前言：
#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <termios.h> #include <errno.h> #include <sys/poll.h> #include <sys/ioctl.h> #include <string.h> #define UART_DEVICE_NAME "/dev/tty96B0" #define BUF_LEN 256 static int fd = -1; //设置串口通信速率9600 设置串口数据位8，停止位1 和 效验位无 static int open_dev(char *dev_name) { struct termios opt; fd = open(dev_name, O_RDWR | O_NOCTTY | O_NONBLOCK); if (fd < 0) { perror("open"); return fd; } tcgetattr(fd, &opt); cfsetispeed(&opt, B9600); cfsetospeed(&opt, B9600); if(tcsetattr(fd, TCSANOW, &opt) != 0 ) { perror("tcsetattr error"); return -1; } opt.c_cflag &= ~CSIZE; opt.c_cflag |= CS8; opt.c_cflag &= ~CSTOPB; opt.c_cflag &= ~PARENB; opt.c_cflag &= ~INPCK; opt.c_cflag |= (CLOCAL | CREAD); opt.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); opt.c_oflag &= ~OPOST; opt.c_oflag &= ~(ONLCR | OCRNL); //添加的 opt.c_iflag &= ~(ICRNL | INLCR); opt.c_iflag &= ~(IXON | IXOFF | IXANY); //添加的 opt.c_cc[VTIME] = 0; opt.c_cc[VMIN] = 0; tcflush(fd, TCIOFLUSH); printf("configure complete\n"); if(tcsetattr(fd, TCSANOW, &opt) != 0) { perror("serial error"); return -1; } return fd; } int main(int argc,char *argv[]) { int fd; int i; int len; int n = 0; char buf_uart[BUF_LEN],grade; int iRet = 0; float pm_value = 0; fd = open_dev(UART_DEVICE_NAME);//init uart and open uart if(fd == -1) { perror("open serial error\n"); exit(0); } printf("start send and receive data\n"); #if 1 struct pollfd read_poll[2]; read_poll[0].fd = fd; /* fd_uart */ read_poll[0].events = POLLIN; read_poll[0].revents = 0; read_poll[1].fd = 0; /* stdin */ read_poll[1].events = POLLIN; read_poll[1].revents = 0; while (1) { printf("waitting...\n"); iRet = poll(read_poll, 2, -1); if(iRet <= 0) { printf("nothing come\n"); continue; } //printf("comming a new input!\n"); if (read_poll[0].revents & POLLIN) { bzero(buf_uart, BUF_LEN); len = read(fd, buf_uart, BUF_LEN); buf_uart[len] = '\0'; if(len < 0) { perror("read"); exit(1); } pm_value = (int)buf_uart[3]+(int)buf_uart[4]*0.01; switch((int)pm_value/2) { case 0: grade = 'a'; break; case 1: grade = 'b'; break; case 2: grade = 'c'; break; case 4: grade = 'd'; break; } printf(" 当前空气质量： %4.2f %% %c \n", pm_value,grade); } }//while(1) kk_exit : close(fd); return 0; #endif }