I test this library on Arduino Nano, when I connected the data pin of DS18B20 to A7(D21), it would show "-127" in Serial Monitor by "Serial.print();", when changed A7 to D4, the showing is correct. When I want to print the temperature on OLED by "oled.print();" from this library, it always show "-127" either D21 or D4, D5, A0 ... why?