On 1/12/2014 3:57 PM, Charles Steinkuehler wrote: > On 1/12/2014 2:44 PM, Thomas Studwell wrote: >> Charles, I didn't see any reference to 'high' being a valid 'direction' >> using the virtual GPIO pins, so I added these to the end of the setup.sh >> file. If I get time later today or tomorrow, I'll update the script to >> process an optional 'level' parameter to the pin list rather than >> hardcoding it like this. >> >> Included text: >> sudo -A su -c "echo 1> /sys/class/gpio/gpio44/value" >> sudo -A su -c "echo 1> /sys/class/gpio/gpio46/value" >> sudo -A su -c "echo 1> /sys/class/gpio/gpio48/value" > Making me provide references, eh? Well, OK: > > https://www.kernel.org/doc/Documentation/gpio/gpio-legacy.txt > > ...scroll down to "Paths in Sysfs" where you will find: > > /sys/class/gpio/gpioN/ > > "direction" ... reads as either "in" or "out". This value may > normally be written. Writing as "out" defaults to > initializing the value as low. To ensure glitch free > operation, values "low" and "high" may be written to > configure the GPIO as an output with that initial value. > > Note that this attribute *will not exist* if the kernel > doesn't support changing the direction of a GPIO, or > it was exported by kernel code that didn't explicitly > allow userspace to reconfigure this GPIO's direction. > My bad. Thank you for the reference AND the gentle reminder that the GPIO world doesn't revolve around BBB documentation :-)
Tom ------------------------------------------------------------------------------ CenturyLink Cloud: The Leader in Enterprise Cloud Services. Learn Why More Businesses Are Choosing CenturyLink Cloud For Critical Workloads, Development Environments & Everything In Between. Get a Quote or Start a Free Trial Today. http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
