I've been trying to get input and output GPIOs to work following Derek Molloy's videos and book. I'm using Debian 7/3.8.13-bone68. Pin 36, by default, is configured as an input with pullup enabled. When I measure that pin with a DMM, it's near 3.3 V. But when I try to read the value via sysfs, I always get 0.
Here's how things look for pin 36, P8_07: # cat /sys/kernel/debug/pinctrl/44e10800.pinmux/pins | grep 890 pin 36 (44e10890) 00000037 pinctrl-single # ls /sys/class/gpio export gpio36 gpiochip0 gpiochip32 gpiochip64 gpiochip96 unexport # cat /sys/class/gpio/gpio36/direction in # cat /sys/class/gpio/gpio36/value 0 # cat /sys/devices/bone_capemgr.9/slots 0: 54:PF--- 1: 55:PF--- 2: 56:PF--- 3: 57:PF--- 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 Similarly I tried setting the direction to "out", and tried setting the value, but it had no effect on the output voltage. Am I missing a step? I followed the instructions here: http://derekmolloy.ie/gpios-on-the-beaglebone-black-using-device-tree-overlays/ I also tried setting up the overlay as directed later in the example, but it made no difference. I'd really appreciate any help! -- Rick Mann [email protected] -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
