Arduino Sleep & Wake up

아두이노 Wake up & Sleep 

#include <Wire.h>
#include <avr/sleep.h>

// I2C bus address declarations:
#define DS1337_I2C_ADDRESS 0x68  // DS1337

void wake ()
{
  // cancel sleep as a precaution
  sleep_disable();
  // must do this as the pin will probably stay low for a while
  detachInterrupt (0);
}

void setup() {
  // initialize ouptut pins
  pinMode(7, OUTPUT);

  // initialize I2C bus
  Wire.begin();

  // initialize RTC
  Wire.beginTransmission(DS1337_I2C_ADDRESS);  // Open I2C line in write mode
  Wire.write((byte)0x0E);                      // Set the register pointer
  Wire.write((byte)0x00);                      // Set the status register
  Wire.endTransmission();                      // End write mode
}

void loop() {
  digitalWrite(7, HIGH);
  digitalWrite(7, LOW);
  set_sleep_mode (SLEEP_MODE_PWR_DOWN);  
  sleep_enable();

  // Do not interrupt before we go to sleep, or the
  // ISR will detach interrupts and we won't wake.
  noInterrupts ();

  // will be called when pin D2 goes low  
  attachInterrupt (0, wake, LOW);

  interrupts();
  sleep_cpu();
}