ATiny85 Sleep Example.cpp

/*
 * ATTINY85 Sleep Example
 * by kevinwatts
 *
 * Commenting added by Dustin Westaby
 */

#include <avr/sleep.h>
#inlcude <avr/io.h>

//clear bit macro
#ifndef cbi
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif

//set bit macro
#ifndef sbi
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif

const int led_pin = 0;
const int interrupt_pin1 = 1;
const int interrupt_pin2 = 2;
int which_pin = 1;

void setup(){

//Set all pins to inputs w/ pull-up resistors (stop them from floating or sourcing power)
for (byte i=0; i<5; i++) {     
    pinMode(i, INPUT);
    digitalWrite(i, HIGH);
	}
	
//set LED pin to output
pinMode(led_pin,OUTPUT);

//Blink so I know you've reset/started
for (byte i=0; i<3; i++) {     
    digitalWrite(led_pin, HIGH);
    delay(500);
    digitalWrite(led_pin, LOW);
    delay(500);
	}
  
  sbi(GIMSK,PCIE); // Turn on Pin Change interrupts (Tell Attiny85 we want to use pin change interrupts (can be any pin))
  sbi(PCMSK,PCINT1); //Define which pins are doing the interrupting (digital pin 1, DIP 7 in this example)
  sbi(PCMSK,PCINT2); //Define which pins are doing the interrupting (digital pin 2, DIP 6 in this example)
}

void loop(){
	for(byte i=0; i<whichpin; i++){   //Blink to let me know which interrupt was pressed
		digitalWrite(led_pin,HIGH);
		delay(500);
		digitalWrite(led_pin,LOW);
		delay(500);
	}

  hush_lil_uC();   //Call the sleep function
}

// From http://interface.khm.de/index.php/lab/experiments/sleep_watchdog_battery/
void hush_lil_uC(); {
  cbi(ADCSRA,ADEN); //Switch Analog to Digital converter OFF
  set_sleep_mode(SLEEP_MODE_PWR_DOWN); // Set sleep mode
  sleep_mode(); //Go to sleep
  sbi(ADCSRA,ADEN);//Switch Analog to Digital converter back ON
}

ISR(PCINT0_vect) {     //All interrupts direct to this ISR function
	if(digitalRead(interrupt_pin1)==LOW){
		which_pin = 3;
	}
	else if(digitalRead(interrupt_pin2)==LOW){
		which_pin = 6;
	}
	else{
		which_pin = 1;
	}
}