Simple code to setup, increment and print Timer/Counter5 on pin47/PL2/T5

ArduinoMEGA_CounterT5.cpp

// Arduino Mega (2560) Platform.io
//Simple code to setup, increment and print Timer/Counter5 on pin47/PL2/T5

#include <Arduino.h>

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  TCCR5A=0; //Timer/Counter 5 Control Register A
  TCCR5B=0; //Timer/Counter 5 Control Register B
  TCNT5=0; //Reset timer5 register value to 0

  //Bit 2:0 – CSn2:0: Clock Select. 
  //7(b111): clock on rising edge. 
  //6(b110): clock on falling edge 
  TCCR5B = TCCR5B | 7; 
}

void loop() {
  // put your main code here, to run repeatedly:
  uint16_t counter5 = TCNT5;
  Serial.print("counter5: ");
  Serial.println(counter5);
  delay(1000);
}

Some credit goes to this post https://forum.arduino.cc/t/connecting-encoder-channel-a-to-hardware-counter/22431/3