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One Wire DS18B20

Posted: Wed Sep 15, 2010 9:07 pm
by trisb
Hi Guys.

I have been trying to understand and learn how to use the one wire function. Being new to Flowcode and Micro chips, I am not doing to well.

I am trying to use this with a DS18B20.
At the moment i have taken the One Wire Example form the Example pack and have changed the relevant Custom code for the One Wire.

How ever when I connect up my sensor I am unable to get the correct temp to display and get 85.0 on my display.
I have also been getting this with other examples i have been looking at and found on the forum.

I am running this in a Pic16F887a
with the sensor On port A0. i have tried with the VDD pin connected to GND & with the Data pin connected with a 4K7 resistor to the v5 line of my board.

I have attached the code for you to look at as i might of missed some thing..

any help would be very much appreciated

Thanks

Tristan

Re: One Wire DS18B20

Posted: Thu Sep 16, 2010 11:26 am
by Jan Lichtenbelt
Dear Tristian,

The 85 C reading means is the default temperature of the sensor. This means part of your setup is working correctly. What is wrong, software of hardware, can be checked by using a working software of Ben
http://www.matrixmultimedia.com/mmforum ... B20#p15709

Good luck

Jan

Re: One Wire DS18B20

Posted: Thu Sep 16, 2010 2:39 pm
by trisb
Thanks Jan,

Looks like have found my problem....

I have 2 Bad Sensors. found a 3 sensor and plugged it in and i am getting a reading.

Thanks