三、程序代码
//////////////////////////////////////////////////////////////
#if !defined(_COMM_ACCESS_FUNCTIONS_AND_DATA)
#define _COMM_ACCESS_FUNCTIONS_AND_DATA
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#define EVENTCHAR 0x0d
#define MAXBLOCKLENGTH 59
extern BYTE XwCom;
extern BYTE sCom1[5],sCom2[MAXBLOCKLENGTH+12]；
extern sCom3[MAXBLOCKLENGTH+12];
extern BYTE opation;
extern short ComNum;
#define FC_DTRDSR 0x01
#define FC_RTSCTS 0x02
#define FC_XONXOFF 0x04
#define ASCII_BEL 0x07
#define ASCII_BS 0x08
#define ASCII_LF 0x0A
#define ASCII_CR 0x0D
#define ASCII_XON 0x11
#define ASCII_XOFF 0x13
class CComStatus
{
public:
HANDLE m_hCom;
BYTE m_bComId;
BYTE m_bByteSize;
BYTE m_bStopBits;
BYTE m_bParity;
DWORD m_dwBaudRate;
//WORD m_fChEvt;
char m_bEvtChar;
DWORD m_fBinary;
BOOL m_bConnected;
BOOL m_fXonXoff;
BOOL m_bFlowCtrl;
OVERLAPPED m_rdos;
OVERLAPPED m_wtos;
//functions
CComStatus();
CComStatus(BYTE bComId,BYTE bByteSize,BYTE bStopBits,BYTE bParity,
DWORD dwBaudRate,/*WORD fChEvt,*/char bEvtChar,DWORD fBinary);
BOOL OpenConnection();
BOOL CloseConnection();
BOOL SetupConnection();
BOOL IsConnected();
};
UINT CommWatchProc( LPVOID lpData );
BOOL WriteCommBlock( CComStatus& comDev, LPSTR lpByte , DWORD dwBytesToWrite);
int ReadCommBlock(CComStatus& comDev,LPSTR lpszBlock, int nMaxLength );
int ReadCommBlockEx(CComStatus& comDev,LPSTR lpszBlock, int nMaxLength,DWORD dwTimeOut);
#endif
///////////////////////////////////////////////////////////////////////
#include "stdafx.h"
#include "com232.h"
BYTE XwCom=0x40;
BYTE sCom1[5],sCom2[MAXBLOCKLENGTH+12],sCom3[MAXBLOCKLENGTH+12];
BYTE opation;
short ComNum;
CComStatus::CComStatus()
{
m_hCom = NULL;
m_bComId = (char)ComNum;//COM1
m_bByteSize=8;
m_bStopBits=ONESTOPBIT;
m_bParity=NOPARITY;
m_dwBaudRate=9600;
m_bEvtChar=EVENTCHAR;
m_fBinary=1;
m_bConnected = FALSE;
m_bFlowCtrl = FC_XONXOFF ;
m_fXonXoff = FALSE;
}
CComStatus::CComStatus(BYTE bComId,BYTE bByteSize,BYTE bStopBits,BYTE bParity,DWORD dwBaudRate,/*WORD fChEvt,*/char bEvtChar,DWORD fBinary)
{
m_hCom = NULL;
m_bComId = bComId;
m_bByteSize=bByteSize;
m_bStopBits=bStopBits;
m_bParity=bParity;
m_dwBaudRate=dwBaudRate;
m_bEvtChar=bEvtChar;
m_fBinary=fBinary;
m_bConnected = FALSE;
m_bFlowCtrl = FC_XONXOFF ;
m_fXonXoff = FALSE;
}
BOOL CComStatus::OpenConnection()
{
char csCom[10];
COMMTIMEOUTS CommTimeOuts ;
if((m_bComId < 0) || (m_bComId > 4))
return FALSE;//从COM1到COM4
if(m_hCom)//if already open
return FALSE;
//OVERLAPPED包含异步I/O信息
m_rdos.Offset = 0;
m_rdos.OffsetHigh = 0;
m_rdos.hEvent = CreateEvent(NULL,TRUE,FALSE,NULL);
if(m_rdos.hEvent == NULL)
return FALSE;
m_wtos.Offset = 0;
m_wtos.OffsetHigh = 0;
m_wtos.hEvent = CreateEvent(NULL,TRUE,FALSE,NULL);
if(m_wtos.hEvent == NULL)
{
CloseHandle(m_rdos.hEvent);
return FALSE;
}
wsprintf(csCom,"COM%d",m_bComId);
m_hCom = CreateFile(csCom,GENERIC_READ | GENERIC_WRITE, 0,NULL, OPEN_EXISTING,ILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED,NULL);
if(m_hCom == INVALID_HANDLE_VALUE) {
//dwError = GetLastError();
// handle error
return FALSE;
}
else
{
SetCommMask( m_hCom, EV_RXCHAR ) ; // get any early notifications
SetupComm( m_hCom, 4096, 4096 ) ; // setup device buffers
// purge any information in the buffer
PurgeComm( m_hCom, PURGE_TXABORT | PURGE_RXABORT |PURGE_TXCLEAR | PURGE_RXCLEAR ) ;
// set up for overlapped I/O
DWORD dwTemp = 1000 / (this->m_dwBaudRate / 8);
CommTimeOuts.ReadIntervalTimeout = 0xFFFFFFFF ;
CommTimeOuts.ReadTotalTimeoutMultiplier = 0;//((dwTemp > 0) ? dwTemp : 1);
CommTimeOuts.ReadTotalTimeoutConstant = 1000 ;
// CBR_9600 is approximately 1byte/ms. For our purposes, allow
// double the expected time per character for a fudge factor.
CommTimeOuts.WriteTotalTimeoutMultiplier =2*CBR_9600/this->m_dwBaudRate;//( npTTYInfo ) ;
CommTimeOuts.WriteTotalTimeoutConstant = 0;//1000 ;
SetCommTimeouts( m_hCom, &CommTimeOuts ) ;
}
if(!SetupConnection())
{
CloseConnection();
return FALSE;
}
EscapeCommFunction( m_hCom, SETDTR );
m_bConnected = TRUE;
return TRUE;
}
BOOL CComStatus::CloseConnection()
{
if (NULL == m_hCom)
return ( TRUE ) ;
// set connected flag to FALSE
m_bConnected = FALSE;
// disable event notification and wait for thread
// to halt
SetCommMask( m_hCom, 0 ) ;
EscapeCommFunction( m_hCom, CLRDTR ) ;
// purge any outstanding reads/writes and close device handle
PurgeComm( m_hCom, PURGE_TXABORT | PURGE_RXABORT | PURGE_TXCLEAR | PURGE_RXCLEAR ) ;
CloseHandle( m_hCom ) ;
m_hCom = NULL;
// change the selectable items in the menu
CloseHandle(m_rdos.hEvent);
CloseHandle(m_wtos.hEvent);
return ( TRUE ) ;
}
BOOL CComStatus::SetupConnection()
{
BOOL fRetVal ;
BYTE bSet ;
DCB dcb ;
if(m_hCom == NULL)
return FALSE;
dcb.DCBlength = sizeof( DCB ) ;
GetCommState( m_hCom, &dcb ) ;
dcb.BaudRate = this->m_dwBaudRate;
dcb.ByteSize = this->m_bByteSize;
dcb.Parity = this->m_bParity;
dcb.StopBits = this->m_bStopBits ;
dcb.EvtChar = this->m_bEvtChar ;
// setup hardware flow control
bSet = (BYTE) ((m_bFlowCtrl & FC_DTRDSR) != 0) ;
dcb.fOutxDsrFlow = bSet ;
if (bSet)
dcb.fDtrControl = DTR_CONTROL_HANDSHAKE ;
else
dcb.fDtrControl = DTR_CONTROL_ENABLE ;
bSet = (BYTE) ((m_bFlowCtrl & FC_RTSCTS) != 0) ;
dcb.fOutxCtsFlow = bSet ;
if (bSet)
dcb.fRtsControl = RTS_CONTROL_HANDSHAKE ;
else
dcb.fRtsControl = RTS_CONTROL_ENABLE ;
// setup software flow control
bSet = (BYTE) ((m_bFlowCtrl & FC_XONXOFF) != 0) ;
dcb.fInX = dcb.fOutX = bSet ;
dcb.XonChar = ASCII_XON ;
char xon = ASCII_XON ;
dcb.XoffChar = ASCII_XOFF ;
char xoff = ASCII_XOFF ;
dcb.XonLim = 100 ;
dcb.XoffLim = 100 ;
// other various settings
dcb.fBinary = TRUE ;
dcb.fParity = TRUE ;
fRetVal = SetCommState( m_hCom, &dcb ) ;
return ( fRetVal ) ;
} // end of SetupConnection()
BOOL CComStatus::IsConnected()
{
return m_bConnected;
}
UINT CommWatchProc( LPVOID lpData )
{
DWORD dwEvtMask ;
//NPTTYINFO npTTYInfo = (NPTTYINFO) lpData ;
OVERLAPPED os ;
int nLength ;
//BYTE abIn[ MAXBLOCK + 1] ;
CComStatus * pCom = (CComStatus *)lpData;
memset( &os, 0, sizeof( OVERLAPPED ) ) ;
// create I/O event used for overlapped read
os.hEvent = CreateEvent( NULL, // no security
TRUE, // explicit reset req
FALSE, // initial event reset
NULL ) ; // no name
if (os.hEvent == NULL)
{
MessageBox( NULL, "Failed to create event for thread!", "TTY Error!",MB_ICONEXCLAMATION | MB_OK ) ;
return ( FALSE ) ;
}
if (!SetCommMask( pCom->m_hCom, EV_RXCHAR ))
return ( FALSE ) ;
char buf[256];
while ( pCom->m_bConnected )
{
dwEvtMask = 0 ;
WaitCommEvent( pCom->m_hCom, &dwEvtMask, NULL );
if ((dwEvtMask & EV_RXCHAR) == EV_RXCHAR)
{
if ((nLength = ReadCommBlock( *pCom, (LPSTR) buf, 255 )))
{
//WriteTTYBlock( hTTYWnd, (LPSTR) abIn, nLength ) ;
buf[nLength]='/0';
AfxMessageBox(buf);
}
}
}
CloseHandle( os.hEvent ) ;
return( TRUE ) ;
} // end of CommWatchProc()
int ReadCommBlock(CComStatus& comDev,LPSTR lpszBlock, int nMaxLength )
{
BOOL fReadStat ;
COMSTAT ComStat ;
DWORD dwErrorFlags;
DWORD dwLength;
DWORD dwError;
char szError[ 10 ] ;
// only try to read number of bytes in queue
ClearCommError( comDev.m_hCom, &dwErrorFlags, &ComStat ) ;
dwLength = min( (DWORD) nMaxLength, ComStat.cbInQue ) ;
if (dwLength > 0)
{
fReadStat = ReadFile( comDev.m_hCom, lpszBlock,dwLength, &dwLength, &(comDev.m_rdos) ) ;
if (!fReadStat)
{
if (GetLastError() == ERROR_IO_PENDING)
{
OutputDebugString("/n/rIO Pending");
while(!GetOverlappedResult( comDev.m_hCom ,&(comDev.m_rdos), &dwLength, TRUE ))
{
dwError = GetLastError();
if(dwError == ERROR_IO_INCOMPLETE)
// normal result if not finished
continue;
else
{
// an error occurred, try to recover
wsprintf( szError, "<CE-%u>", dwError ) ;
ClearCommError( comDev.m_hCom , &dwErrorFlags, &ComStat ) ;
break;
}
}
}
else
{
// some other error occurred
dwLength = 0 ;
ClearCommError( comDev.m_hCom , &dwErrorFlags, &ComStat ) ;
}
}
}
return ( dwLength ) ;
} // end of ReadCommBlock()
int ReadCommBlockEx(CComStatus& comDev,LPSTR lpszBlock, int nMaxLength,DWORD dwTimeOut)
{
LPSTR lpOffset=lpszBlock;
int nReadCount = 0;
char chBuf;
//time_t beginTime,endTime;
if(!comDev.m_hCom)
return 0;
if(dwTimeOut <= 0)
return 0;
MSG msg;
//time(&beginTime);
DWORD dwLastTick,dwNowTick,dwGoneTime;
dwGoneTime = 0;
dwLastTick = GetTickCount();
dwNowTick = dwLastTick;
// double diftime;
do
{
if(PeekMessage(&msg,NULL,0,0,PM_REMOVE))
{
::TranslateMessage(&msg);
::DispatchMessage(&msg);
}
if(ReadCommBlock(comDev,&chBuf,1) > 0)
{
//TRACE("----get a char----/n");
*lpOffset = chBuf;
lpOffset ++;
nReadCount ++;
}
dwNowTick = GetTickCount();
if(dwNowTick < dwLastTick)
{
dwLastTick = dwNowTick;
}
dwGoneTime = dwNowTick - dwLastTick;
//TRACE("gon time = %lu/n",dwGoneTime);
}while((nReadCount < nMaxLength) && (dwGoneTime < dwTimeOut));
return (nReadCount);
}//end ReadCommBlockEx
BOOL WriteCommBlock( CComStatus& comDev, LPSTR lpByte , DWORD dwBytesToWrite)
{
BOOL fWriteStat ;
DWORD dwBytesWritten ;
DWORD dwErrorFlags;
DWORD dwError;
DWORD dwBytesSent=0;
COMSTAT ComStat;
char szError[ 128 ] ;
fWriteStat = WriteFile( comDev.m_hCom , lpByte, dwBytesToWrite,&dwBytesWritten, &( comDev.m_wtos) ) ;
if (!fWriteStat)
{
if(GetLastError() == ERROR_IO_PENDING)
{
while(!GetOverlappedResult( comDev.m_hCom,&(comDev.m_wtos), &dwBytesWritten, TRUE ))
{
dwError = GetLastError();
if(dwError == ERROR_IO_INCOMPLETE)
{
// normal result if not finished
dwBytesSent += dwBytesWritten;
continue;
}
else
{
// an error occurred, try to recover
wsprintf( szError, "<CE-%u>", dwError ) ;
ClearCommError( comDev.m_hCom, &dwErrorFlags, &ComStat ) ;
break;
}
}
dwBytesSent += dwBytesWritten;
if( dwBytesSent != dwBytesToWrite )
wsprintf(szError,"/nProbable Write Timeout: Total of %ld bytes sent", dwBytesSent);
else
wsprintf(szError,"/n%ld bytes written", dwBytesSent);
OutputDebugString(szError);
}
else
{
// some other error occurred
ClearCommError( comDev.m_hCom, &dwErrorFlags, &ComStat ) ;
return ( FALSE );
}
}
return ( TRUE ) ;
} // end of WriteCommBlock() |
四、小结
以上给出了用Win32 API设计串行通信的基本思路，在实际应用中，我们可以利用Win32 API设计出满足各种需要的串行通信程序。
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