How to set pin mode BeagleBone Black

Question

linux

I want to ask for help. I have a Beaglebone Black. I can't change the Mode for the GPIO.

That is, for example, I connect the LED to those GPIOs that are configured as GPIOs (for example, P8_8 - GPIO67), everything works, but if I connect to those GPIOs that are configured, for example, as an HDMI pin, then naturally nothing works.

I found that in an older version of the kernel it was possible to change the mode with the command:

echo 7 > /sys/kernel/debug/omap_mux/gpmc_ad4.

But it doesn't work in the new kernel "The above only works if you're using the older kernel. The new 3.8 based kernel is missing this nifty pin mux feature."

I found "Setup for Device Tree Overlays" but I can't figure out how it works and what needs to be done to change the Mode

http://derekmolloy.ie/gpios-on-the-beaglebone-black-using-device-tree-overlays/

Maybe someone else has had a similar problem and can give some advice/advice.

Answer 1

Unfortunately right now from the phone, I can not give links. I recently received this device myself. somewhere in the docks or on the network, I don’t remember exactly, I saw something like this: in order to use pins that are clearly tied to the periphery on the board, you need to explicitly tell the system that we are refusing hdmi for example. I'll try to google now...

By the way, which distro did you decide to install? and what are you using it for?

Answer 2

Hello.
Thanks for your help. First, I updated the board with the latest firmware, and then did everything as indicated in the article.

http://www.logicsupply.com/blog/2013/07/18/disabling-the-beaglebone-black-hdmi-cape/

Then I successfully checked that HDMI was disabled and successfully configured GPIO70 and 71 (P8 -45 and 46 pin).