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quick question about the Matrix.. Backpack learning module
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quick question about the Matrix.. Backpack learning module

by blave on Tue Nov 06, 2012 11:07 pm

I think I have all of this hooked up correctly, but using i2cdetect doesn't show anything, and looking in /dev doesn't reveal any i2c* devices.

I'm assuming the project is powering the i2c backpack/8x8 matrix with the Cobbler's 3V3 connection. Am I wrong? Am I supposed to use a separate PS to power the backpack/display?

BTW I'm powering the Pi with a Kindle power supply, which is theoretically 800mA. I am wondering if it can't keep up with the combination of Pi/USB wireless adaptor/backpack-LED display.

This is my first test of the Cobbler -- maybe I should just try lighting up a single LED 8^) .

thanks,

Dave B.
San Jose, CA
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Re: quick question about the Matrix.. Backpack learning module

by blave on Fri Nov 09, 2012 9:13 pm

Answering my own post: i2c is not enabled in Raspbian Wheezy. I had to add the following lines to /etc/modules:

i2c-dev
i2c-bcm2708

After rebooting I had /dev/i2c-0 and i2c-1, and everything works now.


Dave.
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