Offset sinewave generation for testing PWM open drain circuitry

offset_sinewave.ino

const int num_pwm_pins = 4;
const int pwm_pins[ num_pwm_pins ] = { 9, 10, 11, 13 };
uint8_t tick_count = 0;

void setup() {
  for( uint8_t i=0; i<num_pwm_pins; i++ ){
    pinMode( pwm_pins[ i ],  OUTPUT );
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  for( uint8_t i=0; i<num_pwm_pins; i++ ){
    analogWrite( pwm_pins[ i ], (uint8_t)( 127.f * ( 1.f - cos( TWO_PI * (( (float)tick_count / 255.f) + ( (float)i / (float)num_pwm_pins ))))));
  }
  tick_count++; // we utilise overflow here deliberately
  delay(10);
}