serialport.cpp

使用C#开发的串口读写例程

#include "SerialPort.h"
#include "assert.h"
#include "fcntl.h"
#include <sys/select.h>


csSerialPort::csSerialPort()
{	
	 fd = 8888;		// a invalid value
}





csSerialPort::~csSerialPort()
{	

}





void csSerialPort::Open(char * device, int nBaudRate, int Parity, int DataBits, int stopbits)
{
	/* open with read and write */
	fd = open(device, O_RDWR);
	
	// open
	if (-1 == fd)
	{ 
		perror("Com open error");
	}
	
	// set nBaudRate
	set_Speed(fd, nBaudRate);

	// setupserial
	set_Parity(fd, DataBits, stopbits, Parity);

}





void csSerialPort::set_Speed(int fd, int speed)
{
	speed_t BaudRates[8] = {B2400, B4800, B9600, B9600, B9600, B9600, B9600, B19200};

	int status; 

	struct termios Opt;
	tcgetattr(fd, &Opt); 
	
	tcflush(fd, TCIOFLUSH);
	 
	assert( (2400 <= speed) && (speed <= 19200));
	//assert(1);

	cfsetispeed(&Opt, BaudRates[(speed/2400) - 1]); 
	cfsetospeed(&Opt, BaudRates[(speed/2400) - 1]); 

	status = tcsetattr(fd, TCSANOW, &Opt); 
		
	if (status != 0)
	{ 
		perror("tcsetattr"); 
		return; 
	} 
	tcflush(fd,TCIOFLUSH); 
}





int  csSerialPort::set_Parity(int fd, int databits, int stopbits, int parity)
{
//	printf("databits = %d, stopbits = %d, parity = %d\n", databits, stopbits, parity);

	struct termios options; 
	if (tcgetattr(fd, &options) != 0)
	{ 
		//perror("SetupSerial"); 
		return(false); 
	}

	options.c_cflag &= ~CSIZE; 
	
	/* set databits */
	switch (databits)
	{ 
		case 7: 
			options.c_cflag |= CS7; break;
		
		case 8: 
			options.c_cflag |= CS8; break; 
		
		default: 
			//fprintf(stderr, "Unsupported data sizen");
            return (false); 
	}

	/* set parity */
	switch (parity) 
	{ 
		/////////////////
		/*
		enum Parity
		{    
		0 EvenParity,
		1 MarkParity,
		2 NoParity,
		3 OddParity,
		4 SpaceParity
		};
		*/
		////////////////

//		case 'n':	//	NoParity?
//		case 'N': 
		case 0 : 
			options.c_cflag &= ~PARENB; /* Clear parity enable */
			options.c_iflag &= ~INPCK;  /* Enable parity checking */
			break; 

//		case 'o':	// OddParity ?
//		case 'O': 
		case 3 :
			options.c_cflag |= (PARODD | PARENB);	/* 设置为奇效验*/ 
			options.c_iflag |= INPCK;				/* Disnable parity checking */ 
			break; 

//		case 'e': 
//		case 'E': 
		case 2 :
			options.c_cflag |= PARENB; /* Enable parity */ 
			options.c_cflag &= ~PARODD; /* 转换为偶效验*/ 
			options.c_iflag |= INPCK; /* Disnable parity checking */
			break;

//		case 'S': 
//		case 's': /*as no parity*/ 
		case 4 :
			options.c_cflag &= ~PARENB;
			options.c_cflag &= ~CSTOPB;
			break; 
		
		default: 
			//fprintf(stderr,"Unsupported parityn"); 
			return (false); 
	} 
		
	/* Set stopbits*/ 
	switch (stopbits)
	{ 

		///////////
		/*
		enum StopBits
		{
		OneStopBit,
		OnePointFiveStopBits,
		TwoStopBits
		};
		*/
		////////////

		case 0:								
			options.c_cflag &= ~CSTOPB; break;		// 不指明表示一位停止位 

		case 2: 
			options.c_cflag |= CSTOPB;  break;		// 指明CSTOPB表示两位，只有两种可能

		default: 
			//fprintf(stderr,"Unsupported stop bitsn"); 
			return (false); 
	} 

	/* Set input parity option */ 
	if (parity != 2) 
	{	
		options.c_iflag |= INPCK; 
	}
	
	tcflush(fd, TCIFLUSH);
	options.c_cc[VTIME] = 150;	/* 设置超时15 seconds*/ 
	options.c_cc[VMIN] = 0;		/* Update the options and do it NOW */
	
	if (tcsetattr(fd, TCSANOW, &options) != 0) 
	{ 
		perror("SetupSerial 2"); 
		return (false); 
	} 
	return (true);	
}





int csSerialPort::Read (BYTE *buffer, int Length)
{
	int result =  read(fd, buffer, Length);
	return result;
}





int csSerialPort::Select(long sec, long usec)
{
	//printf("the fd is %d\n", fd);

	fd_set rset;
	FD_ZERO(&rset);
	FD_SET(fd, &rset);
	timeval tv;
	tv.tv_sec = sec;
	tv.tv_usec = usec;
	int nfds = fd + 1;
		
	int result = select(nfds, &rset, NULL, NULL, &tv);	
	int res = FD_ISSET(fd, &rset);
	//printf("read?? %d\n select ok?%d\n", res, result);
	
	return result;

}




int csSerialPort::Write(BYTE *buffer, int Length)
{
	int result = write(fd, buffer, Length);
	return result;
}





int csSerialPort::Close()
{
	return close(fd);
	 
}