//Pins
const int led_pin = PB5;//D13-->PB5

//Counter and compare values
const uint16_t t1_load = 0;
const uint16_t t1_comp =31250;// timer clk:16Mhz, 1ms duration (16MHz)(1ms) 16,000
//ADC Variables
volatile bool flgAcqDone = false;
const int bLen =20; //128;
volatile int buffer[bLen + 1];

void setup() {
  Serial.begin(9600);
  cli();
  //----------Counter timer setup
  //Set LED Pin to be output
  //PORTB=b00000000;
  //DDRB=b00000000; //D13-->PB5
  DDRB |= (1 << led_pin);
  //Serial.print("DDRB: "); Serial.println(DDRB, BIN);
  newsetup();
  /*
    //Reset Timer1 Control Register
    //Timer Counter Control Reg 1A TCCR1A
    //b7       b6       b5       b4       b3       b2       b1     b0
    //COM1A1   COM1A0   COM1B1   COM1B0   -        -        WGM11  WGM10

    TCCR1B = 0;
    TCCR1A = 0;

    //Reset Timer1 and set compare value
    //Timer Counter Control Reg 1B  TCCR1B
    //b7       b6       b5       b4       b3       b2       b1     b0
    //ICNC1    ICES1    -        WGM13    WGM12    CS12     CS11   CS10
    //Set prescaler to 256: b2 b1 b0= 100 XXX set prescaler X1=16MHz CS12, CS11, CS10=001
    TCCR1B |= (1 << CS12);
    TCCR1B &= ~(1 << CS11);
    TCCR1B &=  ~(1 << CS10);

    //Set CTC Mode (Clear Timer on Compare Match)
    TCCR1B &= ~(1 << WGM13);
    TCCR1B |=  (1 << WGM12);
    Serial.print("TCCR1B: "); Serial.println(TCCR1B, BIN);

    //Reset Timer1 and set compare values
    //Timer Counter 1: TCNT1H TCNT1L 2 bytes = TCNT1
    //Timer Counter 1 Output Compare Register B High & Low byte OCR1B=OCR1BH,OCR1BL
    TCNT1 = t1_load;
    OCR1B = t1_comp;
    OCR1A = t1_comp;//Seems had to int to make work
    Serial.print("OCR1B: "); Serial.println(OCR1B, HEX);
    Serial.print("TCNT1: "); Serial.println(TCNT1, BIN);



    //Enable Timer1 compare interrupt
    //Timer/counter1 Interrupt Mask Register
    //b7       b6       b5       b4       b3       b2       b1     b0
    //-         -       ICIE1    -        -        OCIE1B   OCIE1A TOIE1
    TIMSK1 = (1 << OCIE1B);
    Serial.print("TIMSK1: "); Serial.println(TIMSK1, BIN);


    //------------ADC Setup--------------------------
    //ADSRA ADC Control anb Status Register
    //b7       b6       b5       b4       b3       b2       b1     b0
    //ADEN     ADSC     ADATE    ADIF     ADIE     ADPS2    ADPS1  ADPS0

    //ADMUX ADC Multplexer Selection Regester
    //b7       b6       b5       b4       b3       b2       b1     b0
    //REFS1    REFS0    ADLAR    -        MUX3     MUX2     MUX1   MUX0
    ADCSRA |= B00000111;//1<<ADPS2 |= 1<<ADPS1 |= 1<<ADPS0;//Set Prescaler to 128 Fclk,ADC=16MHz/128=125kHz <200kHz
    ADMUX &= 0 << ADLAR; //Sets 10 bit result
    ADMUX |= 1 << REFS0; //Select adc reference (AVCC with external cap at AREF pin)

    //ADCSRB
    //b7       b6       b5       b4       b3       b2       b1       b0
    //-        ACME     -         -       -        ADTS2    ADTS1    ADTS0
    //Set ADC Trigger Timer/Counter1 compare match B ADTS2, ADTS1, ADTS0= 101
    ADCSRB |=  (1 << ADTS2);
    ADCSRB &= ~(1 << ADTS1);
    ADCSRB |=  (1 << ADTS0);
    Serial.print("ADCSRB: "); Serial.println(ADCSRB);

    //ADCSRA
    //b7       b6       b5       b4       b3       b2       b1       b0
    //ADEN     ADSC     ADATE    ADIF     ADIE     ADPS2    ADPS1    ADPS0
    ADCSRA |= 1 << ADIE; //Enable interrupts
    ADCSRA |= 1 << ADEN; //Enable ADC
    ADCSRA |= 1 << ADATE; //1: Enables Auto Trigging
    ADCSRA &= ~(1 << ADSC); //aLLow Timer1 to trigger start conversion
    ADCSRA |= 1 << ADIF; //1: AD Interrupt Flag
    sei();//Enable global interrupts

    // ADCSRA |= 1 << ADSC; //Start first conversion

    Serial.print("ADCSRA: "); Serial.println(ADCSRA);
    //Enable Global interrupts
    // Serial.print("SREG: "); Serial.println(SREG);
  */

  sei();
  ADCSRA |= 1 << ADSC; //Start first conversion
  //Serial.print("SREG: "); Serial.println(SREG);
}

void newsetup() {
  //https://forum.arduino.cc/t/help-with-adc-auto-triggering/215511/4
  const uint16_t smpl_Time = 4096;
  //ADCSRA
  //b7       b6       b5       b4       b3       b2       b1       b0
  //ADEN     ADSC     ADATE    ADIF     ADIE     ADPS2    ADPS1    ADPS0
  ADCSRA = (1 << ADEN) |	// 1 = ADC Enable
           (0 << ADSC) &	// ADC Start Conversion
           ~(1 << ADATE) |	// 1 = ADC Auto Trigger Enable
           (0 << ADIF) |	// ADC Interrupt Flag
           (0 << ADIE) |	// ADC Interrupt Enable
           (1 << ADPS2) |
           (1 << ADPS1) |	// ADC Prescaler : ADS0=0 Selects 250 kHz. // ADS0=1 Selects 125 kHz.
           (1 << ADPS0);

  //ADCSRB
  //b7       b6       b5       b4       b3       b2       b1       b0
  //-        ACME     -         -       -        ADTS2    ADTS1    ADTS0
 // ADCSRB = ((1 << ADTS2) | // Sets Auto Trigger source - Timer/Counter1 Compare Match B
 //           (0 << ADTS1) |
 //           (1 << ADTS0));
ADCSRB = ((0 << ADTS2) & (0 << ADTS1) & (0 << ADTS0)); // Sets Freerun mode
            
  /* Set up TIMER 1 - ADC sampler */
  TIMSK0 = 0x00;
  TIMSK1 = 0x00;
  TIMSK2 = 0x00;

  TCCR1A = 0;
  TCCR1B = 0;
  TCCR1C = 0;

  TCCR1A =  ((1 << WGM11) | (1 << WGM10));   // Mode 15, Fast PWM
  TCCR1B =  ((1 << WGM13) | (1 << WGM12));   // Mode 15, Fast PWM

  TCCR1B |= (1 << CS12) | (1 << CS10); // (1 << CS10);                    // clk/1 prescaling.
  //TCCR1B &= ~((1<<CS12) | (1<<CS10));
  OCR1A  = smpl_Time;
  OCR1B  = smpl_Time;

  TCNT1  = 0;
  TIFR1   |= (1 << OCF1B);
  TIMSK1  |= (1 << OCIE1B);
}

void loop() {
       delay(500);//Fake do something
 
  //Serial.print("flgAcqDone: "); Serial.println(flgAcqDone);
  if (flgAcqDone == true) {
    for (int j = 0; j < bLen; j++) {
     // Serial.print("Buffer["); Serial.print(j); Serial.print("]= ");
      Serial.println(buffer[j]);
    }//for
    flgAcqDone = false;
  }//if

}

ISR(TIMER1_COMPB_vect) {
 // Serial.println("ISR(TIMER1_COMPB_vect)");
  static int i = 0;
  PORTB ^= (1 << led_pin);//Toggle D13 bit located in PORTB
  ADCSRA |= 1 << ADSC; //Start conversion
  flgAcqDone = false;
  while (bitRead(ADCSRA, ADSC) == 1) {
    //Serial.println("wait");
  }
  buffer[i] = ADCL | (ADCH << 8);
  //Serial.println(buffer[i]);
  i++;
   if (i == bLen) {
    i = 0;
    flgAcqDone = true;
  }
  //Serial.print("ADCSRA: "); Serial.println(ADCSRA,HEX);
  //Serial.print("1<<ADIF: "); Serial.println(1 << ADIF, HEX);
  //Serial.print("(1<<ADIF)&ADCSRA=: "); Serial.println((1 << ADIF)&ADCSRA, HEX);
  // Serial.print("bitRead(ADCSRA,ADIF)"); Serial.println(bitRead(ADCSRA,ADIF), HEX);
  // Serial.print("Buffer["); Serial.print(i); Serial.print("]= ");
  // Serial.println(buffer[i]);


 
}

/*
ISR(ADC_vect)
{
  Serial.println("ISR(ADC_vect)");
  flgAcqDone = false;
  static int i = 0;

  buffer[i] = ADCL | (ADCH << 8);
  Serial.print("Buffer["); Serial.print(i); Serial.print("]= ");
  Serial.println(buffer[i]);
  i++;
  if (i == bLen - 1) {
    i = 0;
    flgAcqDone = true;
  }
  //ADCSRA |= 1 << ADSC; //Start Next conversion
  ADCSRA &= 0 << ADSC; //Clear
}
*/

/*
  //https://arduino.stackexchange.com/questions/58224/running-adc-triggered-by-timer1-compb
  #define SAMPLES_SIZE  205

  const int adc_channel = 0;
  const uint16_t t1_load = 0;

  // 250 corresponds to 8kHz
  const uint16_t t1_comp = 25000;

  uint16_t samples[SAMPLES_SIZE];
  volatile uint8_t samplePos = 0;

  static int x = 0;

  void initADC() {
  // Init ADC free-run mode; f = ( 16MHz/prescaler ) / 13 cycles/conversion
  ADMUX  = adc_channel; // Channel sel, right-adj, use AREF pin
  ADCSRA = _BV(ADEN)  | // ADC enable
           _BV(ADSC)  | // ADC start
           _BV(ADATE) | // Auto trigger
           _BV(ADIE)  | // Interrupt enable
           _BV(ADPS2) | _BV(ADPS1) | _BV(ADPS0); // 128:1 / 13 = 9615 Hz
  ADCSRB = _BV(ADTS2) | _BV(ADTS0);              // Timer/Counter1 Compare Match B
  DIDR0  = _BV(adc_channel); // Turn off digital input for ADC pin
  }

  void initTimer() {
  // Reset Timer1 Control Reg A
  TCCR1A = 0;

  // Set CTC mode
  TCCR1B &= ~(1 << WGM13);
  TCCR1B |= (1 << WGM12);

  // Set prescaler to 8
  TCCR1B &= ~(1 << CS12);
  TCCR1B |= (1 << CS11);
  TCCR1B &= ~(1 << CS10);

  // Reset Timer 1 and set compare value
  TCNT1 = t1_load;
  OCR1B = t1_comp;

  // Enable Timer 1 compare interrupt
  TIMSK1 = (1 << OCIE1B);
  }

  void setup() {
  cli();
  initADC();
  initTimer();
  sei();

  Serial.begin(115200);
  }

  void loop() {
  while(ADCSRA & _BV(ADIE)); // Wait for audio sampling to finish
  cli();

  // x = x + 2;
  // Serial.print(samples[0]);
  //  Serial.print("\t");
  // Serial.println(x);



  for (int i = 0; i < SAMPLES_SIZE; i++) {
    Serial.println(samples[i]);
  }
  samplePos = 0;


  ADCSRA |= _BV(ADIE);       // Resume sampling interrupt
  sei();
  }

  ISR(ADC_vect) {
  Serial.println("ISR(ADC_vect)");
  int16_t sample = ADC;

  samples[samplePos] = sample;
  samplePos++;
  ADCSRA &= ~_BV(ADIE); // Buffer full, interrupt off

  if(samplePos >= SAMPLES_SIZE) {
    ADCSRA &= ~_BV(ADIE); // Buffer full, interrupt off
  }
  }

  ISR(TIMER1_COMPB_vect) {
  Serial.println("ISR(ADC_vect)");
  TCNT1 = 0;
  }
*/