Phase shifting.

[pito]

This program is producing 2 rectangular pulses, I need to regulate phase between them (between A and B ).

void setup()
{
    Serial.begin(9600);
    TCCR2A = 0x00;  //always reset
    TCCR2B = 0x00; //always reset
    TCCR2A = (1<<COM2A1)|(1<<COM2B1) | (0<<WGM21)|(1<<WGM20); //Mode-1
    TCCR2B = (1<<CS22)|(1<<CS21)|(0<<CS20)|(0<<WGM22); //Mode-1 and prescale 256
    pinMode(11, OUTPUT);  //Ch-A
    pinMode(3, OUTPUT);     //Ch-B
  
}

void loop()
{

}​

[Teleno]

I'm running it on Arduino Uno and I see a weak signal on pins 11 but none on pin 3. You haven't set the compare registers so they're at 0 and since the output mode you selected is clear on compare their ouput is always low.

In mode 1 (phase correct PWM) it's not possible to obtain pulses of the same width at different phases. You need normal mode (Mode 0) and toggle outpouts on compare.

Try this:

void setup()
{
    TCCR2A = 0x00;  //always reset
    TCCR2B = 0x00; //always reset
    TCCR2A = (1<<COM2A0)|(1<<COM2B0); //Mode-1
    OCR2A = 0;
    OCR2B = 128; // Default: 90 degrees phase
    TCCR2B = (1<<CS22)|(1<<CS21)|(0<<CS20); //Mode-1 and prescale 256
    pinMode(11, OUTPUT);  //Ch-A
    pinMode(3, OUTPUT);     //Ch-B
}
unsigned int setPhaseB(unsigned int degrees){
  OCR2B = (128 * degrees)/90 - 1;
}
void loop()
{
  for (unsigned int x = 0; x <= 180; x++){
    setPhaseB(x);
    delay(30);
  }
}​ 

[pito]

Thanks, it is working, now I need to add buttons to do the phase shift Left /Right

[Teleno]

The're a problem in that when chanfing the phase the wave can suddenly invert (flip polarity) from its assigned phase-angle.

This code prevents polarity flipping.

void setup()
{
    pinMode(11, OUTPUT);  //Ch-A
    pinMode(3, OUTPUT);   //Ch-B
    digitalWrite(11, LOW);
    digitalWrite(3, LOW);
    TCCR2A = 0x00;  //always reset
    TCCR2B = 0x00;  //always reset
    TCCR2A = (1<<COM2A0)|(1<<COM2B0); //Mode-0
    OCR2A = 0;
    OCR2B = 1; // Default: 90 degrees phase
    TCCR2B = (1<<CS20); //Mode-1 and prescale 256
}
unsigned int setPhaseB(uint8_t n){
  // wait for a timer overflow before changing phase
  TIFR2 |= (1<<TOV2); // clear overflow flag
  while( (TIFR2 & (1<<TOV2)) != 1 );  // wait for overflow
  TCCR2B &= ~((1<<CS22) | (1<<CS21) | (1<<CS20)); // stop timer
  // if both channels are in the same state, force toggle channel B
  if ((PINB ^ PIND) & (1 << PIN3)) {
        // force compare match
        TCCR2B |= (1<<FOC2B);
  }
  TCNT2 = 0;
  if (n < 1) OCR2B=1; // constraint to prevent phase flipping
  else OCR2B = n;
  // restart timer
  TCCR2B = (1<<CS20);
}
void loop()
{
  for (uint8_t x = 1; x < 255; x++){
    setPhaseB(x);
    delay(10);
  }
  for (uint8_t x = 255; x > 0; x--){
    setPhaseB(x);
    delay(10);
  }
}
​ 

[pito]

I added buttons but I don't know what to do with this part

 for (uint8_t x = 1; x < 255; x++){
    setPhaseB(x);
    delay(10);
  }
  for (uint8_t x = 255; x > 0; x--){
    setPhaseB(x);
    delay(10);
  }​

void setup()
{
  //++++++++++++++++++++++++++++++++++++
  Serial.begin(115200);
  pinMode(7, INPUT_PULLUP);
  pinMode(8, INPUT_PULLUP);
  pinMode(9, INPUT_PULLUP);
  //+++++++++++++++++++++++++++++++++++++
  pinMode(11, OUTPUT);  //Ch-A
  pinMode(3, OUTPUT);   //Ch-B
  digitalWrite(11, LOW);
  digitalWrite(3, LOW);
  TCCR2A = 0x00;  //always reset
  TCCR2B = 0x00;  //always reset
  TCCR2A = (1 << COM2A0) | (1 << COM2B0); //Mode-0
  OCR2A = 0;
  OCR2B = 1; // Default: 90 degrees phase
  TCCR2B = (1 << CS20); //Mode-1 and prescale 256
}
unsigned int setPhaseB(uint8_t n) {
  // wait for a timer overflow before changing phase
  TIFR2 |= (1 << TOV2); // clear overflow flag
  while ( (TIFR2 & (1 << TOV2)) != 1 ); // wait for overflow
  TCCR2B &= ~((1 << CS22) | (1 << CS21) | (1 << CS20)); // stop timer
  // if both channels are in the same state, force toggle channel B
  if ((PINB ^ PIND) & (1 << PIN3)) {
    // force compare match
    TCCR2B |= (1 << FOC2B);
  }
  TCNT2 = 0;
  if (n < 1) OCR2B = 1; // constraint to prevent phase flipping
  else OCR2B = n;
  // restart timer
  TCCR2B = (1 << CS20);
}
void loop()
{

  //+++++++++++++++++++++++++++++++++
  if (digitalRead(8) == 0) {
    x++;


  }
  if (digitalRead(9) == 0) {
    x--;

  }
  if (digitalRead(7) == 0)
  {
    EEPROM.write(500, x);
  }
  //++++++++++++++++++++++++++++++++
  for (uint8_t x = 1; x < 255; x++) {
    setPhaseB(x);
    delay(10);
  }
  for (uint8_t x = 255; x > 0; x--) {
    setPhaseB(x);
    delay(10);
  }
  Serial.print(" x= ");
  Serial.println(x);
}​

[Teleno]

See if this works

#include <EEPROM.h>

#define DEFAULT_PHASE 128 // 90 degrees
uint8_t phase = DEFAULT_PHASE;
uint8_t lastRead_7, lastRead_8, lastRead_9 = 1;
void setup()
{
    pinMode(11, OUTPUT);  //Ch-A
    pinMode(3, OUTPUT);   //Ch-B
    digitalWrite(11, LOW);
    digitalWrite(3, LOW);
    TCCR2A = 0x00;  //always reset
    TCCR2B = 0x00;  //always reset
    TCCR2A = (1<<COM2A0)|(1<<COM2B0); //Mode-0 (Normal mode)
    OCR2A = 0;
    OCR2B = DEFAULT_PHASE;
    TCCR2B = (1<<CS20); //Mode-1 and prescale 256
}
unsigned int setPhaseB(uint8_t n){
  // wait for a timer overflow before changing phase
  TIFR2 |= (1<<TOV2); // clear overflow flag
  while( (TIFR2 & (1<<TOV2)) != 1 );  // wait for overflow
  TCCR2B &= ~((1<<CS22) | (1<<CS21) | (1<<CS20)); // stop timer
  // if both channels are in the same state, force toggle channel B
  if ((PINB ^ PIND) & (1 << PIN3)) {
    // force compare match (toggle B)
    TCCR2B |= (1<<FOC2B);
  }
  // back to zero
  TCNT2 = 0;
  if (n < 1) OCR2B=1; // constraint to prevent phase flipping
  else OCR2B = n;
  // restart timer
  TCCR2B = (1<<CS20);
}
void loop()
{
  uint8_t read = digitalRead(8);
  if ( (read == 0) & (lastRead_8 == 1) ) {
    setPhaseB(phase++);
    lastRead_8 = read;
  }
  read = digitalRead(9);
  if ( (read == 0) & (lastRead_9 == 1) ) {
    setPhaseB(phase--);
    lastRead_9 = read;
  }
  read = digitalRead(7);
  if ( (read == 0) & (lastRead_7 == 1) ) {
    lastRead_7 = read;
    EEPROM.write(500, phase);
  }
  Serial.print(" phase= ");
  Serial.println(phase);
}
​ 

[Teleno]

This works for me but each button push just changes the phase by 1.

//#include <EEPROM.h>
#define DEFAULT_PHASE 128 // 90 degrees
uint8_t phase = DEFAULT_PHASE;
uint8_t lastRead_7, lastRead_8, lastRead_9 = 1;
void setup()
{
    pinMode(11, OUTPUT);  //Ch-A
    pinMode(3, OUTPUT);   //Ch-B
    digitalWrite(11, LOW);
    digitalWrite(3, LOW);
    TCCR2A = 0x00;  //always reset
    TCCR2B = 0x00;  //always reset
    TCCR2A = (1<<COM2A0)|(1<<COM2B0); //Mode-0 (Normal mode)
    OCR2A = 0;
    OCR2B = DEFAULT_PHASE;
    TCCR2B = (1<<CS20); //Mode-1 and prescale 256
    // keys
    pinMode(7, INPUT_PULLUP);
    pinMode(8, INPUT_PULLUP);
    Serial.begin(9600);
}
unsigned int setPhaseB(uint8_t n){
  // wait for a timer overflow before changing phase
  TIFR2 |= (1<<TOV2); // clear overflow flag
  while( (TIFR2 & (1<<TOV2)) != 1 );  // wait for overflow
  TCCR2B &= ~((1<<CS22) | (1<<CS21) | (1<<CS20)); // stop timer
  // if both channels are in the same state, force toggle channel B
  if ((PINB ^ PIND) & (1 << PIN3)) {
    // force compare match (toggle B)
    TCCR2B |= (1<<FOC2B);
  }
  // back to zero
  TCNT2 = 0;
  if (n < 1) OCR2B=1; // constraint to prevent phase flipping
  else OCR2B = n;
  // restart timer
  TCCR2B = (1<<CS20);
}
void loop()
{
  uint8_t read = digitalRead(8);
  if ( (read == 0) & (lastRead_8 == 1) ) {
    phase = (phase < 255)? phase++;
    setPhaseB(phase);
    Serial.print(" phase= ");
    Serial.println(phase);
  }
  lastRead_8 = read;
  read = digitalRead(9);
  if ( (read == 0) & (lastRead_9 == 1) ) {
    phase = (phase > 1)? phase--;
    setPhaseB(phase);
    Serial.print(" phase= ");
    Serial.println(phase);
  }
  lastRead_9 = read;
  read = digitalRead(7);
  if ( (read == 0) & (lastRead_7 == 1) ) {
    EEPROM.write(500, phase);
  }
  lastRead_7 = read;
}
​ 

[pito]

For some reason pinMode(x, INPUT_PULLUP); is not working, there is 1V on pins not 5V.

[pito]

oops, you are using 7 and 8 I was using 8 and 9 , = testing

[pito]

Shifting is working from 0 to 180 deg, I need 0 to 360 deg with limits , if phase > 361 phase =0, if phase <0 phase = 360.

[Teleno]

Shifting is working from 0 to 180 deg, I need 0 to 360 deg with limits , if phase > 361 phase =0, if phase <0 phase = 360.

In-phase = 0 degrees
Quadreature: 90 gegrees
opposite phase = 180 degrees.

180 degrees is the maximum phase shift achievable.

[pito]

How about changing the pulse width?
Here is my concept of coil nulling.

[Gunghouk]

Please see my post regarding an asymetrical pulse pattern generator.
If your waveform was represented by a single bit in a 360 byte array then rotating it one position up or down within the array would move it by +/1 degree.

ie. 180 hi then 180 lo for say bit0 repeatedly clocked/indexed out at whatever rate your processor can handle reliably.

Actually this sounds like a shift register!

My 2 cents.

[Gunghouk]

Please see my post regarding an asymetrical pulse pattern generator.
If your waveform was represented by a single bit in a 360 byte array then rotating it one position up or down within the array would move it by +/1 degree.

ie. 180 hi then 180 lo for say bit0 repeatedly clocked/indexed out at whatever rate your processor can handle reliably.

My 2 cents.

Hmm...... Could this be just a shift register for your application?