Problem with the DS18B20 temperature sensor (NUCLEO-F401RE board )

Hello all,
I'm continuing my trip in the Espruino world and I'm experiencing a problem with the DS18B20 temperature sensor and my ST NUCLEO-F401RE board on which I uploaded the latest version of Espruino (1v93).
Using the first example shown on the DS18B20 sensor page (http://www.espruino.com/DS18B20) precisely:

var ow = new OneWire(A0);
var sensor = require("DS18B20").connect(ow);
setInterval(function() {
  sensor.getTemp(function (temp) {
    console.log("Temp is "+temp+"°C"); 
  });
}, 1000);

I get the following result (instead of temperature value):

_____                 _
|   __|___ ___ ___ _ _|_|___ ___
|   __|_ -| . |  _| | | |   | . |
|_____|___|  _|_| |___|_|_|_|___|
          |_| http://espruino.com
 1v93 Copyright 2016 G.Williams
Espruino is Open Source. Our work is supported
only by sales of official boards and donations:
http://espruino.com/Donate
>
=undefined
Temp is null°C
Temp is null°C
Temp is null°C
Temp is null°C

The DS18B20 "cabled sensor" type is that identified on the Espruino web page as "Sensor type 1" connected as follows:

Black wire -> GND
Red wire -> 3.3V
Yellow wire -> Data pin (A0)

I'm also using the 4.7k resistor between data and the 3.3v line as suggested.

Browsing in the forum before posting the question I noticed the following post:
http://forum.espruino.com/conversations/­254655/#comment11813806

in which Gordon suggested to skip the DS18B20 module and search for the sensor through the OneWire protocol.
In the same configuration (board+sensor), described above, I get the following result:

>var ow = new OneWire(A0);
=OneWire { "pin": A0 }
>ow.search(); // should return an array of devices
=[
  "28ff050b85160520"
 ]
> 

It seems to recognize the serial number of the DS18B20 device...

Could you please help me to solve this issue?
Thanks in advance for your support.
Kind regards