼝通讯（指令下发与接收）代码如下（⽰例）：//命名空间引⼊using System.IO.Ports;public SerialPort serialPort;//定义串⼝对象类public//定义连接⽅法public void Connect(){serialPort = new SerialPort();serialPort.BaudRate = 1200;//波特率serialPort.PortName = "COM1";serialPort.Parity = Parity.None;//校验法：⽆serialPort.DataBits = 8;//数据位：8serialPort.StopBits = StopBits.One;//停⽌位：1try{serialPort.Open();//打开串⼝serialPort.DtrEnable = true;//设置DTR为⾼电平serialPort.RtsEnable = true;//设置RTS位⾼电平serialPort.DataReceived += new SerialDataReceivedEventHandler(serialPort_DataReceived);//DataReceived事件委托byte[] WriteBuffer = Encoding.ASCII.GetBytes("下发指令");//下发serialPort.Write(WriteBuffer, 0, WriteBuffer.Length);}catch (Exception ex){//打开串⼝出错，显⽰错误信息Console.WriteLine("串⼝打开失败");}}2.CAN总线通讯代码如下（⽰例）：//⾸先与CAN模块进⾏连接public TcpClient mTcp = new TcpClient();private const int READ_BUFFER_SIZE = 1000;private byte[] readBuffer = new byte[READ_BUFFER_SIZE + 1];public delegate void DoReadEventHandle(object sender, string e);public event DoReadEventHandle ReadedEvent;public event DoReadEventHandle LogEvent;public string recStr { get; set; }public string HandString { get; set; }public bool Connect(){//Can模块ipstring mIPAddress = "192.168.1.1";IPAddress hostIPAddress = IPAddress.Parse(mIPAddress);//端⼝int mPort = 8080;IPEndPoint endIP = new IPEndPoint(hostIPAddress, mPort);try{mTcp = new TcpClient(mIPAddress, mPort);DateTime Savetime = DateTime.Now;TimeSpan n = new TimeSpan();while (true){n = DateTime.Now - Savetime;if (n.TotalMilliseconds > 1000 || mTcp.Client.Connected) break;}if (!mTcp.Client.Connected) return false;mTcp.GetStream().BeginRead(readBuffer, 0, READ_BUFFER_SIZE, DoRead, null);}catch (Exception){return false;}return true;}private void DoRead(IAsyncResult ar){try{int BytesRead = mTcp.GetStream().EndRead(ar);if (BytesRead > 0){string s = "";for (int i = 0; i <= BytesRead - 1; i++){s = s + string.Format("{0:x2}", readBuffer[i]) + " ";}Console.WriteLine(s);var t = s.Split(new string[] { "aa 00 ff 00 00 00 00 00 00 00 00 00 55" }, StringSplitOptions.RemoveEmptyEntries).FirstOrDefault(ex => ex != " ");if (!string.IsNullOrEmpty(t)){recStr += t + "\r\n";if (HandString == recStr && LogEvent != null){HandString = null;LogEvent(this, "握⼿成功！");}} mTcp.GetStream().BeginRead(readBuffer, 0, READ_BUFFER_SIZE, DoRead, null);}}catch (Exception e){mTcp.Client.Close();}}//数据发送public void sendCan(string temperature, bool check){HandString = "0xC0 0x02 0x02 0x00 0x00";string[] tmp = temperature.Split(' ');var buf = new byte[22];for (int i = 0; i < buf.Length; i++){buf[i] = 0;}for (int i = 0; i < tmp.Length; i++){try{buf[i] = Convert.ToByte(tmp[i], 16);}catch (Exception e){buf[i] = 0;}}SendData(buf, 0, 13, check);}public bool SendData(byte[] sendBytes, int mStart, int mLen, bool check = true) {if (!check) return false;try{lock (mTcp.GetStream()){mTcp.GetStream().Write(sendBytes, mStart, mLen);}return true;}catch (Exception x){return false;}}总结1、RS232串⼝通讯接⼝的信号电平值较⾼，易损坏接⼝电路的芯⽚，传输速率较低，传输距离有限。
