GPIO burnout with Beaglebone black

I’m having a problem where GPIO pins will stop working the beaglebone black.

I’ve hooked up a 3.3v RS485 transceiver and that all seems to working fine. We hooked up a GPIO pin (pin 25 on P9, GPIO 117) to monitor the receive output of the transceiver to check to see if the bus is active or quiet.

This pin seems to work for a few minutes and the stop working forever on each beaglebone black. However, everything works just fine on our older beaglebone white boards. Any idea if something changed or what’s going on?

Are you doing this part correctly?

http://www.elinux.org/Beagleboard:BeagleBoneBlack#Expansion_Header_Usage

Gerald

To the best of my knowledge, yes. We’re using all kinds of pins and other parts of the board without issues.

You will want to check and see if the pin is being used is defaulted as an output, Some pins are outputs by default and others are inputs., If you start driving it before it is set to an input by SW, then that could cause issues. Check the datasheet for the AM3358.

Gerald

We’ve configured the pin as an input after the device boots. Even with with just a jumper wire between the two pins, an output and an input, the behavior on the black and white is different. Here’s how we set it up:

sudo sh -c ‘echo “60” > /sys/class/gpio/export’
sudo sh -c ‘echo “117” > /sys/class/gpio/export’
sudo sh -c ‘echo “in” > /sys/class/gpio/gpio60/direction’
sudo sh -c ‘echo “in” > /sys/class/gpio/gpio117/direction’
sudo sh -c ‘echo “falling” > /sys/class/gpio/gpio60/edge’
sudo sh -c ‘echo “falling” > /sys/class/gpio/gpio117/edge’

Did you compare the schematic of the two boards? There are two pins on the BBB that have a second optional pin connected to it. You need to make sure you take care of the one you are not using as well.

Gerald