////////////////////////////////////////////////////////////////////
// Author: RSP @KMUTNB
// Date: 2022-02-08
// File: nano_pwm_loopback_interrupt_demo.ino
////////////////////////////////////////////////////////////////////

// In order to the the code with the Arduino Nano board,
// connect the Arduino D2 and P5 pins together via a jumper wire.
#define PULSE_IN_PIN    (2)  // use Arduino D2 pin as digital input
#define PWM_OUT_PIN     (5)  // use Arduino D5 pin as PWM output

void setup() {
  pinMode( PULSE_IN_PIN, INPUT );
  pinMode( LED_BUILTIN, OUTPUT ); // use onboard LED pin as output
  attachInterrupt( digitalPinToInterrupt(PULSE_IN_PIN), isr, CHANGE );
  analogWrite( PWM_OUT_PIN, 2 ); //  2/256*1024 = 8 usec pulse width
}

void loop() {
}

#ifdef USE_SFR
void isr() {
  PINB = _BV(PINB5);
}
#else
void isr() {
  uint8_t new_value = digitalRead( PULSE_IN_PIN );
  // use the new logic value for output
  digitalWrite( LED_BUILTIN, new_value );
}
#endif

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