#include <avr/sleep.h>    // Sleep Modes
#include <avr/power.h>    // Power management

// ATMEL ATTINY 25/45/85 / ARDUINO
// Pin 1 is /RESET
//
//                  +-\/-+
// Ain0 (D 5) PB5  1|    |8  Vcc
// Ain3 (D 3) PB3  2|    |7  PB2 (D 2) Ain1 
// Ain2 (D 4) PB4  3|    |6  PB1 (D 1) pwm1
//            GND  4|    |5  PB0 (D 0) pwm0
//                  +----+

#define blink_delay 250
#define led_pin 0

int loop_cnt = 0;

void setup() {
  // put your setup code here, to run once:
  // Debug.begin();
  // Debug.println("setting up");  
  //adc_disable(); // ADC uses ~320uA
  //set_sleep_mode(SLEEP_MODE_PWR_DOWN); 
  blink_it(1);
}

void loop() {

  loop_cnt++;
  // put your main code here, to run repeatedly:
  // Debug.print("starting loop ");   
  // Debug.println(loop_cnt);
  blink_it(2);
  delay(100);
  goToSleep();
  // Sleep();
  blink_it(3);
  // Debug.print("ending loop ");   
  // Debug.println(loop_cnt);
  delay(2000);
}

// --------------------------------------- FUNCTIONS
void goToSleep ()
  {
  set_sleep_mode (SLEEP_MODE_PWR_DOWN);
  noInterrupts ();       // timed sequence coming up
  
  sleep_enable ();       // ready to sleep
  interrupts ();         // interrupts are required now
  // Debug.println("about to sleep");
  sleep_cpu ();          // sleep                
  sleep_disable ();      // precaution
  }  // end of goToSleep 

void Sleep() {

    GIMSK |= _BV(PCIE);                     // Enable Pin Change Interrupts
    PCMSK |= _BV(PCINT3);                   // Use PB3 as interrupt pin
    ADCSRA &= ~_BV(ADEN);                   // ADC off
    set_sleep_mode(SLEEP_MODE_PWR_DOWN);    // replaces above statement

    sleep_enable();                         // Sets the Sleep Enable bit in the MCUCR Register (SE BIT)
    sei();                                  // Enable interrupts
    sleep_cpu();                            // sleep

    cli();                                  // Disable interrupts
    PCMSK &= ~_BV(PCINT3);                  // Turn off PB3 as interrupt pin
    sleep_disable();                        // Clear SE bit
    ADCSRA |= _BV(ADEN);                    // ADC on

    sei();                                  // Enable interrupts
} // sleep

ISR(PCINT0_vect) {
    // This is called when the interrupt occurs, but I don't need to do anything in it
}

void blink_it(int times) {
  int i;
  for (i=1; i <= times; i++) {
    digitalWrite(led_pin, HIGH);
    delay(blink_delay);
    digitalWrite(led_pin, LOW);
    delay(blink_delay);
  }  
  delay(2000);
}