Arduino Yún Linux Programming - The Hands-on Arduino Yun Manual Lab - page 86

4.5 Bridge Library and Python
It is not possible to access the I/O pins of the Atheros AR9331. All I/O lines are tied to the
32U4. Arduino Yún provides a bridge which connect between Arduino and Linux OpenWrt.
The following is a bridge architecture.
(source: http://arduino.cc/en/Guide/ArduinoYun)
In this section, we try to use Yun Bridge Library, http://arduino.cc/en/Reference/Yun-
BridgeLibrary , to communicate between Arduino and Linux (Linino).
Firstly, we open Arduino Sketch and write this code.
#include <Bridge.h>
unsignedlong counter;
void setup ()
{
counter = 0 ;