I'm trying to pull analog input from a beaglebone black using this tutorial. However when I go to /sys/devices there is no cape-bone-iio. I have spoken with several other programmers and one of them suggested that the cape-bone does not work with the newer versions of Linux. However downgrading could have negative impact on the rest of the project. Is there any other solution?


2 Answers 2


I believe I encountered the exact same problem that you are encountering. The short/easy fix is downgrade your kernel. The newer kernel version (later than 3.8.x) for UbuntuARM does not use device tree overlays and stores all of these ADC values in god knows where.

You'll also notice that your tutorial is indeed using kernel 3.8.13. One that still involves device tree overlays and stores ADC values in the cape-bone-iio.

While it might not be exactly what you want, on my github I have a step by step approach to getting ADC values (as part of using ROS) on the BBB. This includes how to downgrade your kernel and enable Device Tree Overlays and then where the file locations for these values will be. I would recommend taking a look at it for some guidance towards your specific solution.

My Github

The steps for accomplishing this are directly on this page. I cannot post them directly due to a lack of reputation and the number of links the guide entails.

Another helpful hint, would be to specifically search for the name Robert C Nelson alongside Beaglebone Black. He has worked extensively with them and is involved in a multitude of blogs and tutorials that might help you find your solution.

Hope all of this helps.


I found the files for the analog inputs on the Beaglebone Black here:

/sys/devices/platform/ocp/44e0d000.tscadc/TI-am335x-adc.0.auto/iio:device0/in_voltage#_raw (where # is the pin number, 0 through 7)

Didn't downgrade my kernel. No enabling or setup needed. Those files are just continuously populated with the voltage readings from those pins. Values are 12 bit (0 to 4095, which corresponds to 0.0 volts to 1.8 volts).

Or at least this is how my Beaglebone Black works.


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