rs232.cpp

自用的RS232串口通信模块,可以在VC和C++ Builder中编译.

//---------------------------------------------------------------------------


#pragma hdrstop

#include "windows.h"
#include <tchar.h>
#include <stdio.h>
#include "RS232.h"
#include "TimeUtil.h"
//---------------------------------------------------------------------------

#pragma package(smart_init)


#define IN_BUFFER_SIZE  8192
#define OUT_BUFFER_SIZE  IN_BUFFER_SIZE
#define RCV_RING_SIZE  IN_BUFFER_SIZE

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CRS232::CRS232(const BOOL bXonXoff)
{
	m_hComPort = INVALID_HANDLE_VALUE;
	m_byPort = 1; //COM1
	m_dwBaudRate = 19200; //default value
	m_bXonXoff = bXonXoff;
	m_iManualIntervalTimeout = 10;
	m_iManualTotalTimeout = 200;
}

CRS232::~CRS232()
{
	CloseSerialPort();
}

void CRS232::SetRTS(int val)
{
	if(val)
		EscapeCommFunction(m_hComPort, SETRTS);
	else
		EscapeCommFunction(m_hComPort, CLRRTS);
}

void CRS232::SetDTR(int val)
{
	if(val)
		EscapeCommFunction(m_hComPort, SETDTR);
	else
		EscapeCommFunction(m_hComPort, CLRDTR);
}

int CRS232::WriteBytes(const void *buf, int num)
{
	if(m_hComPort == INVALID_HANDLE_VALUE)
		return 0;

	DWORD nWrite = 0;
	BOOL bSuccess = WriteFile(m_hComPort, buf, num, &nWrite, 0);
	if(bSuccess && (nWrite == (DWORD)num))
		return num;
	else
		return 0;

}

int CRS232::ReadBytes(BYTE *byRcv, const DWORD dwMaxBytes, BOOL bAuto, BOOL bInterval)
{
	DWORD dwRdBytes = dwMaxBytes;
	
	if((m_hComPort == INVALID_HANDLE_VALUE) || (dwRdBytes > RCV_RING_SIZE))
		return 0;

//	bAuto = TRUE;
	if (!bAuto) 
	{
		dwRdBytes = 0;
//		DWORD dwInBufferBytes = 0;
		DWORD dwStartTime = ::GetTickCount();

		while(TRUE)
		{
			DWORD dwNowTime = ::GetTickCount();
			
			if(dwNowTime - dwStartTime > m_iManualTotalTimeout)
				break;

			DWORD dwErrorMask;
			COMSTAT comstat;
			ClearCommError(m_hComPort, &dwErrorMask, &comstat);
			if(comstat.cbInQue == 0)
			{
//				Sleep(5);
				delay(5);
				continue;
			}
			else
			{
				if(dwRdBytes != comstat.cbInQue)
				{
					dwRdBytes = comstat.cbInQue;
//					Sleep(m_iManualIntervalTimeout);
					delay(m_iManualIntervalTimeout);
				}
				else
				{
					if (bInterval) //20080306
						break;
				}
			}
		}
	}

	if (dwRdBytes==0)
		return 0;

	DWORD dwNumRead = 0;
	BOOL bSuccess = ReadFile(m_hComPort, byRcv, dwRdBytes, &dwNumRead, NULL);
	if(bSuccess)
		return (int)dwNumRead;
	else
		return 0;
}

BOOL CRS232::OpenSerialPort(const BYTE byPort, const DWORD dwBaudRate) 
{
	if (m_hComPort!=INVALID_HANDLE_VALUE && byPort==m_byPort && m_dwBaudRate==dwBaudRate) 
		return TRUE;
	
	CloseSerialPort();
	m_byPort = byPort;
	m_dwBaudRate = dwBaudRate;
	TCHAR szCOMPort[MAX_PATH];
	_stprintf(szCOMPort, TEXT("\\\\.\\COM%d"), m_byPort);

	m_hComPort = CreateFile(szCOMPort, 
		GENERIC_READ | GENERIC_WRITE, 
		0,
		NULL,
		OPEN_EXISTING, 
		FILE_ATTRIBUTE_NORMAL,
		NULL);
	
	if(m_hComPort == INVALID_HANDLE_VALUE)
		return FALSE;
	
	DCB  dcb;
	dcb.DCBlength = sizeof(dcb);
	
	if(!GetCommState(m_hComPort, &dcb))
	{
		CloseSerialPort();
		return FALSE;
	}
	
	memcpy(&m_dcbPrev, &dcb, sizeof(DCB));

	//basic settings
	dcb.BaudRate = m_dwBaudRate;
	dcb.ByteSize = 8;
	dcb.Parity = NOPARITY;
	dcb.StopBits = ONESTOPBIT;
	
	//common
	dcb.fBinary = TRUE; //MUST
	dcb.fParity = FALSE;
	
	//hardware control
	dcb.fDtrControl = DTR_CONTROL_ENABLE;//DTR_CONTROL_DISABLE;
	dcb.fOutxCtsFlow = FALSE;
	dcb.fRtsControl = RTS_CONTROL_DISABLE;

	dcb.fDsrSensitivity = FALSE;
	dcb.fOutxCtsFlow = FALSE;
	dcb.fOutxDsrFlow = FALSE;
	
	//software control
	if(TRUE == m_bXonXoff)
	{
		dcb.fInX = TRUE;
		dcb.fOutX = TRUE;
		dcb.XonChar = (char)0x11; //DC1
		dcb.XoffChar = (char)0x13; //DC3
		dcb.EvtChar = (char)0x0A;
	}
	else
	{
		dcb.fInX = FALSE;
		dcb.fOutX = FALSE;
		dcb.XonChar = (char)0xFF;
		dcb.XoffChar = (char)0xFF;
		dcb.EvtChar = (char)0xFF;//0x00;
	}

	dcb.XoffLim = 100;
	dcb.XonLim = 100;
	
	///////////
	dcb.fAbortOnError	= FALSE;
	dcb.fBinary			= TRUE;		//Windows must be TRUE
	dcb.fNull			= FALSE;	//MUST
 	dcb.ErrorChar		= 0x00;
	dcb.EofChar			= 0x00;
	dcb.fErrorChar		= FALSE;
	///////////

	// Set the new comm port settings
	if(!SetCommState(m_hComPort, &dcb))
	{
		CloseSerialPort();
		return FALSE;
	}
	
	//3. Set timeout
	COMMTIMEOUTS tos;

	// Set the timeouts so that ReadFile will return after certain time
	tos.ReadIntervalTimeout = 0;
	tos.ReadTotalTimeoutMultiplier = 0;
	tos.ReadTotalTimeoutConstant = 250;
	tos.WriteTotalTimeoutMultiplier = 10;
	tos.WriteTotalTimeoutConstant = 0;

	if(!SetCommTimeouts(m_hComPort, &tos))
	{
		CloseSerialPort();
		return FALSE;
	}
	
	//4. Init serial port
	if(!SetupComm(m_hComPort, IN_BUFFER_SIZE, OUT_BUFFER_SIZE))
	{
		CloseSerialPort();
		return FALSE;
	}
	
	//5. Clear IN/OUT buffer
	if(!PurgeComm(m_hComPort, PURGE_TXCLEAR | PURGE_RXCLEAR))
	{
		CloseSerialPort();
		return FALSE;
	}

#if 0
	//6. Clear the Data Terminal Ready (DTR) line and Request to Send (RTS) line
	EscapeCommFunction(m_hComPort, CLRDTR);
	EscapeCommFunction(m_hComPort, CLRRTS);
#endif
	return TRUE;
}

void CRS232::CloseSerialPort()
{
	if(m_hComPort != INVALID_HANDLE_VALUE)
	{
		SetCommState(m_hComPort, &m_dcbPrev);
		SetCommTimeouts(m_hComPort, &m_timeoutPrev);

		PurgeComm(m_hComPort, PURGE_RXCLEAR | PURGE_TXCLEAR);
		CloseHandle(m_hComPort);
		m_hComPort = INVALID_HANDLE_VALUE;
	}
}

//Wait for dwTimeout ms.
//Check how many byte(s) received.
UINT CRS232::CheckInbuffer(const DWORD dwTimeout)
{
	if(m_hComPort == INVALID_HANDLE_VALUE)
		return 0;
	
	DWORD dwInBufferBytes = 0;
	DWORD dwStartTime = ::GetTickCount();
	BYTE byNoMoreCnt = 0;
	
	while(TRUE)
	{
		//check if timeout
		DWORD dwNowTime = ::GetTickCount();
		
		if(dwNowTime - dwStartTime > dwTimeout)
			break;
		
		//how many bytes in RX buffer?
		DWORD dwErrorMask;
		COMSTAT comstat;
		ClearCommError(m_hComPort, &dwErrorMask, &comstat);
		DWORD dwLastCheckLength = dwInBufferBytes; //keep last time check va
		dwInBufferBytes = comstat.cbInQue;
		
		if(dwInBufferBytes == 0) //no byte received yet
		{
			delay(5);
			continue; //can be timeout after dwTimeout ms
		}
		else
		{
			if(dwInBufferBytes == dwLastCheckLength) //no more bytes received this round, assume there is no more bytes from FW
			{
				if(++byNoMoreCnt >= 1 && (dwNowTime - dwStartTime > dwTimeout)) //no more byte(s) received.
					break;
			}
			else //may be more
				byNoMoreCnt = 0;
		}
		delay(12);
	}
	return (UINT)dwInBufferBytes;
}

void CRS232::ClearAllBuffer()
{
	if(m_hComPort != INVALID_HANDLE_VALUE)
	{
		PurgeComm(m_hComPort, PURGE_TXCLEAR | PURGE_RXCLEAR | PURGE_TXABORT | PURGE_RXABORT);
	}
}

void CRS232::SetReadTimeOut(int ims)
{
	COMMTIMEOUTS tos;
	GetCommTimeouts(m_hComPort, &tos);
	tos.ReadTotalTimeoutMultiplier = 0;
	tos.ReadTotalTimeoutConstant = ims;
	SetCommTimeouts(m_hComPort, &tos);
}

void CRS232::SetWriteTimeOut(int ims)
{
	COMMTIMEOUTS tos;
	GetCommTimeouts(m_hComPort, &tos);
	tos.WriteTotalTimeoutMultiplier = 0;
	tos.WriteTotalTimeoutConstant = ims;
	SetCommTimeouts(m_hComPort, &tos);
}