/*
   Demo of the simplest on/off button code for Tiny44
   Button connected to PA5 (physical pin 8 on tiny44)
   Red LED connected to PB2 (physical pin 5 of tiny44)
   
   For details on the use of the registers PORtx, DDRx, and PINx  (where x = A or B) see tutorials on AVR programming.

  This program was written by Robert Hart as a simple demonstration of programming AVR microcontrollers. 
	

*/

// ------- Preamble -------- //
#include <avr/io.h>

int main(void) {
  // -------- Inits --------- //
  PORTA = 0b00100000;  						/* initialize pullup resistor on our input pin by setting bit 5 of register PORTA high. */
  DDRB = 0b00000100;                        /* set up pin 2 of port B for output by setting bit 2 of register DDRB high.*/

  // ------ Event loop ------ //
  while (1) {
   	 										/* look for button press */
     if ((PINA & 0b00100000) == 0 ) { 		/* test to see if bit 5 of PINA is low  */
	  PORTB = 0b00000100;                   /* turn on LED on pin 3 of port B if bit is low (button is pressed) */
    }
    else {                                  /* otherwise */
      PORTB = 0b00000000;					/* leave output low.	*/
    }
   }										
    
                                        	 /* End event loop */
  return (0);	
 }