i2c not detected

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gunjannigam
 
Posts: 1
Joined: Mon Feb 03, 2014 8:39 am

i2c not detected

Post by gunjannigam »

Hi,
I have 3 BBB boards and I am trying to communicate through I2C with my sensor SHT11. I have plugged the device on i2c 0 with VCC to pin P9_3, GND to pin P9_1, SCL to pin P9_17 and SDA to pin P9_18. When I run i2cdetect using i2cdetect -y -a -r 0
i get
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- UU -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- UU -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: UU -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

The response is same even if I disconnect my sensor.
I tried changing to channel 1 after making connections SCL to P9_19 and SCL to P9_20. Still the same response on i2cdetect -y -a -r 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- UU UU UU UU -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
I even tried changing the board but still the same response on all BBB. There is a pull up register on my sensor for i2c to work and I also have latest pyhton-smbus intalled. But I don't know why I am not able to detect any device. Do I need to enable anything else on my BBB for i2c to work??

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jstampfl
 
Posts: 25
Joined: Mon Sep 17, 2012 2:15 am

Re: i2c not detected

Post by jstampfl »

For an I2C example search this forum for "HMC5883L compass, C programming"

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