linux下uart编写

执行

./uart  /dev/ttySX 115200  8  0  1

代码

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

int read_data(int fd, void *buf, int len);
int write_data(int fd, void *buf, int len);
int setup_port(int fd, int baud, int databits, int parity, int stopbits);
void print_usage(char *program_name);

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t data_ready = PTHREAD_COND_INITIALIZER;
int data_available = 0;

void *read_thread(void *arg) {
    int fd = *(int *)arg;
    char buffer[1024]; // 存储读取的数据

    while (1) {
        int bytes_read = read_data(fd, buffer, sizeof(buffer));
        if (bytes_read > 0) {
            printf("Read Thread: Read %d bytes: %s\n", bytes_read, buffer);
        } else {
            // 处理读取错误或设备关闭的情况
            break;
        }
    }
    
    pthread_exit(NULL);
}

void *write_thread(void *arg) {
    int fd = *(int *)arg;
	char input[1024]; // 存储用户输入的数据

    while (1) {
        printf("Enter data to write (or 'q' to quit): ");
        fgets(input, sizeof(input), stdin);

        if (strcmp(input, "q\n") == 0 || strcmp(input, "Q\n") == 0) {
            // 用户输入 'q' 或 'Q'，退出循环
            break;
        }

        int len = strlen(input);
        int bytes_written = write_data(fd, input, len);
        if (bytes_written > 0) {
            printf("Write Thread: Wrote %d bytes: %s\n", bytes_written, input);
        }
    }
    
    pthread_exit(NULL);
}

int main(int argc, char *argv[]) 
{
    int fd;
    int baud;
    int len;
    int count;
    int i;
    int databits;
    int stopbits;
    int parity;

    if (argc != 6) {
        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;
    }
 
 
    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;
    }
	pthread_t read_tid, write_tid;
    int ret;

    // 创建读取线程
    ret = pthread_create(&read_tid, NULL, read_thread, &fd);
    if (ret != 0) {
        fprintf(stderr, "Failed to create read thread\n");
        return 1;
    }

    // 创建写入线程
    ret = pthread_create(&write_tid, NULL, write_thread, &fd);
    if (ret != 0) {
        fprintf(stderr, "Failed to create write thread\n");
        return 1;
    }

    // 等待读取线程和写入线程结束
    pthread_join(read_tid, NULL);
    pthread_join(write_tid, NULL);
	
    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
};

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;

int setup_port(int fd, int baud, int databits, int parity, int stopbits)
{
    struct termio term_attr;
 
    
    if (ioctl(fd, TCGETA, &term_attr) < 0) {
        return -1;
    }
 
    
    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);
 
    
    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;
    }
 
    
    switch (parity) {
        case 1:  
            term_attr.c_cflag |= (PARENB | PARODD);
            break;
 
        case 2:  
            term_attr.c_cflag |= PARENB;
            term_attr.c_cflag &= ~(PARODD);
            break;
 
        case 0:  
        default:
            term_attr.c_cflag &= ~(PARENB);
            break;
    }
 
 
    
    switch (stopbits) {
        case 2:  
            term_attr.c_cflag |= CSTOPB;
            break;
 
        case 1:  
        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;
}
 
 
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;
}
 
 
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;
}

void print_usage(char *program_name)
{
    fprintf(stderr,
            "*************************************\n"
            "  A Simple Serial Port Test Utility\n"
            "*************************************\n\n"
            "Usage:\n  %s      \n"
            "       databits: 5, 6, 7, 8\n"
            "       parity: 0(None), 1(Odd), 2(Even)\n"
            "       stopbits: 1, 2\n"
            "Example:\n  %s /dev/ttyS4 115200 8 0 1\n\n",
            program_name, program_name
           );
}