Re: Dallas DS18B20 CRC


"suppamax" <max.giacometti@xxxxxxxxx> wrote in message
news:32a4a836-80e0-4659-b512-396e1062c2df@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I've got a problem using Dallas DS18s20 temperature sensor.
In particular, it seems to me it sends a wrong crc.

Here's how I use it.
Firstly, I perform a temperature conversion, and a second later I read
data stored in its scratchpad.
Data regarding temperature and fixed values seems correct (temperature
is correct, the other parameters are always the same), but the crc is
wrong.

What can I do to solve the problem?

Max,

How are you determining that the CRC is incorrect?
Is it possible that the bus master is incorrectly calculating what the CRC
should be?

Hard to say much else without more information. What hardware are you using
(microcontroller/microprocessor), how are you calculating CRC, etc?
There is apretty good writeup in the datasheet and Dallas (now Maxim)
application note AN27 covers CRC quite thoroughly.

Good luck,
Richard



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