BeagleBone: read rotary encoder position using built-in TI eQEP hardware module
Channel: Drew Fustini
Date: 12/07/2014

BeagleBoard.org Project Page: http://beagleboard.org/project/eqep_rotary_encoder/
I demonstrate how to read position of a rotary encoder connected to the BeagleBone Black.  I use the eQEP (enhanced Quadrature-Encoded Pulse) decoder module built-in to the BBB's TI Sitara ARM processor.
NOTE: This requires the TI eQEP Linux kernel module from Nathiel Lewis (http://nathanielrlewis.com/?p=87) which is inlcuded on BeagleBoard.org Debian image for BBB since 2014-May-14 (http://beagleboard.org/latest-images)
Further information on the eQEP kernel module and API for Python & C++ is in Nathaniel's GitHub repo: https://github.com/Teknoman117/beaglebot/tree/master/encoders
The Device Tree Overlay file bone_eqep2b-00A0.dtbo that I mention in the video is located in my GitHub repo: https://github.com/pdp7/beaglebot/tree/master/encoders/dts/dtbo
For reference, here are GitHub Gist text files that I created as notes while making the video:
https://gist.github.com/pdp7/eb34f4eaeee8ba078177
https://gist.github.com/pdp7/31e31a9262413af961ad
https://gist.github.com/pdp7/8a8fb9e2d2e1aef232d2
https://gist.github.com/pdp7/8241f151c1b9b781f6ea