串口通信的api方法.txt

win2k下直接用API函数编写串口通讯例程（VC6）.RAR。 直接用WINAPI编写的串口通讯例程。

	HANDLE hCom;
	char buf[100];
	unsigned char msg1[100];
	OVERLAPPED m_OverlappedRead, m_OverlappedWrite;

void CApicomDlg::OnTimer(UINT nIDEvent) 
{
	// TODO: Add your message handler code here and/or call default
	switch (nIDEvent)
	{
		case 1:  {
					Onsend(); 
					break;
				 }
		case 2:  {
					Onread(); 
					break;
				 }

	}
	CDialog::OnTimer(nIDEvent);
}
unsigned short CApicomDlg::Getcmd_CRC(unsigned char *cmdbuf,int cmdlen)
{
	unsigned short crcreg,crcbuf;
	int i,j;

	crcreg=0xffff;
	for(i=1;i<cmdlen;i++){
		crcreg=crcreg^cmdbuf[i];
		for(j=0;j<8;j++){
			crcbuf=crcreg;
			crcreg>>=1;
			if(crcbuf&0x01)
				crcreg^=0xa001;
		}
	}

	return crcreg;
}
void CApicomDlg::Oninit()   //初始化串口
{
	// TODO: Add your control notification handler code here
	UpdateData (true);
	unsigned char check_code=0;
	DCB dcb;
	int kk;
	COMMTIMEOUTS comtimeout;
	char szPort[100];
	tong=0;
	butong=-1;
	wsprintf( szPort, "COM%d", m_comsel+1 );
	strcpy ((char *)msg1,m_senddata);//"@01RD17");
	kk=strlen (m_senddata);	
	//*(unsigned short *)&msg1[kk]=Getcmd_CRC(msg1,kk);

	check_code=msg1[1];
	for (int i=2;i<kk;i++)
		check_code=check_code^msg1[i];
	if ((check_code&0x0f)>=0x0a)
		msg1[kk+1]=(check_code&0x0f)+0x37;
	else msg1[kk+1]=(check_code&0x0f)+0x30;
	if (((check_code>>4)&0x0f)>=0x0a)
		msg1[kk]=((check_code>>4)&0x0f)+0x37;
	else msg1[kk]=((check_code>>4)&0x0f)+0x30;

	msg1[kk+2]=0x0D;
	if (hCom)
	{
	if( m_OverlappedRead.hEvent != NULL ) CloseHandle( m_OverlappedRead.hEvent );
	if( m_OverlappedWrite.hEvent != NULL ) CloseHandle( m_OverlappedWrite.hEvent );
	CloseHandle( hCom);
	hCom= NULL;
	Sleep (10);
	}
	hCom=CreateFile( szPort, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL );
	if( hCom == INVALID_HANDLE_VALUE)
	{
		AfxMessageBox ("初始化不成功!");
		return ;
	}

	ZeroMemory(&dcb,sizeof(dcb));
	dcb.DCBlength=sizeof(dcb);
	kk=GetCommState(hCom,&dcb);
	dcb.BaudRate= m_baudrate;
	dcb.ByteSize=m_databit;
	dcb.fParity=1;
	dcb.Parity=m_parity;
	dcb.StopBits=m_stopbit;
	dcb.XoffChar=0x00;
	kk=SetCommState(hCom,&dcb);
	kk=GetCommTimeouts(hCom,&comtimeout);
	comtimeout.ReadIntervalTimeout =1;

	kk=SetCommTimeouts(hCom,&comtimeout);
	kk=SetupComm(hCom,512,512);//设置缓冲区大小
	memset( &m_OverlappedRead, 0, sizeof( OVERLAPPED ) );
 	memset( &m_OverlappedWrite, 0, sizeof( OVERLAPPED ) );
	m_OverlappedRead.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );
	m_OverlappedWrite.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );
	if (m_stime)
		SetTimer(1,m_stime,NULL);
	
}
void CApicomDlg::Onsend() //发送字符串函数
{
	
	DWORD ByteCount=400;
	unsigned char check_code=0;
	int kk;
	COMSTAT ComStat;
	DWORD dwErrorFlages;
	UpdateData (true);
	strcpy ((char *)msg1,m_senddata);//"@01RD17");
	kk=strlen (m_senddata);	
	msg1[2]=(((msg1[2]-48)%4)+49);
	m_senddata=msg1;
	check_code=msg1[1];  //求校验码
	for (int i=2;i<kk;i++)
		check_code=check_code^msg1[i];
	if ((check_code&0x0f)>=0x0a)
		msg1[kk+1]=(check_code&0x0f)+0x37;
	else msg1[kk+1]=(check_code&0x0f)+0x30;
	if (((check_code>>4)&0x0f)>=0x0a)
		msg1[kk]=((check_code>>4)&0x0f)+0x37;
	else msg1[kk]=((check_code>>4)&0x0f)+0x30;
	msg1[kk+2]=0x0D;
	kk=strlen ((char *)msg1);
	ClearCommError(hCom,&dwErrorFlages,&ComStat);
	WriteFile(hCom,msg1,kk,&ByteCount,&m_OverlappedWrite );//写文件发送
	if (m_rtime)
		SetTimer(2,m_rtime,NULL);
	if (m_stime)
		SetTimer(1,m_stime,NULL);
	
}



void CApicomDlg::Onread() //接收字符串函数
{	
	KillTimer( 2 );
	ZeroMemory(buf,sizeof(buf));
	unsigned long length=1;
	int RLength,i;
	COMSTAT ComStat;
	DWORD dwErrorFlages;

	CClientDC dc (this);
	char tempch[10];
	
	int flag=0;
	int temp=0;
	
	do {
		flag++;
	ClearCommError(hCom,&dwErrorFlages,&ComStat);
	RLength=ComStat.cbInQue;
	if(RLength>0)
	{
		for (i=0;i<RLength;i++)//以重叠方式接收指定字符，函数立即返回
		{
			ReadFile(hCom,&buf[temp],length,&length,&m_OverlappedRead);
			if ((buf[temp]==0x0d)||((temp>=5)&&(buf[temp]==0x00)))
			{
				//for (i=0;i<90;i++)
				//	buf[i]=buf[i+1];
				char buff[4];
				for (i= 0 ;i<2;i++)
				{
				if (buf[9+i]>0x39) 
					buff[i] = buf[9+i]-0x37;
				else buff[i] = buf[9+i]-0x30;
				}
				for (i= 0 ;i<2;i++)
				{
				if (buf[7+i]>0x39) 
					buff[2+i] = buf[7+i]-0x37;
				else buff[2+i] = buf[7+i]-0x30;
				}
				if (buf[2]==49)
					m_data=CS16toint(buff);
				else if (buf[2]==50)
					m_data2=CS16toint(buff);
				else if (buf[2]==51)
					m_data3=CS16toint(buff);
				else if (buf[2]==52)
					m_data4=CS16toint(buff);
				else 
					butong++;
				
				m_readdata=buf;
				UpdateData (FALSE);
				
				return;
			}
			else temp++;
		}
		
	}
	
	}
	while (flag<20);
	
	
}

void CApicomDlg::Onpause()   //暂停通讯
{
	// TODO: Add your control notification handler code here
	KillTimer( 1 );
	KillTimer( 2 );

	if (hCom)
	{
	if( m_OverlappedRead.hEvent != NULL ) CloseHandle( m_OverlappedRead.hEvent );
	if( m_OverlappedWrite.hEvent != NULL ) CloseHandle( m_OverlappedWrite.hEvent );
	CloseHandle( hCom);
	hCom= NULL;
	}
}

float CApicomDlg::CS16toint(char *buff) //十六进制转十进制
{
	int disp_v=1;
	int i=0;
	signed short int disp_v1;
	

	 disp_v1 = buff[0]*0x1000+ \
			  buff[1]*0x100 + \
			  buff[2]*0x10  + \
			  buff[3];
	float disp=disp_v1;
	for (i=0;i<buf[12]-48;i++)
		disp_v =disp_v*10;
	
	return disp/disp_v;
}