Okay, I installed the 2014-12-11 bone-console test image onto an SD card, booted from that, and tried again, with the same result. I guess I should go back to the version used by Derek Molloy.
> On Dec 25, 2014, at 03:26 , Rick Mann <[email protected]> wrote: > > 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. -- 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.
