====== Controlling GPIO's ======
===== About =====

This short tutorial describes how to get GPIO working. For this you need tool called ''gpioctl''.

===== Building/installing =====

  * Type ''make menucongfig''
  * Under ''Utilities'' select package ''gpioctl'' and build carambola firmware (although you can do it directly on carambola typing ''opkg update; opkg install gpioctl'')
  * In latest OpenWrt revisions gpioctl become deprecated.

===== Testing =====
==== Prepare GPIO as output ====

  gpioctl dirout 1;  gpioctl dirout 2

==== Set both to 1 ====

  gpioctl set 1; gpioctl set 2

==== Clear both ====

  gpioctl clear 1; gpioctl clear 2

==== Read status ====

  gpioctl dirin 1; gpioctl dirin 2; gpioctl get 1; gpioctl get 2
  
===== Controlling gpio pins as files in /sys =====
Another method for controlling gpios using files instead of commands:
  cd /sys/class/gpio
  echo 1 > export 
this will make the virtual directory "gpio1" available in /sys/class/gpio/gpio1
inside "gpio1" you will find, among others:
  * direction ("in" or "out")
  * value (0 or 1)
Just write/read those file to do I/O.
For example 
  echo out > direction
  echo 1 > value
will put the pin in output mode and high
  echo in > direction
  cat value
will read the pin instead