#include "TimerHelpers.h" // https://www.gammon.com.au/forum/?id=11504
// for https://forum.arduino.cc/t/two-pwm-signals-on-pins-9-and-10-with-input-on-a1-signals-need-to-be-180-degrees-apart/1280072/4?u=davex

const unsigned long duty = 30;

void setup() {
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);

  TCCR1A = 0;        // reset timer 1
  TCCR1B = 0;
  // set up Timer 1
  Timer1::setMode (8, Timer1::PRESCALE_256, Timer1::CLEAR_A_ON_COMPARE | Timer1::SET_B_ON_COMPARE);
  ICR1 = 31250; // 31250 -> 1Hz  Sets frequency with prescaler as f=F_CPU/PRESCALE/ICR/2
  //  ICR1 = 250; // 250 -> 32kHz w PRESCALE_1 Sets frequency with prescaler as f=F_CPU/PRESCALE/ICR/2

  TCNT1 = 0;         // reset counter
  OCR1A =  ICR1 * duty / 100;     // compare A register value
  //OCR1B = OCR1A;
  OCR1B =  ICR1 - OCR1A;   // compare B register value
  Serial.begin(115200);

  reportTimer1();
}

void loop() {
  static int lastADC = -1;
  int pot = analogRead(A0);
  if(pot != lastADC){ // change detection on potentiometer
    lastADC = pot;
    OCR1A = ICR1 * 1UL * pot/1023; // duty cycle
    OCR1B = ICR1 - OCR1A; // complement for inversion
    reportTimer1();
  }
}

void reportTimer1(void){
  Serial.print("TCCR1A:0b");
  Serial.println(TCCR1A, BIN);
  Serial.print("TCCR1B:0b");
  Serial.println(TCCR1B, BIN);
  Serial.print("ICR1:");
  Serial.println(ICR1);
  Serial.print("OCR1A:");
  Serial.println(OCR1A);
  Serial.print("OCR1B:");
  Serial.println(OCR1B);
  Serial.print("Duty:");
  Serial.println(OCR1A*100.0/ICR1,3);
  Serial.print("Freq:");
  Serial.print(F_CPU / 256.0 / ICR1 / 2, 4);
  Serial.println("Hz\n");
}