#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 clearpin(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


char SINE_LENGTH = 101;
char SINEWAVE[101] ={128,136,143,151,159,167,174,182,189,196,202,209,215,220,226,231,235,239,243,246,249,251,253,254,255,255,255,254,253,251,249,246,243,239,235,231,226,220,215,209,202,196,189,182,174,167,159,151,143,136,128,119,112,104,96,88,81,73,66,59,53,46,40,35,29,24,20,16,12,9,6,4,2,1,0,0,0,1,2,4,6,9,12,16,20,24,29,35,40,46,53,59,66,73,81,88,96,104,112,119,127};


#define MOSFET_PIN_A (1 << PA7)
#define MOSFET_PIN_B (1 << PB2) // output locations
#define TRIG_PIN (1<<PA3)
#define MOSFET_port PORTB

#define ARD_PA7 (7)
#define ARD_PB2 (8)
#define ARD_TRIG_PIN (3)

void setup(){}

void play_sine(int dSamps, int Cycs){ // frequency set by dSamps, number of cycles by Cycs
  for (int c = 0; c < Cycs; c++){
    for (int s = 0; s < SINE_LENGTH; s++){ // iterate over sine wave samples
      OCR0A = SINEWAVE[s];
      delayMicroseconds(dSamps);
    }
  }
}

void loop() {
  // put your setup code here, to run once:

  // set clock prescaler to to 1
  CLKPR = (1 << CLKPCE);
  CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
  
  // now, set WGM02:0 to 0x03 to enable fast PWM mode on OCR0B, OCR0A
  TCCR0B &= (~0x08); // clearing WGM02, and:
  TCCR0A |= 0x03; // setting WGM00, WGM01
  
  TCCR0B |= 0x01; TCCR0B &= (~0x06); //set clock divider to 1 for max speed

  // and set pin PA7 to output OCR0B output
  TCCR0A |= 0x20; // setting pin COM0B1 for non-inverting mode
  // TCCR0A |= 0x10; // un-commenting this line sets COM0B0 for inverting mode

  // and set pin PB2 to output OCR0A output
  TCCR0A |= 0x80; // setting pin COM0A1 for non-inverting mode
  // TCCR0A |= 0x40; // un-commenting this line sets COM0A0 to inverting mode

  // set data direction registers for proper I/O
  clearpin(PORTA, MOSFET_PIN_A); clearpin(PORTB, MOSFET_PIN_B);
  output(DDRA, MOSFET_PIN_A);
  output(DDRB, MOSFET_PIN_B);
  input(DDRA, TRIG_PIN);

  // put your main code here, to run repeatedly:
  while(1){
    if (pin_test(PINA,TRIG_PIN)) { // if PA3 is high


        // if pressed, begin chirp sequence. 
        // start with delay = 100 us (100 Hz), increment to 1000 us (10 Hz)
        for (int D = 1000; D>100; D=D-10){
          play_sine(D,1); //play 3 cycles at each freq
        }
    
       
         
    }
    else{ OCR0A = 0x00; OCR0B = 0x00;  }
  }
}