mianqi2016

#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/atomic.h>
#include <util/delay.h>
#include <stdbool.h>

/*
 * A global flag used to communicate between the Interrupt Service Routine
 * and the main program.  It has to be declared volatile or the compiler
 *  might optimize it out.