I'm trying and failing to read a digital IO pin on the beaglebone.
I can write to it fine using these commands:
echo 7 >/sys/kernel/debug/omap_mux/gpmc_ad0
echo 32 >/sys/class/gpio/export
echo high >/sys/class/gpio/gpio32/direction
Using low instead of high switches from 3.3V to 0V and back
as expected.
However, subsequent commands like this:
echo in >/sys/class/gpio/gpio32/direction
cat /sys/class/gpio/gpio32/direction/value
Always print 0, regardless of whether its hooked to 3.3V or not.
Interestingly, the output of
cat /sys/kernel/debug/omap_mux/board/core
changes after 'echo high ...' to indicate that the pin is configured
as an output, but never changes back. But even if I check
/sys/class/gpio/gpio32/value before ever writing to direction,
it doesn't reflect the actual voltage on the pin.
I'm wondering if there is something I'm missing in the way the /sys
interface is supposed to work.
Any help or advice greatly appreciated,
Britton
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