RS232串口通讯DLL源代码

#include<afx.h> #include "RS232dll.h" bool OpenSerial(CString m_sPort) { COMMTIMEOUTS TimeOuts; if (m_bOpen) { return TRUE; } m_hCom = CreateFile(m_sPort, // communication port string (COMX) GENERIC_READ | GENERIC_WRITE, // read/write types 0, // comm devices must be opened with exclusive access NULL, // no security attributes OPEN_EXISTING, // comm devices must use OPEN_EXISTING FILE_FLAG_OVERLAPPED, // Async I/O 0); DCB dcb; dcb.DCBlength = sizeof(DCB); dcb.BaudRate = 9600; // 波特率 dcb.fParity = FALSE; dcb.ByteSize = 8; // 每字节位数 dcb.Parity = NOPARITY;//无奇偶检验 dcb.StopBits = ONESTOPBIT;//1个停止位 if (m_hCom == INVALID_HANDLE_VALUE) { return FALSE; } memset(&m_osRead, 0, sizeof(OVERLAPPED)); memset(&m_osWrite, 0, sizeof(OVERLAPPED)); SetupComm(m_hCom, MAXBLOCK,MAXBLOCK); SetCommMask(m_hCom, EV_RXCHAR); TimeOuts.ReadIntervalTimeout = MAXDWORD;// 把间隔超时设为最大，把总超时设为0将导致ReadFile立即返回并完成操作 TimeOuts.ReadTotalTimeoutMultiplier = 0; TimeOuts.ReadTotalTimeoutConstant = 0; TimeOuts.WriteTotalTimeoutMultiplier = 0; // 设置写超时以指定WriteComm成员函数中的GetOverlappedResult函数的等待时间 TimeOuts.WriteTotalTimeoutConstant = 5000; SetCommTimeouts(m_hCom, &TimeOuts); m_bOpen = TRUE; MessageBox(NULL,m_sPort,m_sPort,MB_OK); return TRUE; } void CloseSerial() { if(m_bOpen) { SetCommMask(m_hCom, 0); CloseHandle(m_hCom); m_bOpen = FALSE; MessageBox(NULL,"Close","Close",MB_OK); } } DWORD ReadSerial(unsigned char* chBuf, DWORD dwLength) { DWORD nLen; COMSTAT comStat; DWORD dwErrorFlags; ClearCommError(m_hCom, &dwErrorFlags, &comStat); nLen = min(dwLength, comStat.cbInQue); ReadFile(m_hCom, chBuf, nLen, &nLen, &m_osRead); return nLen; } DWORD WriteSerial(unsigned char *chBuf, DWORD dwLength) { BOOL bState; COMSTAT comStat; DWORD dwErrorFlags; ClearCommError(m_hCom, &dwErrorFlags, &comStat); bState = WriteFile(m_hCom, chBuf, dwLength, &dwLength, &m_osWrite); if(!bState) { if(GetLastError() == ERROR_IO_PENDING) { GetOverlappedResult(m_hCom, &m_osWrite, &dwLength, TRUE);// 等待 } else { dwLength = 0; } } return dwLength; }