Issues with GPIO

Hi everybody!

I’m new on beagleboard, so please be understanding :slight_smile:

Well I’m trying to get GPIO working on a BeagleBoard. I followed a lot of How to on the net, but it doesn’t work:

  1. log on the board as root throught serial port
  2. I went in /sys/class/gpio, and type “echo 168 > export”. (168 correpsond to the port 24 according to the documentation)
  3. then I cd gpio168, and I did a “echo out > direction”.
  4. “cat value” return 0
  5. then I got the voltage with a multimeter, between pin 27 and pin 24: 1.8V (it’s a high level)

On IRC, someone said that I have to set the muxing. To do that, I have to look in the /sys/kernel/debug. This is the output of ls command:

root@beagleboard:/sys/kernel/debug# ls asoc clock hid omapdss sched_features usb bdi gpio mmc0 pm_debug tracing vram

in the gpio file, I have this:

GPIOs 160-191, gpio:
gpio-168 (sysfs ) out lo
gpio-170 (DVI_nPD ) out hi
gpio-171 (rev_id_0 ) in lo
gpio-172 (rev_id_1 ) in hi
gpio-173 (rev_id_2 ) in lo


So the gpio168 is right-configured here.

I don’t what is going wrong… Anyone can help?

Thanks in advance!

This is a pre-draft video about GPIO control on BeagleBoard : I hope it can help you. Regards, Jordi Al 16/04/12 11:38, En/na LPi ha escrit:

Thank you for this tutorial, but I’ve already done all the steps you are showing in your video.

Unfortunately, I guess that I have burnt my board today, and I don’t know why.

After doing the same manipulation as the video, I checked with a multimeter the voltage on the pin I just activated using GPIO, and the beagle crashed (no screen, and no serial).
Since this moment, I can’t access to the serial port, even after SDCard reformating… Otherwise, the leds next to the SDcard reader light up as the board as if loading the distrib. Maybe I damaged all the E/S from the beagle. In this cas, I will be in trouble with my mentor :frowning: (I’m doing a workplacement).

I don’t know what to do now, with a broken board where the chip is very warm.

Sounds like you may have shorted the pin to ground or one of the higher voltages. In this case most people get an RMA and have it looked at.


And there is no way to flash the firmware of the board via JTAG?

It depends on which BeagleBoard you have. The -xM has no flash. I have not heard of anyone using JTAG to write an SD card. The process for doing that is very easy and it seems to me to use JTAG just makes it more complicated.


Depending on the damage, it can be fixed and burned in and returned in 24 hours.