i2c1 on the Beaglebone Black

Hello, I am also trying to get i2c working. I only require a single connection, so i dont know if i really to mess around with the kernel, and was kind of hoping to avoid it for now if possible. I purchased a 7-segment LED from Adafruit and am trying to get it working. They have a library for arduino but not much support for getting it working with BBB. So i soldered everything together, and have it connected to my breadboard and wired to my BBB. I found some handy info on various websites which got me far enough to find my device with i2cdetect. I am able to connect to p9_19 and p9_20 and then see my connection by doing

i2cdetect -r 1


which shows my new connection at 0x70. I then found the i2cdump command on yet another site and ran it,

i2cdump -y 1 0x70


and i got some hex data that i HARDLY know how to decipher, but when i ran the i2cdump command it caused my LED to light up! Exciting! It began flashing some alien-looking characters, but i could not figure out how to make it stop other than disconnecting the GND, and then it stops, and stayed off again when i reconnected my GND wire. So is my i2c-1 working properly? Do I have to write a program to interface with the LED or can I issue it commands to make it do stuff? What do i do next to make this thing show me the time, or a number that i choose, or ANYTHING useful, for that matter? I downloaded the arduino library that they have and read thru it a little bit, but i don’t know if i could PORT it…so i was hoping to just be able to issue a print command from a terminal and see an output. Can i do that? If not, can somebody point me in the right direction? Thanks…


Were you able to figure it out? I used the same i2cdump command on my LED 8x8 matrix and it’s flashing.

Im really not sure yet. I never got an answer to my question(s). I found this thread on the adafruit forums that has some helpful info for the 7-segment LEDs but i dont know how helpful itll be for the matrix ones.

Okay, thanks. I’ll check it out and hopefully I can figure it out. If I do, I’ll post a link on how to get it to work.

I got it working! I ended up using i2c commands to write onto the LED backpack. I’m going to write up a wiki on how I did it but here is what I did.

  1. Installed node i2c from here: https://github.com/korevec/node-i2c
  2. I programmed this code. To get it running, copy+paste this code on Cloud9 and run it. : https://dl.dropboxusercontent.com/u/9851737/8x8%20Bi-Color%20LED%20Matrix.txt