Help with I2C on BBB in Debian

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Joshua Datko

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Oct 26, 2013, 2:38:27 PM10/26/13
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In the default Debian imagine, can any I2C bus be used from the P9 expansion header, without rebuilding the kernel?  If so, which pins?  (19 & 20, or 17 & 18?)

When I run i2cdetect, I have two I2C buses, but I'm not sure which buses they map to on the BBB:

i2c-0 i2c OMAP I2C adapter I2C adapter 
i2c-1 i2c OMAP I2C adapter I2C adapter

Assuming I have a working I2C slave device, if I wire SDA to P9_20, SCL to P9_19, 3.3V power to P9_3, GND to P9_1, would one expect the device to show up on the i2c bus (the breakout board already has a pull-up resistor)?

Josh

may...@magsoft.com.br

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Oct 27, 2013, 10:50:32 AM10/27/13
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The Debian maps the i2c-0 to i2c0, and i2c-1 to i2c2, if you use
echo BB-I2C2 > /sys/devices/bone_capemgr.????/slots
this enables i2c-2 maped to i2c1 on BBB in all cases the bus is configured with pull-ups, be careful with
capacitance in line, long wires can add...
i2c0 - internal
i2c1 - pins 17-18
i2c2 - pins 19-20
Maycon

may...@magsoft.com.br

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Oct 27, 2013, 10:53:50 AM10/27/13
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Sory, please read...
echo BB-I2C1 > /sys/devices/bone_capemgr.????/slots
Maycon

Joshua Datko

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Oct 31, 2013, 7:16:06 PM10/31/13
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Thanks Maycon,

That did the trick.

Josh


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smith.wi...@gmail.com

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Nov 1, 2013, 12:48:54 PM11/1/13
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On Saturday, October 26, 2013 2:38:27 PM UTC-4, Joshua Datko wrote:

In the default Debian imagine, can any I2C bus be used from the P9 expansion header, without rebuilding the kernel?  If so, which pins?  (19 & 20, or 17 & 18?)

When I run i2cdetect, I have two I2C buses, but I'm not sure which buses they map to on the BBB:

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