AVR Freaks

Still i get wrong values: those are now bigger (57 instead of 50us)...

Bloody h*** there are wrong pulses in the beginning. And it prints those to 99% WTF...

#define NANOSECONDS_PER_TIC  500
#define MICROS_TO_TICS(mics)( mics * (unsigned long) 1000 / NANOSECONDS_PER_TIC)
#define TICS_TO_MICROS(tics)( tics * (unsigned long) NANOSECONDS_PER_TIC / 1000)

void setup(){

  Serial.begin(57600);
  delay(300);

  Serial.println(__DATE__);
  Serial.println(__TIME__);

  //all on pin 4 on ProMicro (ICP1)
  DDRB &= ~(1 << PB0);

  //testpin 6
  DDRD |= (1 << PD7);

  //testpin 2
  DDRD |= (1 << PD1);

  //testpin 3
  DDRD |= (1 << PD0);

  TCCR1A = 0;
  TCCR1B = 0;
  TIMSK1 = 0;
  TCCR1A = 0;

  //bit to one, raising edge!
  TCCR1B |= (1 << ICES1);

  //enable interrupt
  TIMSK1 |= (1 << ICIE1);

  //Timer overflow interrupt enable
  TIMSK1 |= (1 << TOIE1);

  TCCR1B |= (1 << CS11);  // full counter to FFFF / 8 prescaler, so 1 tic is 500ns
}

unsigned int lastICP = 0;
unsigned int currICP;
unsigned int pulseTics;

void loop(){
    cli();
    Serial.println(pulseTics);
    sei();
    delay(100);
}

/*
 * ca. 3us 10.01.2019
 * starts about 2us after edge change
 * ca. 10us 14.01.2019 0:36 (ohne delay(); welches zur Besseren Sichtbarkeit fürs oszi ist!)
 * ca. 8us 19.01.2019 21:51
 */
ISR(TIMER1_CAPT_vect){
 byte oldSREG = SREG;

  PORTD |= (1 << PD7);

  //get counter value
  currICP = ICR1;

  pulseTics = currICP - lastICP;

  lastICP = currICP;

  // toggle interrupt: next time with the other edge
  TCCR1B ^= (1 << ICES1);

  // if there was an uncaptured interrupt (a really short pulse < ~5us - there was only one interrupt for 2 edges), then edge select and current level will not correspond and there is no capture flag set.

  SREG = oldSREG;
  PORTD &= ~(1 << PD7);
}

ISR(TIMER1_OVF_vect){
  byte oldSREG = SREG;
  SREG = oldSREG;
}

Poor blind me... fixed those...

Still it gets almost only the bad pulses.

Well at least the values are correct now.

Thanks!

Of course did i implement your valuable suggestions!

It runs with 16Mhz.

This is the current program:

#define NANOSECONDS_PER_TIC  500
#define MICROS_TO_TICS(mics)( mics * (unsigned long) 1000 / NANOSECONDS_PER_TIC)
#define TICS_TO_MICROS(tics)( tics * (unsigned long) NANOSECONDS_PER_TIC / 1000)


void setup(){

  Serial.begin(57600);
  delay(300);

  Serial.println(__DATE__);
  Serial.println(__TIME__);

  //all on pin 4 on ProMicro (ICP1)
  DDRB &= ~(1 << PB0);

  //testpin 6
  DDRD |= (1 << PD7);

  //testpin 2
  DDRD |= (1 << PD1);

  //testpin 3
  DDRD |= (1 << PD0);


  TCCR1A = 0;
  TCCR1B = 0;
  TIMSK1 = 0;
  TCCR1A = 0;

  //bit to one, raising edge!
  TCCR1B |= (1 << ICES1);

  //enable interrupt
  TIMSK1 |= (1 << ICIE1);

  //Timer overflow interrupt enable
  TIMSK1 |= (1 << TOIE1);

  TCCR1B |= (1 << CS11);  // full counter to FFFF / 8 prescaler, so 1 tic is 500ns
}


unsigned int lastICP = 0;
unsigned int currICP;
volatile unsigned int pulseTics;

void loop(){
    unsigned int pulseCopy;
    cli();
    pulseCopy = pulseTics;
    sei();
    Serial.println(TICS_TO_MICROS(pulseCopy));
    delay(100);
}


/*
 * ca. 3us 10.01.2019
 * starts about 2us after edge change
 * ca. 10us 14.01.2019 0:36 (ohne delay(); welches zur Besseren Sichtbarkeit fürs oszi ist!)
 * ca. 8us 19.01.2019 21:51
 */
ISR(TIMER1_CAPT_vect){
 byte oldSREG = SREG;

  PORTD |= (1 << PD7);
  
  //get counter value
  currICP = ICR1;

  pulseTics = currICP - lastICP;
  
  lastICP = currICP;

  // toggle interrupt: next time with the other edge
  TCCR1B ^= (1 << ICES1);

  // if there was an uncaptured interrupt (a really short pulse < ~5us - there was only one interrupt for 2 edges), then edge select and current level will not correspond and there is no capture flag set.
 
  SREG = oldSREG;
  PORTD &= ~(1 << PD7);
}


ISR(TIMER1_OVF_vect){
  byte oldSREG = SREG;
  SREG = oldSREG;
}