Greg, you nailed it! Currently I'm only using pins P8-7 through P8-12 via Python/Adafruit Lib, and sure enough they are the only pin bindings appearing in /sys/class/gpio; and when I "cat /sys/class/gpio<pin>/value" it actually returns the pin value without appearing to affect anything else.
Many thanks to you!!! On Friday, June 2, 2017 at 7:13:24 PM UTC-7, Greg wrote: > > POSIX type operating systems in general, including GNU/Linux, everything > is done by reading and/or writing to a file. > > The GPIO "files" are in the "virtual" file system located at > /sys/class/gpio. > > An example for header pin P9.14, which is GPIO 50: > > cat /sys/class/gpio/gpio50/value > > at the command line will return either 0 or 1, indicating the current > state. > Python and other languages have "system calls" which can do the same thing. > So you could create an array of the GPIOs you want to scan and loop > through them and determine their current state. > Different processes (programs) can read the values independent of one > another, so your "master" will be able to accomplish this. > > Regards, > Greg > -- 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]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/b3424806-be15-4d42-982b-8cb42e482644%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
