Forum rules
Talk about Adafruit Raspberry Pi® accessories! Please do not ask for Linux support, this is for Adafruit products only! For Raspberry Pi help please visit: http://www.raspberrypi.org/phpBB3/

quick question about the Matrix.. Backpack learning module

by blave on Tue Nov 06, 2012 10:07 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
User avatar
blave
 
Posts: 13
Joined: Tue Jul 14, 2009 8:32 pm

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

by blave on Fri Nov 09, 2012 8:13 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.
User avatar
blave
 
Posts: 13
Joined: Tue Jul 14, 2009 8:32 pm