Main.cpp

#include <Arduino.h>
#include <M5Unified.h>

int counter1 = 0;

void setup() {
  auto cfg = M5.config();
  M5.begin(cfg);
  delay(500);

  M5.Display.setTextSize(2);
}

void loop() {
  M5.update();

  M5.Display.setCursor(0, 20);
  M5.Display.print("C1: ");
  M5.Display.print(counter1);

  Serial.println(counter1);
  delay(200);

  counter1++;
}

Platform.ini

[env:m5stack-atoms3]
platform = espressif32
board = m5stack-atoms3
framework = arduino
monitor_speed = 115200
monitor_rts = 0
monitor_dtr = 0
monitor_raw = yes
lib_deps = m5stack/M5Unified@^0.1.13