Digital Thermometer from One-Wire

[augustg]

Im using this device. DS18B20

http://www.pic_examples.byethost3.com/DS18B20.html

and I want to connect it to sbRIO. Since it is in digital, i'll need to connect it into digital input but how do I do that in FPGA? 

I connected it into analog input and it gives me negative and positive value interchangeably