#How to read the Arietta on-board button

The P1 push button mounted on Arietta G25 is wired between the PC17 GPIO
line of the Atmel CPU and the ground as visible on the [Arietta G25 schematic](/schematics/schematic_arietta.pdf).

Like any other GPIOs it is possible to read its value using the sysfs 
user interface.

The Kernel ID to use to select this GPIO is __81__.

Export the GPIO line 81 by typing:

<pre class="minicom">
# echo "81" > /sys/class/gpio/export
</pre>

Read the actual button state:

<pre class="minicom">
# cat /sys/class/gpio/pioC17/value
1
</pre>

Now try to press the button and type again: 

<pre class="minicom">
# cat /sys/class/gpio/pioC17/value
0
</pre>