DS18B20 temp sensor IC

[makiyoung]

DS18B20 temp sensor IC Dq pin is connected to PSEN of controller in my application.

But in datasheet its mentioned that its connected to I/O port.

And second doubt is how I/O port senses temp? It should be connected to ADC pin of controller.

[JenniferT]

DS18B20 is a digital Thermometer, therefore you don't need any ADC. DS18B20 communicates with microcontroller through 1-wire protocol. You can also implement 1-wire protocol using GPIO.