我买了像

这样的板，现在我想把温度传感器连接到这个板上。如何用c或c++从传感器读取温度？我试着写一些代码，但它不起作用。我把DS18B20数据电缆直接连接到TXD和RXD引脚上。

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>
#include <cstring>
#include <inttypes.h>
#include <errno.h>

int
set_interface_attribs (int fd, int speed, int parity)
{
    struct termios tty;
    memset (&tty, 0, sizeof tty);
    if (tcgetattr (fd, &tty) != 0)
    {
            std::cout<<"error "<<errno<<" from tcgetattr";
            return -1;
    }

    cfsetospeed (&tty, speed);
    cfsetispeed (&tty, speed);

    tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8;     // 8-bit chars
    // disable IGNBRK for mismatched speed tests; otherwise receive break
    // as \000 chars
    tty.c_iflag &= ~IGNBRK;         // ignore break signal
    tty.c_lflag = 0;                // no signaling chars, no echo,
                                    // no canonical processing
    tty.c_oflag = 0;                // no remapping, no delays
    tty.c_cc[VMIN]  = 0;            // read doesn't block
    tty.c_cc[VTIME] = 5;            // 0.5 seconds read timeout

    tty.c_iflag &= ~(IXON | IXOFF | IXANY); // shut off xon/xoff ctrl

    tty.c_cflag |= (CLOCAL | CREAD);// ignore modem controls,
                                    // enable reading
    tty.c_cflag &= ~(PARENB | PARODD);      // shut off parity
    tty.c_cflag |= parity;
    tty.c_cflag &= ~CSTOPB;
    tty.c_cflag &= ~CRTSCTS;

    if (tcsetattr (fd, TCSANOW, &tty) != 0)
    {
        std::cout<<"error "<<errno<<" from tcsetattr";
            return -1;
    }
    return 0;
}

void
set_blocking (int fd, int should_block)
{
    struct termios tty;
    memset (&tty, 0, sizeof tty);
    if (tcgetattr (fd, &tty) != 0)
    {
        std::cout<<"error "<<errno<<" from tggetattr";
            return;
    }
    tty.c_cc[VMIN]  = should_block ? 1 : 0;
    tty.c_cc[VTIME] = 5;            // 0.5 seconds read timeout

    if (tcsetattr (fd, TCSANOW, &tty) != 0)
            std::cout<<"error "<<errno<<" setting term attributes";
}

int main()
{
        char *portname = "/dev/ttyUSB0";
        int tty_fd = open (portname, O_RDWR | O_NOCTTY | O_SYNC);
        if (tty_fd < 0)
        {
            std::cout<<"error "<<errno<<" opening "<<portname<<": "<< strerror (errno);
                return -1;
        }

        set_interface_attribs (tty_fd, B9600, 0);  // set speed to 115,200 bps, 8n1 (no parity)
        set_blocking (tty_fd, true);

        unsigned char c = 0xCC;
        if(!write(tty_fd, &c, sizeof(c)))
            std::cout<<"Write error";

        sleep(2);

        unsigned char buffer[8];
        int size;
        if((size = read(tty_fd, &buffer, 8)) < 0)
                std::cout<<"Error";
        else
            std::cout<<"CC("<<size<<")='"<<buffer<<"'";

        std::cout<<"\n";

        c = 0x44;
        if(!write(tty_fd, &c, sizeof(c)))
            std::cout<<"Write error2";

        c = 0xBE;
        if(!write(tty_fd, &c, sizeof(c)))
            std::cout<<"Write error2";

        sleep(2);

        if((size = read(tty_fd, &buffer, 8)) < 0)
                std::cout<<"Error";
        else
            std::cout<<"BE("<<size<<")='"<<buffer<<"'";

        std::cout<<"\n######################\n";

        close(tty_fd);
}

我得到了：

CC(1)='Č@'
BE(2)='@ž@'
######################
CC(1)='Č@'
BE(2)='@ž@'
######################
CC(1)='Č@'
BE(2)='@ž@'
######################

你能帮帮我吗？