DS18B20系列

2.  

int read_temperature(int portnum, float *current_temp, u16 *usData)
{
  int count=0, i;
  uchar family_id[MAXDEVICES][8], temp_H, temp_L;
  char str[100];

    owFamilySearchSetup(portnum, 0x00);
    while (owNext(portnum, TRUE, FALSE)) {
        count++;    //一定放于此,

    owSerialNum(portnum, family_id[count], TRUE);
    //array_hex(str, &family_id[count], 8);
    //DBG("%d: %s\n", count, str);

#if 1
        if (ReadTemperature(portnum, family_id[count], current_temp, usData)) {
        DBG(", Temperature = %5.1f, %5.1f \n", *current_temp, (*current_temp) * 9 / 5 + 32);
    }
    else
        DBG("Error reading temperature, verify device present:%d\n", (int)owVerify(portnum, FALSE));

#else
        owTouchReset(portnum);
        owTouchByte(portnum, 0xcc);
        owTouchByte(portnum, 0x44);    //所有的传感器开始转换温度
        msDelay(1000);

        owTouchReset(portnum);
        owTouchByte(portnum, 0x55);    //发送ROM匹配命令
        for(i=0; i<8; i++)
            owTouchByte(portnum, family_id[count]);

        owTouchByte(portnum, 0xBE);    //读温度寄存器(共可读9个寄存器)前两个是温度
        msDelay(20);

        temp_L = owTouchByte(portnum, 0xff); //读取温度的低位, F2 01, F4 01, FE 01
        temp_H = owTouchByte(portnum, 0xff); //读取温度的高位.
        current_temp = (temp_H*256 + temp_L)*0.0625;
        DBG(", %02X-%02X = %5.1f, %5.1f \n", temp_L, temp_H, current_temp, current_temp * 9 / 5 + 32);
#endif
  }

  owTouchReset(portnum);

    return 1;
}