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3 wire interface (GND, VCC, DATA)? Answered

Hi guys,  

I'm trying to reverse the communications on a project I have at the moment which seems to be using a 3 wire serial interface (GND, VCC, DATA).  My goal would be to replicate the communications with an arduino or similar, however i'm not 100% sure what serial protocol it's using.  
The device is using an Atmel ATMEGA168 and the pcb is covered in conformal coating, so I haven't had a whole lot of luck tracing the pins.
I'm not overly aware of many one-wire communications protocols.  The datasheet says the ATMEGA supports various peripheral features, including SPI, USART, 2-wire serial (Philips I2C) (among others), however the GND, VCC, DATA configuration doesn't seem to fit with any of the supported protocols (i.e. there's no clock line and only a single data line).  

The captures i'm getting seem to indicate that it's an 8-bit binary protocol.  I was going to try to decode it manually and attempt to reproduce it, however would be grateful if someone recognizes it and can point me in the right direction.

Does anyone know any protocols / configurations this could be?  Example screenshot attached.

Any help would be greatly appreciated!  Thanks!


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Best Answer 5 years ago

Probably Dallas "One Wire" looking at it.


Answer 5 years ago

Thanks Steve, I found this application note (http://www.atmel.com/images/doc2579.pdf) after posting my question. Seems Atmel support Dallas 1-wire over the U(S)ART interface, so your answer looks pretty accurate.

Thanks for the quick response!