//
// hello.servo.44.c
//
// servo motor hello-world
//
// set lfuse to 0x7E for 20 MHz xtal
//
// Neil Gershenfeld---modification by Jose Figueroa 19/03/2013
// 4/8/12
//
// (c) Massachusetts Institute of Technology 2012
// Permission granted for experimental and personal use;
// license for commercial sale available from MIT.
//

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

#define output(directions,pin) (directions |= pin) // set port direction for output
#define input(directions,pin) (directions &= (~pin)) // set port direction for input
#define set(port,pin) (port |= pin) // set port pin
#define clear(port,pin) (port &= (~pin)) // clear port pin
#define pin_test(pins,pin) (pins & pin) // test for port pin
#define bit_test(byte,bit) (byte & (1 << bit)) // test for bit set
#define position_delay() _delay_ms(1000)

#define PWM_port PORTB
#define PWM_pin (1 << PB2)
#define PWM_direction DDRB
#define input_port PORTA
#define input_direction DDRA
#define input_pin (1 << PA3)
#define input_pins PINA

int main(void) {
   //
   // main
   //
   // set clock divider to /1
   //
   CLKPR = (1 << CLKPCE);
   CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
   //
   // set up timer 0
   //
   TCCR0A = (1 << COM0A1) | (0 << COM0A0) | (0 << WGM01) | (1 << WGM00); // clear OC0A on compare match
   TCCR0B = (0 << CS02) | (1 << CS01) | (0 << CS00) | (0 << WGM02); // prescaler /8, phase and frequency correct PWM, 0xFF TOP

   //
   // set PWM pin to output
   //
   clear(PWM_port, PWM_pin);
   output(PWM_direction, PWM_pin);
   set(input_port, input_pin); // turn on pull-up
   input(input_direction, input_pin);
   //
   // main loop
   //
   while (1) {

	   while (0 == pin_test(input_pins,input_pin))
	            ;

      OCR0A = 50;
      position_delay();

      OCR0A = 250;
      position_delay();
      }
   }