DM6446的Linux串口测试程序

Linux串口测试程序

冷胜魁(Seaquester)
[e-mail]
2009-11-18

这是以前在做一个基于ARM的项目的时候，写的一个简单串口测试程序，同样也适用于X86平台16C550串口。程序很简单，运行是通过参数指定程序是发送端还是接收端。接收端运行之后就简单的读取串口数据，打印到stdout。发送端则接受键盘输入，通过串口发送出去。如果直接回车则表示发送完毕，通知接收端退出。

/****************************************************************************** * * FILENAME: * testcom.c * * DESCRIPTION: * A utility to read/write serial port * Usage: testcom <device> <baud> <databits> <parity> <stopbits> <read_or_write> * databits: 5, 6, 7, 8 * parity: 0(None), 1(Odd), 2(Even) * stopbits: 1, 2 * read_or_write: 0(read), 1(write) * Example: testcom /dev/ttyS0 9600 8 0 1 0 * * REVISION(MM/DD/YYYY): * 03/12/2008 Shengkui Leng ([e-mail]) * - Initial version * ******************************************************************************/#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <unistd.h>#include <fcntl.h>#include <string.h>#include <termio.h>#include <time.h>#define MAX_BUF_SIZE 2048char buf[MAX_BUF_SIZE+2];#define MY_END_CHAR 0x13int setup_port(int fd, int baud, int databits, int parity, int stopbits);int reset_port(int fd);int read_data(int fd, void *buf, int len);int write_data(int fd, void *buf, int len);void print_usage(char *program_name);int main(int argc, char *argv[]){    int fd;    int baud;    int len;    int count;    int i;    int databits;    int stopbits;    int parity;    int read_or_write;    if (argc != 7) {        print_usage(argv[0]);        return 1;    }    baud = atoi(argv[2]);    if ((baud < 0) || (baud > 921600)) {        fprintf(stderr, "Invalid baudrate!\n");        return 1;    }    databits = atoi(argv[3]);    if ((databits < 5) || (databits > 8)) {        fprintf(stderr, "Invalid databits!\n");        return 1;    }    parity = atoi(argv[4]);    if ((parity < 0) || (parity > 2)) {        fprintf(stderr, "Invalid parity!\n");        return 1;    }    stopbits = atoi(argv[5]);    if ((stopbits < 1) || (stopbits > 2)) {        fprintf(stderr, "Invalid stopbits!\n");        return 1;    }    read_or_write = atoi(argv[6]);    fd = open(argv[1], O_RDWR, 0);    if (fd < 0) {        fprintf(stderr, "open <%s> error %s\n", argv[1], strerror(errno));        return 1;    }    if (setup_port(fd, baud, databits, parity, stopbits)) {        fprintf(stderr, "setup_port error %s\n", strerror(errno));        close(fd);        return 1;    }    count = 0;    if (read_or_write) {        fprintf(stderr, "Begin to send:\n");        while ( (len = read(0, buf, MAX_BUF_SIZE)) > 0 ) {            if (len == 1) {                buf[0] = MY_END_CHAR;                buf[1] = 0;                write_data(fd, buf, len);                break;            }            /* send a pack */            i = write_data(fd, buf, len);            if (i == 0) {                fprintf(stderr, "Send data error!\n");                break;            }            //count += len;            //fprintf(stderr, "Send %d bytes\n", len);        }    } else {        fprintf(stderr, "Begin to recv:\n");        len = MAX_BUF_SIZE;        while (1) {            /* read a pack */            i = read_data(fd, buf, len);            if (i > 0) {                //count += i;                //fprintf(stderr, "Recv %d byte\n", i);                printf("%s", buf);                if (buf[i-1] == MY_END_CHAR) {                    break;                }            }        }    }    reset_port(fd);    close(fd);    return 0;}static int baudflag_arr[] = {    B921600, B460800, B230400, B115200, B57600, B38400,    B19200, B9600, B4800, B2400, B1800, B1200,    B600, B300, B150, B110, B75, B50};static int speed_arr[] = {    921600, 460800, 230400, 115200, 57600, 38400,    19200, 9600, 4800, 2400, 1800, 1200,    600, 300, 150, 110, 75, 50};/****************************************************************************** * NAME: * speed_to_flag * * DESCRIPTION: * Translate baudrate into flag * * PARAMETERS: * speed - The baudrate to convert * * RETURN: * The flag ******************************************************************************/int speed_to_flag(int speed){    int i;    for (i = 0; i < sizeof(speed_arr)/sizeof(int); i++) {        if (speed == speed_arr[i]) {            return baudflag_arr[i];        }    }    fprintf(stderr, "Unsupported baudrate, use 9600 instead!\n");    return B9600;}static struct termio oterm_attr;/****************************************************************************** * NAME: * stup_port * * DESCRIPTION: * Set serial port (include baudrate, line control) * * PARAMETERS: * fd - The fd of serial port to setup * baud - Baudrate: 9600, ... * databits - Databits: 5, 6, 7, 8 * parity - Parity: 0(None), 1(Odd), 2(Even) * stopbits - Stopbits: 1, 2 * * RETURN: * 0 for OK; Others for ERROR ******************************************************************************/int setup_port(int fd, int baud, int databits, int parity, int stopbits){    struct termio term_attr;    /* Get current setting */    if (ioctl(fd, TCGETA, &term_attr) < 0) {        return -1;    }    /* Backup old setting */    memcpy(&oterm_attr, &term_attr, sizeof(struct termio));    term_attr.c_iflag &= ~(INLCR | IGNCR | ICRNL | ISTRIP);    term_attr.c_oflag &= ~(OPOST | ONLCR | OCRNL);    term_attr.c_lflag &= ~(ISIG | ECHO | ICANON | NOFLSH);    term_attr.c_cflag &= ~CBAUD;    term_attr.c_cflag |= CREAD | speed_to_flag(baud);    /* Set databits */    term_attr.c_cflag &= ~(CSIZE);    switch (databits) {        case 5:            term_attr.c_cflag |= CS5;            break;        case 6:            term_attr.c_cflag |= CS6;            break;        case 7:            term_attr.c_cflag |= CS7;            break;        case 8:        default:            term_attr.c_cflag |= CS8;            break;    }    /* Set parity */    switch (parity) {        case 1: /* Odd parity */            term_attr.c_cflag |= (PARENB | PARODD);            break;        case 2: /* Even parity */            term_attr.c_cflag |= PARENB;            term_attr.c_cflag &= ~(PARODD);            break;        case 0: /* None parity */        default:            term_attr.c_cflag &= ~(PARENB);            break;    }    /* Set stopbits */    switch (stopbits) {        case 2: /* 2 stopbits */            term_attr.c_cflag |= CSTOPB;            break;        case 1: /* 1 stopbits */        default:            term_attr.c_cflag &= ~CSTOPB;            break;    }    term_attr.c_cc[VMIN] = 1;    term_attr.c_cc[VTIME] = 0;    if (ioctl(fd, TCSETAW, &term_attr) < 0) {        return -1;    }    if (ioctl(fd, TCFLSH, 2) < 0) {        return -1;    }    return 0;}/****************************************************************************** * NAME: * read_data * * DESCRIPTION: * Read data from serial port * * * PARAMETERS: * fd - The fd of serial port to read * buf - The buffer to keep readed data * len - The max count to read * * RETURN: * Count of readed data ******************************************************************************/int read_data(int fd, void *buf, int len){    int count;    int ret;    ret = 0;    count = 0;    //while (len > 0) {    ret = read(fd, (char*)buf + count, len);    if (ret < 1) {        fprintf(stderr, "Read error %s\n", strerror(errno));        //break;    }    count += ret;    len = len - ret;    //}    *((char*)buf + count) = 0;    return count;}/****************************************************************************** * NAME: * write_data * * DESCRIPTION: * Write data to serial port * * * PARAMETERS: * fd - The fd of serial port to write * buf - The buffer to keep data * len - The count of data * * RETURN: * Count of data wrote ******************************************************************************/int write_data(int fd, void *buf, int len){    int count;    int ret;    ret = 0;    count = 0;    while (len > 0) {        ret = write(fd, (char*)buf + count, len);        if (ret < 1) {            fprintf(stderr, "Write error %s\n", strerror(errno));            break;        }        count += ret;        len = len - ret;    }    return count;}/****************************************************************************** * NAME: * print_usage * * DESCRIPTION: * print usage info * * PARAMETERS: * program_name - The name of the program * * RETURN: * None ******************************************************************************/void print_usage(char *program_name){    fprintf(stderr,            "*************************************\n"            " A Simple Serial Port Test Utility\n"            "*************************************\n\n"            "Usage:\n %s <device> <baud> <databits> <parity> <stopbits> <read_or_write>\n"            " databits: 5, 6, 7, 8\n"            " parity: 0(None), 1(Odd), 2(Even)\n"            " stopbits: 1, 2\n"            " read_or_write: 0(read), 1(write)\n"            "Example:\n %s /dev/ttyS0 9600 8 0 1 0\n\n",            program_name, program_name           );}/****************************************************************************** * NAME: * reset_port * * DESCRIPTION: * Restore original setting of serial port * * PARAMETERS: * fd - The fd of the serial port * * RETURN: * 0 for OK; Others for ERROR ******************************************************************************/int reset_port(int fd){    if (ioctl(fd, TCSETAW, &oterm_attr) < 0) {        return -1;    }    return 0;}