windows串口通讯异步与同步API如何设置？

csdn一绝 2017-08-09 05:32:35



m_hCom = CreateFile(com, GENERIC_READ | GENERIC_WRITE, /*FILE_SHARE_WRITE|FILE_SHARE_READ*/0, NULL, OPEN_EXISTING, /*FILE_FLAG_OVERLAPPED*/0, NULL);  //FILE_SHARE_WRITE|FILE_SHARE_READ

	if (m_hCom == INVALID_HANDLE_VALUE)

	{

		int a = GetLastError();

		CString errStr;

		errStr.Format("open failed! error code is:%d\n",a);

	    AfxMessageBox(errStr);

		return FALSE;

	}

	//设置读超时

	COMMTIMEOUTS timeouts;

	GetCommTimeouts(m_hCom, &timeouts);

	timeouts.ReadIntervalTimeout = MAXDWORD;           //2017/8/8 added

	timeouts.ReadTotalTimeoutMultiplier = 5000;        //2017/8/8 added

	timeouts.ReadTotalTimeoutConstant = 60000;

	timeouts.WriteTotalTimeoutMultiplier = 0;

	timeouts.WriteTotalTimeoutConstant = 0;

	SetCommTimeouts(m_hCom, &timeouts);

	

	//设置读写缓冲区大小

	static const int nZhenMax = 32768;

	if (!SetupComm(m_hCom, nZhenMax, nZhenMax))

	{

		AfxMessageBox("SetupComm() failed!");

		CloseHandle(m_hCom);

		return FALSE;

	}

	

	//设置串口配置信息

	DCB dcb;

	if (!GetCommState(m_hCom, &dcb))

	{

		AfxMessageBox("GetCommState() failed!");

		CloseHandle(m_hCom);

		return FALSE;

	}

	

	dcb.DCBlength = sizeof(DCB);

	dcb.BaudRate = baud;                   //波特率为115200    

	dcb.Parity = parity;                   //校验方式为无校验0

	dcb.ByteSize = databit;                //数据位为8位

	dcb.StopBits = stopbit;                //停止位为1位

	if (!SetCommState(m_hCom, &dcb))

	{

		AfxMessageBox("SetCommState() failed!");

		CloseHandle(m_hCom);

		return FALSE;

	}

	

	//清空缓冲

	PurgeComm(m_hCom, PURGE_RXCLEAR|PURGE_TXCLEAR);

	

	//清除错误

	DWORD dwError;

	COMSTAT cs;

	if (!ClearCommError(m_hCom, &dwError, &cs))

	{

		AfxMessageBox("ClearCommError() failed!");

		CloseHandle(m_hCom);

		return FALSE;

	}

	

	//设置串口监听事件

	SetCommMask(m_hCom, EV_RXCHAR);



	return TRUE;

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zgl7903 2017-08-10

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CreateFile 中的dwFlagsAndAttributes参数, 如果指定 FILE_FLAG_OVERLAPPED ，就是异步，不加就是同步

赵4老师 2017-08-09

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向MSDN98中自带的串口通信例子程序学习。 MSDN98_1.ISO http://pan.baidu.com/s/1dDF41ix, MSDN98_2.ISO http://pan.baidu.com/s/1bnGo0Vl MSDN98\SAMPLES\VC98\SDK\WINBASE\IO\SERIAL\*.*