串口通讯常用代码

 在做通讯程序的设计开发时，常常需要通过串口（COM口）来读写数据，具体的代码实现大致如下：

1. 打开串口

HANDLE h = CreateFile(_T("COM1:"),  // File name

                                            GENERIC_READ | GENERIC_WRITE, // Desire access

                                             0,  //Share mode

                                              NULL, // Security attributes

                                              OPEN_EXISTING, // Create disposition

                                               0, // Flag and attributes

                                                NULL // Template file

                                                );

 

2.清空缓冲区

PurgeComm(h, PURGE_RXCLEAR | PURGE_TXCLEAR | PURGE_RXABORT |PURGE_TXABORT);

3. 串口设置

自定义了一个函数:

static BOOL SerialSetup(HANDLE h, DWORD BaudRate, BYTE ByteSize, BYTE Parity,BYTE StopBits)

{

DCB dcb;

 

if (! GetCommState(h, &dcb)) return FALSE;

switch (BaudRate)

{

case 110: dcb.BaudRate = CBR_110; break;

 case 300: dcb.BaudRate = CBR_300;break;

 case 600: dcb.BaudRate = CBR_600;break;

 case 1200: dcb.BaudRate = CBR_1200;break;

 case 2400: dcb.BaudRate = CBR_2400;break;

 case 4800: dcb.BaudRate = CBR_4800;break;

 case 9600: dcb.BaudRate = CBR_9600;break;

 case 14400: dcb.BaudRate = CBR_14400;break;

 case 19200: dcb.BaudRate = CBR_19200;break;

 case 38400: dcb.BaudRate = CBR_38400;break;

 case 57600: dcb.BaudRate = CBR_57600;break;

 case 115200: dcb.BaudRate = CBR_115200;break;

 case 128000:  dcb.BaudRate = CBR_128000;break;

 case 256000:  dcb.BaudRate = CBR_256000;break;

 default:  dcb.BaudRate = CBR_115200;break;

 }

 dcb.ByteSize = ByteSize;

 dcb.Parity = Parity;

 dcb.StopBits = StopBits;

 dcb.fBinary  = TRUE;

 dcb.fParity  = TRUE;

 dcb.fNull  = FALSE;

 dcb.fOutX  = FALSE;    // disable SW control flow

 dcb.fRtsControl = RTS_CONTROL_DISABLE; // disable HW control flow

 dcb.fDtrControl = DTR_CONTROL_DISABLE;

 dcb.fOutxCtsFlow = FALSE;

 dcb.fOutxDsrFlow = FALSE;

 if( !SetCommState(h, &dcb) )

  return( FALSE );

 if (!GetCommState(h, &dcb))

  return FALSE ;

 EscapeCommFunction(h, SETDTR);

 return TRUE;

}

 

4. 设置事件

SetCommMask(h,EV_RXCHAR);

 

5.超时的设置

 GetCommTimeouts(h, &CommTimeOuts);

 CommTimeOuts.ReadIntervalTimeout = 0;

 CommTimeOuts.ReadTotalTimeoutMultiplier = 0;

 CommTimeOuts.ReadTotalTimeoutConstant = 50;

 CommTimeOuts.WriteTotalTimeoutMultiplier = 0;

 CommTimeOuts.WriteTotalTimeoutConstant = 1000;

 SetCommTimeouts(h, &CommTimeOuts);

6.读取数据

 while(bRunning)

 {

  if(!WaitCommEvent(h, &dwCommEvent, NULL))

   continue;

  if((dwCommEvent&EV_RXCHAR)!=EV_RXCHAR)

   continue;

  bRet = ReadFile(h, (LPVOID)(ReadBuf), sizeof(ReadBuf), &BytesRead, NULL);

  

  dwTemp = GetLastError();

  if(!bRet)

   continue;

  if(BytesRead == 0)

   continue;

。。。。。。。。。。。//处理读到得数据

}

7. 通讯结束

 CloseHandle(h);

 h = NULL;

 bRunning = FALSE;