How to sync PWM signal using zero crossing detection

Projects Programming
1

I am trying to sync my sine PWM (50Hz) to a zero cross detector signal. So basically I want my PWM generation to restart once I got the signal from the ZCD, right? I can not seem to manage that (I tried more than just setting TCNT1 = 0). The frequency of the PWM is almost correct so it just keeps shifting very slowly.

You can see on the attached photos the PWM signal (of one pin), the signal on which to lock onto and the ZCD signal.

But I am not great with Arduino code and especially with using the timers and PWM coding.

int i=0;
int x=0;
int OK=0;
int val = 0;
int test = 0;
int analogPin = 2; 
int sinPWM[]={1,2,5,7,10,12,15,17,19,22,24,27,30,32,34,37,39,42,
44,47,49,52,54,57,59,61,64,66,69,71,73,76,78,80,83,85,88,90,92,94,97,99,
101,103,106,108,110,113,115,117,119,121,124,126,128,130,132,134,136,138,140,142,144,146,
148,150,152,154,156,158,160,162,164,166,168,169,171,173,175,177,178,180,182,184,185,187,188,190,192,193,
195,196,198,199,201,202,204,205,207,208,209,211,212,213,215,216,217,219,220,221,222,223,224,225,226,227,
228,229,230,231,232,233,234,235,236,237,237,238,239,240,240,241,242,242,243,243,244,244,245,245,246,246,
247,247,247,248,248,248,248,249,249,249,249,249,255,255,255,255,249,249,249,249,249,248,
248,248,248,247,247,247,246,246,245,245,244,244,243,243,242,242,241,240,240,239,238,237,237,236,235,234,
233,232,231,230,229,228,227,226,225,224,223,222,221,220,219,217,216,215,213,212,211,209,208,207,205,204,
202,201,199,198,196,195,193,192,190,188,187,185,184,182,180,178,177,175,173,171,169,168,166,164,162,160,
158,156,154,152,150,148,146,144,142,140,138,136,134,132,130,128,126,124,121,119,117,115,113,110,108,106,
103,101,99,97,94,92,90,88,85,83,80,78,76,73,71,69,66,64,61,59,57,54,52,49,47,44,42,39,37,34,32,30,
27,24,22,19,17,15,12,10,7,5,2,1};

void setup() {
Serial.begin(9600);

pinMode(5, OUTPUT);
pinMode(6,OUTPUT);
pinMode(2,INPUT);

cli();// stop interrupts
TCCR0A=0;//reset the value
TCCR0B=0;//reset the value
TCNT0=0;//reset the value
//0b allow me to write bits in binary
TCCR0A=0b10100001;//phase correct pwm mode
TCCR0B=0b00000001; //no prescaler
TCCR1A=0;//reset the value
TCCR1B=0;//reset the value
TCNT1=0;//reset the value
OCR1A=507;// compare match value
TCCR1B=0b00001001; //WGM12 bit is 1 and no prescaler

TIMSK1 |=(1 << OCIE1A);

sei();// enable interrupts
}
ISR(TIMER1_COMPA_vect){// interrupt when timer 1 match with OCR1A value
if(i>313 && OK==0){// final value from vector for pin 6
i=0;// go to first value of vector
OK=1;//enable pin 5
}
if(i>313 && OK==1){// final value from vector for pin 5
i=0;//go to firs value of vector
OK=0;//enable pin 6
}
x=sinPWM[i];// x take the value from vector corresponding to position i(i is zero indexed)
i=i+1;// go to the next position
if(OK==0){
OCR0B=0;//make pin 5 0
OCR0A=x;//enable pin 6 to corresponding duty cycle
}
if(OK==1){
OCR0A=0;//make pin 6 0
OCR0B=x;//enable pin 5 to corresponding duty cycle
}
}

void loop() {
  Serial.println(digitalRead(2));
if(digitalRead(2)==1){
  TCNT1 = 0;
  
}
}

PWM and ZCD signal.PNG
PWM and ZCD signal.PNG1280×824 39.6 KB

PWM and signal to lock onto.PNG
PWM and signal to lock onto.PNG1280×824 37.2 KB

2

See my reply on your duplicate topic

3

Duplicate removed.

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4

I recommend, instead of poling Pin 2, use its interrupt capability and set your sinewave counter back to 0.

volatile int i;  // Must be 'volatile' so the compiler knows that an interrupt might change it at any time.

void setup()
{
  attachInterrupt(DigitalPinToInterrupt(2), ZeroCross, RISING);
}

void ZeroCross()
{
  i = 0;
}

Note: Since 'i' is longer than one byte you really should turn off interrupts while you fetch a copy of it. If you don't, you will get occasional glitches where you read one byte of 'i' and then the ISR sets 'i' to zero before you fetch the other byte.