Help with I2C on BBB in Debian

GoogleGroups
1

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

2

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

3

Sory, please read…
echo BB-I2C1 > /sys/devices/bone_capemgr.???/slots
Maycon

4

Thanks Maycon,

That did the trick.

Josh

5

See:

https://groups.google.com/forum/#!msg/beagleboard/v9r8UkN7klk/h3rFKFJDLnUJ