| commit | author | age | ||
| 1e563e | 1 | /********************************************************************************* |
| G | 2 | * Copyright: (C) 2024 LingYun IoT System Studio |
| 3 | * All rights reserved. | |
| 4 | * | |
| 5 | * Filename: ttyS_test.c | |
| 6 | * Description: This file is comport loop back test program | |
| 7 | * | |
| 8 | * Version: 1.0.0(05/24/2024) | |
| 9 | * Author: Guo Wenxue <guowenxue@gmail.com> | |
| 10 | * ChangeLog: 1, Release initial version on "05/24/2024 07:38:43 PM" | |
| 11 | * | |
| 12 | ********************************************************************************/ | |
| 13 | ||
| 14 | #include <stdio.h> | |
| 15 | #include <stdlib.h> | |
| 16 | #include <string.h> | |
| 17 | #include <unistd.h> | |
| 18 | #include <fcntl.h> | |
| 19 | #include <errno.h> | |
| 20 | #include <termios.h> | |
| 21 | #include <pthread.h> | |
| 22 | ||
| 23 | #define DEV_NAME "/dev/ttymxc1" | |
| 24 | #define MSG "Hello, LingYun IoT System Studio!" | |
| 25 | ||
| 26 | int main(int argc, char **argv) | |
| 27 | { | |
| 28 | struct termios tty; | |
| 29 | int serial_fd; | |
| 30 | int bytes; | |
| 31 | char read_buf[64]; | |
| 32 | ||
| 33 | /*+-------------------------+ | |
| 34 | | Open Serial Port | | |
| 35 | +-------------------------+*/ | |
| 36 | serial_fd = open(DEV_NAME, O_RDWR ); | |
| 37 | if (serial_fd == -1) | |
| 38 | { | |
| 39 | printf("Open '%s' failed: %s\n", DEV_NAME, strerror(errno)); | |
| 40 | return 0; | |
| 41 | } | |
| 42 | ||
| 43 | /*+-------------------------+ | |
| 44 | | Configure Serial Port | | |
| 45 | +-------------------------+*/ | |
| 46 | ||
| 47 | tcgetattr(serial_fd, &tty);// read current serial port settings | |
| 48 | ||
| 49 | tty.c_cflag &= ~PARENB; // Clear parity bit, disabling parity (most common) | |
| 50 | tty.c_cflag &= ~CSTOPB; // Clear stop field, only one stop bit used in communication (most common) | |
| 51 | tty.c_cflag &= ~CSIZE; // Clear all bits that set the data size | |
| 52 | tty.c_cflag |= CS8; // 8 bits per byte (most common) | |
| 53 | tty.c_cflag &= ~CRTSCTS; // Disable RTS/CTS hardware flow control (most common) | |
| 54 | tty.c_cflag |= CREAD | CLOCAL; // Turn on READ & ignore ctrl lines (CLOCAL = 1) | |
| 55 | ||
| 56 | tty.c_lflag &= ~ICANON; | |
| 57 | tty.c_lflag &= ~ECHO; // Disable echo | |
| 58 | tty.c_lflag &= ~ECHOE; // Disable erasure | |
| 59 | tty.c_lflag &= ~ECHONL; // Disable new-line echo | |
| 60 | tty.c_lflag &= ~ISIG; // Disable interpretation of INTR, QUIT and SUSP | |
| 61 | tty.c_iflag &= ~(IXON | IXOFF | IXANY); // Turn off s/w flow ctrl | |
| 62 | tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL); // Disable any special handling of received bytes | |
| 63 | ||
| 64 | tty.c_oflag &= ~OPOST; // Prevent special interpretation of output bytes (e.g. newline chars) | |
| 65 | tty.c_oflag &= ~ONLCR; // Prevent conversion of newline to carriage return/line feed | |
| 66 | ||
| 67 | tty.c_cc[VTIME] = 10; // Wait for up to 1s (10 deciseconds), returning as soon as any data is received. | |
| 68 | tty.c_cc[VMIN] = 0; | |
| 69 | ||
| 70 | /* Set in/out baud rate to be 115200 */ | |
| 71 | cfsetispeed(&tty, B115200); | |
| 72 | cfsetospeed(&tty, B115200); | |
| 73 | ||
| 74 | tcsetattr(serial_fd, TCSANOW, &tty); | |
| 75 | ||
| 76 | /*+-------------------------+ | |
| 77 | | Write to Serial Port | | |
| 78 | +-------------------------+*/ | |
| 79 | write(serial_fd, MSG, strlen(MSG)); | |
| 80 | printf("Send MSG : %s\n", MSG); | |
| 81 | ||
| 82 | /*+-------------------------+ | |
| 83 | | Read from Serial Port | | |
| 84 | +-------------------------+*/ | |
| 85 | /* | |
| 86 | * The behaviour of read() (e.g. does it block?, how long does it block for?) | |
| 87 | * depends on the configuration settings above, specifically VMIN and VTIME | |
| 88 | */ | |
| 89 | memset(&read_buf, '\0', sizeof(read_buf)); | |
| 90 | bytes = read(serial_fd, &read_buf, sizeof(read_buf)); | |
| 91 | if (bytes< 0) | |
| 92 | { | |
| 93 | printf("Error reading: %s", strerror(errno)); | |
| 94 | goto cleanup; | |
| 95 | } | |
| 96 | ||
| 97 | printf("Received MSG: %s\n", read_buf); | |
| 98 | ||
| 99 | /*+-------------------------+ | |
| 100 | | close Serial Port | | |
| 101 | +-------------------------+*/ | |
| 102 | ||
| 103 | cleanup: | |
| 104 | close(serial_fd); | |
| 105 | return 0; // success | |
| 106 | } | |
