IrtcSquareWave() configures the RTC square-wave output.

bool IrtcSquareWave(bool enable, uint8_t frequency = IRTC_SQUARE_WAVE_1HZ, bool batteryPowered = false)

void setup() {
  if (!IrtcBegin()) return;
 
  // Output a 1Hz square wave on the INT/SQW terminal.
  IrtcSquareWave(true, IRTC_SQUARE_WAVE_1HZ);
}
 
void loop() {
}

Run each device's corresponding Begin command first. Check I²C addresses and pin sharing; if the bool return value is false, inspect wiring and power.

← Built-in Command List