Could someone help me with something like this? I wanted to add DS18N20 thermal sensor (http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf) via 1-wire interface and when I'm trying to connect it to ATZB-24-A2 (http://www.farnell.com/datasheets/1738045.pdf), which is using ATMEGA 1281 processor, this way
(source: tushev.org)
or this way
I'm receiving random bytes on COM terminal (I'm using FTDI chip). What could happen and how to fix it?
EDIT: I'm not even configuring anything in my software, it just starting mess without my interfere.
Best Answer
According to the datasheet, if you are powering the temperature sensor from an external supply, that supply must be connected to VDD. In your case you would wire directly from your 5V supply to pin 3 of each temperature sensor, bypassing the 4.7k resistor.
However, leaving the devices unpowered should not cause random bytes to be received. There are three possibilities I can think of: