C# 28.实现串口空闲中断接收功能

CH340：ReadTimeout需设置到80ms，才稳定
FT232：ReadTimeout设置在3ms，很稳定

结论：使用该方法，FT232的设备较好。

using System.Threading;        
//中断接收线程
Thread threadIntRx = null;
//串口接收缓存大小
private const int rxBufNum = 20000;
private int RxCnt = 0; //接收字节计数, 作用相当于全局变量
private byte[] RxBuf = new byte[rxBufNum];
private const ushort RX_FRAME_MAX = 2000;

public Form1()
{
     //串口接收中断
     serialPort1.ReadTimeout = 30;
     threadIntRx = new Thread(new ThreadStart(ThreadReceive));
     threadIntRx.Start();
}

 //串口空闲中断接收
 void ThreadReceive()
 {
     while (true)
     {
         if (serialPort1.IsOpen)
         {
             try
             {
                 int cnt = serialPort1.BytesToRead;      //获取接收缓冲区中的字节数
                 if (cnt > 0)     //缓存中有数据，先一次行读完
                 {
                     double length = cnt + RxCnt;
                     if (length <= RX_FRAME_MAX)
                     {
                         serialPort1.Read(RxBuf, RxCnt, cnt);
                         RxCnt += cnt;
                     }
                     else
                     {
                         serialPort1.DiscardInBuffer();      //清空接收缓存
                         RxCnt = 0;
                     }
                 }
                 byte data = (byte)serialPort1.ReadByte();
                 RxBuf[RxCnt++] = data;
             }
             catch       //30ms超时
             {
                 if(RxCnt >= 12)
                 {
                     Invoke((EventHandler)(delegate
                     {
                         CmdParse(RxBuf, RxCnt);
                     }));  
                 }                
                 RxCnt = 0;
             }
         }
         else
         {
             System.Threading.Thread.Sleep(200);
         }
     }
 }