linux 串口操作_串口命令

linux串口通信编程 　　#include <unistd.h> #include <signal.h> #include <time.h> #include <fcntl.h> #include <string.h> #include <getopt.h> #include <errno.h> #include <termios.h> #include <stdio.h> #include <stdlib.h> #define UART_NAME “/dev/ttyS0” static int g_quit; static int g_speed; static void handle_signal(int sig) { if (SIGINT == sig || SIGTERM == sig) g_quit = 1; } static struct sigaction sigact = { .sa_handler = handle_signal, }; static struct option longopts[] = { {“help”, no_argument, NULL, ‘h’}, {“baudrate”, required_argument, NULL, ‘r’}, {0, 0, 0, 0}, }; static void print_usage(void) { fprintf(stdout, “usage: 　　”); fprintf(stdout, ” -r | –baudrate the serial baud rate 　　”); fprintf(stdout, ” -h | –help show this help and exit 　　”); } static int parse_arg(int argc, char argv) { int ret = 0; char c = ‘0’; while ( (c = getopt_long(argc, argv, “-:r:h”, longopts, NULL)) != -1) { switch (c) { case ‘r’: g_speed = atoi(optarg); break; case ‘h’: ret = -1; break; case ‘:’: fprintf(stdout, “%c require argument 　　”, optopt); ret = -1; break; case ‘?’: fprintf(stdout, “%c invalid argument 　　”, optopt); ret = -1; break; default: break; } } return ret; } static int uart_open(char *filename) { int fd; //fd = open(filename, O_RDWR); fd = open(filename, O_RDWR|O_NOCTTY|O_NDELAY); if (fd < 0) { printf(“%s %d: failed to open output file 　　”, __FILE__, __LINE__); return -1; } //nonblock if (fcntl(fd, F_SETFL, 0) < 0) { printf(“fcntl failed 　　”); close(fd); return -1; } return fd; } static int uart_set(int fd, int speed, int flow_ctrl, int databits, int parity, int stopbits) { struct termios options; int ret = 0; if (tcgetattr(fd, &options) != 0) { printf(“Setup serial fialed! 　　”); return -1; } int i; int speed_arr[] = {B, B, B, B, B, B, B, B, B, B57600, B38400, B19200, B9600, B4800, B2400, B1800, B1200, B600, B300, B200, B150, B134, B110, B75, B50, B0}; int name_arr[] = {, , , , , , , , , 57600, 38400, 19200, 9600, 4800, 2400, 1800, 1200, 600, 300, 200, 150, 134, 110, 75, 50, 0}; if (tcgetattr(fd, &options) != 0) { printf(“Setup serial fialed! 　　”); return -1; } printf(“speed = %d 　　”, speed); for (i = 0; i < sizeof(speed_arr) / sizeof(int); i++) { if (speed == name_arr[i]) { ret = cfsetispeed(&options, speed_arr[i]); if (ret) { perror(“cfsetispeed”); printf(“set in speed failed 　　”); } ret = cfsetospeed(&options, speed_arr[i]); if (ret) { perror(“cfsetispeed”); printf(“set out speed failed 　　”); } break; } } options.c_cflag |= CLOCAL; options.c_cflag |= CREAD; switch (flow_ctrl) { case 0: // no flow control options.c_cflag &= ~CRTSCTS; break; case 1: // hardware flow control options.c_cflag |= CRTSCTS; break; case 2: //software flow control options.c_cflag |= IXON|IXOFF|IXANY; break; default: printf(“Unsupported flow control 　　”); return -1; } options.c_cflag &= ~CSIZE; switch (databits) { case 5: options.c_cflag |= CS5; break; case 6: options.c_cflag |= CS6; break; case 7: options.c_cflag |= CS7; break; case 8: options.c_cflag |= CS8; break; default: printf(“Unsupported databits! 　　”); return -1; } switch (parity) { case ‘n’: //no parity case ‘N’: options.c_cflag &= ~PARENB; options.c_iflag &= ~INPCK; break; case ‘o’: //odd parity case ‘O’: options.c_cflag |= (PARODD | PARENB); options.c_iflag &= INPCK; break; case ‘e’: //even parity case ‘E’: options.c_cflag |= PARENB; options.c_cflag &= ~PARODD; options.c_iflag |= INPCK; break; case ‘s’: //blank case ‘S’: options.c_cflag &= ~PARENB; options.c_iflag &= ~CSTOPB; break; default: printf(“Unsupported parity 　　”); return -1; } switch (stopbits) { case 1: options.c_cflag &= ~CSTOPB; break; case 2: options.c_cflag |= CSTOPB; break; default: printf(“Unsupported stop bits 　　”); return -1; } //mode options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); /*Input*/ options.c_oflag &= ~OPOST; /*Output*/ //wait_time: 0.1s; min char to read:1 options.c_cc[VTIME] = 1; options.c_cc[VMIN] = 1; //if data overflow, receive data, but not read tcflush(fd, TCIFLUSH); //save configuration if (tcsetattr(fd, TCSANOW, &options) != 0) { printf(“set serial error! 　　”); return -1; } return 0; } static int recv_data(int fd, int fdtest) { int inflg = 0; int ret, size; int *data = NULL; do { if (g_quit) break; inflg = 0; ret = 0; size = 0; int hsize = read(fd, &size, 4); if (hsize < 0) { printf(“read header size error 　　”); ret = -1; break; } if (size <= 0) continue; printf(“size = %d 　　”, size); if (data) { free(data); data = NULL; } data = calloc(1, size); if (!data) { printf(“calloc failed 　　”); ret = -1; break; } int len = 0; int left_size = size – len; do { len = read(fd, data, left_size); if (len < 0) { printf(“read fd error 　　”); ret = -1; break; } //printf(“real read size = %d 　　”, len); int n = write(fdtest, data, len); if (n < 0) { printf(“write error! 　　”); ret = -1; break; } left_size = left_size – len; } while (left_size > 0); inflg = 1; } while (!inflg); if (data) { free(data); data = NULL; } return ret; } int main(int argc, char argv) { int ret = 0; int fd, fdtest; char send[1] = {‘a’}; ret = sigaction(SIGINT, &sigact, NULL); ret |= sigaction(SIGTERM, &sigact, NULL); if (ret) { printf(“%s line%d: %s 　　”, __FILE__, __LINE__, strerror(errno)); return -1; } g_speed = 9600; ret = parse_arg(argc, argv); if (ret) { print_usage(); return -1; } fd = uart_open(“/dev/ttyS0”); if (fd < 0) return -1; int speed = g_speed; int flow_ctrl = 0; int databits = 8; int stopbits = 1; int parity = ‘O’; ret = uart_set(fd, speed, flow_ctrl, databits, parity, stopbits); if (ret) { printf(“uart_set failed 　　”); goto out; } fdtest = open(“/mnt/recv.h264”, O_RDWR|O_SYNC); if (fdtest < 0) { printf(“open fdtest failed 　　”); goto out; } int n = write(fd, send, 1); if (n <= 0) { printf(“send a failed 　　”); close(fdtest); goto out; } do { if (g_quit) break; ret = recv_data(fd, fdtest); usleep(1000*10); send[0] = ‘b’; int res = write(fd, send, 1); if (res < 0) break; /* printf(“%s: %s: %d 　　”, __FILE__, __func__, __LINE__); */ } while (!ret); close(fdtest); out: close(fd); return ret; }