LINUX_RS232/RS485通信

#include <stdio.h>
#include <pthread.h>
#include “RS485.h”

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <termios.h>
#include <linux/serial.h>
#include <sys/ioctl.h>
#include <sys/utsname.h>
#include <stdint.h>

/**

• @brief: set the properties of serial port
• @Param: fd: file descriptor
• @Param: nSpeed: Baud Rate
• @Param: nBits: character size
• @Param: nEvent: parity of serial port
• @Param: nStop: stop bits
  */

typedef enum {DISABLE = 0, ENABLE} RS485_ENABLE_t;

int Set_Uart(int fd, int nSpeed, int nBits, char nEvent, int nStop)
{
struct termios newtio, oldtio;

memset(&oldtio, 0, sizeof(oldtio));
/* save the old serial port configuration */
if(tcgetattr(fd, &oldtio) != 0) {
	perror("set_port/tcgetattr");
	return -1;
}

memset(&newtio, 0, sizeof(newtio));
/* ignore modem control lines and enable receiver */
newtio.c_cflag = newtio.c_cflag |= CLOCAL | CREAD;// 开启读取模式和本地连接模式
newtio.c_cflag &= ~CSIZE;// 数据位掩码
/* set character size */
switch (nBits) {
	case 8:
		newtio.c_cflag |= CS8;// 8个数据位
		break;
	case 7:
		newtio.c_cflag |= CS7;
		break;
	case 6:
		newtio.c_cflag |= CS6;
		break;
	case 5:
		newtio.c_cflag |= CS5;
		break;
	default:
		newtio.c_cflag |= CS8;
		break;
}
/* set the parity */ 
switc