40 Hz Square wave with 8kHz tone

[cedarlakeinstruments]

@wdunne

For the timer and using the noTone to turn it off, would this code generate what I am looking for?
void loop() {
tone(AudioPin, 8000);
delayMicroseconds(12500);
noTone(Audiopin);
delayMicroseconds(12500);
}

Why don't you just try it? Surely that's faster than posting it and waiting for an answer.