Giao tiếp 1-wire DS18b20

[ngocnhat95]

Ai đã làm vs DS18b20 rồi kiểm tra giúp em , đoạn code của e sai chỗ nào được ko ak. sao giá trị hàm ds18b20_read() thu được cứ =0 thôi ak

void onewire_write(int8 data) {
   unsigned  int8 count;

    for(count = 0; count < 8; ++count) {
        output_low(ONE_WIRE_PIN);
        delay_us(2);                // pull 1-wire low to initiate write time-slot.
        output_bit(ONE_WIRE_PIN, shift_right(&data, 1, 0)); // set output bit on 1-wire
        delay_us(60);               // wait until end of write slot.
        output_float(ONE_WIRE_PIN); // set 1-wire high again,
        delay_us(2);                // for more than 1us minimum.
    }
}

/*
 * onewire_read()
 * Description: reads and returns a byte of data from the device.
 */
int8 OneWire_Read()
{
 int8 count, data=0;

 for (count=0; count<8; ++count)
 {
  output_low(ONE_WIRE_PIN);//Thiet lap dau ra
  ONE_WIRE_PIN=0;
  delay_us( 2 );                      
  input(ONE_WIRE_PIN);//Thiet lap dau vao         
  delay_us( 8 );                
  if(ONE_WIRE_PIN)
  data|=0x01<<count;
  delay_us( 120 ); 
 }
 return( data );
} 

 
float ds18b20_read() {
    int8  temp1, temp2;
    signed int16 temp3;
    float result;

    onewire_reset();
    onewire_write(0xCC);            //Skip ROM, address all devices
    onewire_write(0x44);            //Start temperature conversion
    delay_us(200);
    onewire_reset();
    onewire_write(0xCC);            //Skip ROM, address all devices
    onewire_write(0xBE);            //Read scratchpad
    temp1 = onewire_read();
    temp2 = onewire_read();
    temp3 = make16(temp2, temp1);
 
    //result = (float) temp3 / 2.0;   //Calculation for DS18S20 with 0.5 deg C resolution
    result = (float) temp3 / 16.0;    //Calculation for DS18B20 with 0.1 deg C resolution 
 
    delay_ms(200);     // ??????
    return (result);
}


void ds18b20_configure(int8 TH, int8 TL, int8 config) {
    onewire_reset();
    onewire_write(0xCC);            //Skip ROM, address all devices
    onewire_write(0x4E);            //Write to scratchpad
    onewire_write(TH);
    onewire_write(TL);
    onewire_write(config);
}