用API操作串口-白红宇

用API操作串口

阅读量：5963 次

发布时间：2019-06-19

本文共 3522 字，大约阅读时间需要 11 分钟。

步骤：

　　1、CreateFile，打开串口

　　示例：g_hCOM = CreateFile(L"COM3", GENERIC_READ| GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);　　

　　//必须用0,表示以独占的模式来占用串口

　　//打开除文件之外的设备时，用 OPEN_EXISTING

　　2、SetupComm，用来设置缓存大小

　　3、SetCommTimeouts，设置读写的超时时间

　　4、SetCommState，用来设置一些串口参数，如波特率，读取的字节数，是否奇偶检验。

　　5、WriteFile，向串口发送数据

　　6、ReadFile，从串口读数据

　　7、采用异步的方式来获取数据，如IO完成端口

代码：

#include 
     
      #include 
      
       #include 
       
        #include 
        
         using namespace std;HANDLE g_hCompletionPort, g_hCOM, g_hEvent;byte buff[1000];byte writeBuf = 0x1a;//这个数据是针对我这块板子的DWORD dwErr;UINT WINAPI WriteData(PVOID pParameter){	OVERLAPPED overLap;	overLap.hEvent = 0;	overLap.Offset = 0;	overLap.OffsetHigh = 0;	DWORD dwWrite;	WriteFile(g_hCOM, &writeBuf, sizeof(writeBuf), &dwWrite, &overLap);	DWORD dwTransLen = 0;	DWORD dwKey = 0;	LPOVERLAPPED  poverLap;	BOOL IsOk = GetQueuedCompletionStatus(g_hCompletionPort, &dwTransLen, &dwKey, &poverLap, INFINITE);	if(IsOk)	{		cout << "Translate Num：　" <
         
          InternalHigh << endl;		cout << "Write Success" << endl;		SetEvent(g_hEvent);	}	else	{		dwErr = GetLastError();		cout << "Write Failed. Code = " << dwErr << endl;	}	return 0;}UINT WINAPI ReadData(PVOID pParame){	//SetCommMask(g_hCOM, EV_RXCHAR | EV_TXEMPTY);	OVERLAPPED overLap;	overLap.hEvent = 0;	overLap.Offset = 0;	overLap.OffsetHigh = 0;	ReadFile(g_hCOM, buff, 1000, 0, &overLap);	DWORD dwTransLen = 0;	DWORD dwKey = 0;	LPOVERLAPPED  poverLap = {0};	BOOL IsOk = GetQueuedCompletionStatus(g_hCompletionPort, &dwTransLen, &dwKey, &poverLap, INFINITE);	if(IsOk)	{		cout << "Read Success." << endl;		cout << "The Length is : " << poverLap->InternalHigh << endl;		for (int i = 0; i < 10; i++)		{			printf("%02X  ", buff[i]);		}		cout << endl << endl;	}	else	{		dwErr = GetLastError();		cout << "Read failed. Code = : " << dwErr << endl;	}	SetEvent(g_hEvent);	return 0;}void main(){	g_hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);	//创建IO完成端口	g_hCompletionPort = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, NULL, 0);	//打开文件	g_hCOM = CreateFile(L"COM3", GENERIC_READ| GENERIC_WRITE, 0, NULL, 		OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);	//将该设备（文件）与IO完成端口相关联，以获得通知	HANDLE h = CreateIoCompletionPort(g_hCOM, g_hCompletionPort, NULL, 0);	if(h == g_hCompletionPort)		cout << "关联成功" << endl;	else	{		dwErr = GetLastError();		cout << "关联失败 : " << dwErr << endl;	}//	SetCommMask(g_hCOM, EV_RXCHAR | EV_TXEMPTY);	SetupComm(g_hCOM, 1024, 512);	PurgeComm(g_hCOM, PURGE_RXABORT | PURGE_RXCLEAR | PURGE_TXABORT | PURGE_TXCLEAR);	COMMTIMEOUTS CommTimeout;	CommTimeout.ReadIntervalTimeout = 5;	CommTimeout.ReadTotalTimeoutConstant = 1000;	CommTimeout.ReadTotalTimeoutMultiplier = 5;	CommTimeout.WriteTotalTimeoutConstant = 1000;	CommTimeout.WriteTotalTimeoutMultiplier = 5;	SetCommTimeouts(g_hCOM, &CommTimeout);	DCB dcb;	GetCommState(g_hCOM, &dcb);	dcb.BaudRate = 4800;	dcb.ByteSize = 8;	dcb.Parity = NOPARITY;	dcb.StopBits = ONESTOPBIT;	dcb.fBinary = TRUE;	dcb.fParity = FALSE;	SetCommState(g_hCOM, &dcb);	HANDLE hThread[20];	hThread[0] = (HANDLE)_beginthreadex(NULL, 0, WriteData, NULL, 0, NULL);	for (int i = 1; i < 20; i++)	{		WaitForSingleObject(g_hEvent, INFINITE);		hThread[i] = (HANDLE)_beginthreadex(NULL, 0, ReadData, NULL, 0, NULL);		ResetEvent(g_hEvent);	}	WaitForMultipleObjects(20, hThread, TRUE, INFINITE);	CloseHandle(g_hCOM);	CloseHandle(g_hCompletionPort);	CloseHandle(g_hEvent);}