/*
 * Sam Guzauskas
 * Adapted From:
 * 
 * Liz Schell
 */ 

#define F_CPU 20000000    // AVR clock frequency in Hz, used by util/delay.h
#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 led_delay(ms) _delay_ms(ms) // LED delay
#define PWM_delay() _delay_us(25) // PWM delay

#define red_port PORTA
#define green_port PORTA
#define blue_port PORTA
#define led_direction DDRA
#define red_led (1 << PA2)
#define green_led (1 << PA3)
#define blue_led (1 << PA7)

#define input_port PORTB
#define input_direction DDRB
#define input_pins PINB
#define input_pin (1 << PB2)

int main(void) {
//
// main
//
unsigned char count, pwm;
//
// set clock divider to /1
//
CLKPR = (1 << CLKPCE);
CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
//
// initialize LED pins
//
set(red_port, red_led);
output(DDRA, red_led);
set(green_port, green_led);
output(DDRA, green_led);
set(blue_port, blue_led);
output(DDRA, blue_led);
set(input_port, input_pin);
input(input_direction, input_pin);

int sequence = 0;

while(1){
   while (0 != pin_test(input_pins, input_pin)){
       _delay_ms(2);
   }

   while (0 == pin_test(input_pins, input_pin)){
        sequence = 1;
   }

   while (sequence){
       //
       // off -> red
       //
      for (count = 0; count < 255; ++count) {
         set(red_port,red_led);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         clear(red_port,red_led);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }
      //
      // red -> green
      //
      for (count = 0; count < 255; ++count) {
         clear(red_port,red_led);
         set(green_port,green_led);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         set(red_port,red_led);
         clear(green_port,green_led);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }
      //
      // green -> blue
      //
      for (count = 0; count < 255; ++count) {
         clear(green_port,green_led);
         set(blue_port,blue_led);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         set(green_port,green_led);
         clear(blue_port,blue_led);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }
      //
      // blue -> on
      //
      for (count = 0; count < 255; ++count) {
         clear(blue_port,blue_led);
         set(green_port,green_led);
         set(red_port,red_led);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         clear(blue_port,blue_led);
         clear(green_port,green_led);
         clear(red_port,red_led);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }

      //
      // on -> off
      //
      for (count = 0; count < 255; ++count) {
         clear(blue_port,blue_led);
         clear(green_port,green_led);
         clear(red_port,red_led);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         set(blue_port,blue_led);
         set(green_port,green_led);
         set(red_port,red_led);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }
      sequence = 0;
      }
    }
   }