I am trying to change the pin mode on my BBB, following the instructions on Derek Molloy’s tutorial video (https://www.youtube.com/watch?v=wui_wU1AeQcf, related text article here: http://derekmolloy.ie/gpios-on-the-beaglebone-black-using-device-tree-overlays/) and scripts. I have followed his directions exactly, only replacing the offests and modes in the .dts file with my own specifications. I compiled using ./build, copied the .dtbo file to /lib/firmware, and used echo DM_GPIO_Test > $SLOTS to apply the overlay. I didn’t get any errors throughout the entire process.
When I run cat $SLOTS to see if it has applied, it shows the following, indicating that the overlay was applied:
root@beaglebone:~/Desktop/boneDeviceTree/overlay# cat $SLOTS
4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G
5: ff:P-O-L Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI
7: ff:P-O-L Override Board Name,00A0,Override Manuf,DM-GPIO-Test
All seems well, so I go export the GPIO pins I need and go to test them (I have a decent amount of experience testing GPIO in Linux, but not on the BBB), but run into a whole bunch of unexpected behavior (some pins not registering inputs, not being pulled up/down as expected, etc). So I try cat $PINS | grep on a few of the pins I’ve changed, and see that they still have the default values (and the defaults line up with the GPIO test results in terms of being pulled up/down or not being in GPIO mode at all).
I went back and re-watched the video and can’t see any problems, up until after the echo DM_GPIO_Test > $SLOTS part, where he runs dmesg, and I see that apparently nothing happened on my board at all. None of the “bone-capemgr bone_capemgr.9: slot #6: [stuff]” shows up.
So, that’s where I’m stuck. I would very much appreciate any help, and please let me know if you have any more questions, I’m not really sure what might be the problem here.
Possibly pertinent info:
uname -a returns this: Linux beaglebone 3.8.13 #1 SMP Wed Sep 4 09:09:32 CEST 2013 armv7l GNU/Linux (date and time incorrect)
I am using Angstrom.
No capes are installed.