Wrong I2C bus

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Wrong I2C bus

Postby JoJoModding » Sat Dec 09, 2017 5:07 pm

Hello,
I'm trying to access a sensor via I2C on my Raspberry PI 2 B. However I'm not sure that I have enabled I2C correctly. Every tutorial online says that I should see the device when I run "i2cdetect -y 0", however that just gives:
Code: Select all
Error: Could not open file `/dev/i2c-0' or `/dev/i2c/0': No such file or directory


So apparently the i2c-0 bus isn't there. What is there however is i2c-2 and i2c-3. Running "i2cdetect -l" gives me this:
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i2c-3   i2c             soc:i2cdsi                              I2C adapter
i2c-2   i2c             bcm2835 I2C adapter                     I2C adapter


Running i2cdetect on bus 2 or 3 does not show the sensor (or any device at all), although it must be there somewhere. I have triple-checked my wiring.
Thanks for your help.
JoJoModding
 
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Re: Wrong I2C bus

Postby andre » Sun Dec 10, 2017 5:15 pm

Have you configured the correct device tree overlay in config.txt?
https://elinux.org/RPiconfig#Device_Tree
https://github.com/raspberrypi/firmware ... ays/README

Have you placed pull up (4K7) resistors to 3V3 on both SDA and SCL lines?
Is the speed you are using supported by the I2C sensor?
andre
 
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Location: Eindhoven


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