//
//
// hello.arduino.44.blink.button.c
//
// try to make an LED that blinks and interacts with a button
//
// original blink code Neil Gershenfeld
// 3/14/11
//
// (c) Massachusetts Institute of Technology 2011
// Permission granted for experimental and personal use;
// license for commercial sale available from MIT.
//
//Edits Perovich Oct 2012; change board to ATtiny44, change pins etc

#include <avr/io.h>
#include <util/delay.h>

#define output(directions,pin) (directions |= pin) // set port direction for output
#define set(port,pin) (port |= pin) // set port pin (turn on)
#define clear(port,pin) (port &= (~pin)) // clear port pin (turn off)
#define pin_test(pins,pin) (pins & pin) // test for port pin
#define bit_test(byte,bit) (byte & (1 << bit)) // test for bit set
#define led_delay() _delay_ms(300) // LED delay (changed from 100)

//LED defines: mine is port A (not B) for everything, because PA pin
#define led_port PORTA
#define led_direction DDRA
#define led_pin (1 << PA2)

//Button defines: mine is B (not A) for everything, because PB pin
#define button_port PORTB
#define button_pin (1 << PB2) 

int main(void) {
   //
   // main
   //
   // set clock divider to /1
   //
   CLKPR = (1 << CLKPCE);
   CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
   //
   // initialize LED pin
   //
   clear(led_port, led_pin);
   output(led_direction, led_pin);

	//Turn on pullup resistor on port B (so not floating)
	PORTB = _BV(PB2);

while(1) {
//PINB is port B input pins reading
//if evaluates to TRUE if nonzero
//If the button is not pressed, do nothing...
    if(pin_test(PINB, button_pin)){
        clear(led_port, led_pin);
    }
//If pin_test evaluates to false...
//If the button is pressed (and held down) blink the LED until it is released
    else{
        set(led_port, led_pin);
        led_delay();
        clear(led_port, led_pin);
        led_delay();
   }
}
}