Tone()
tone()
- Description
Produce a specific frequency square wave on a pin（50% duty ratio）. And the time of duration can be set, or the waveform will be produce all the time until the noTone() function is called. This pin can be connected with the piezoelectric buzzer or other horn to play the sound.
At one time, only one sound can be produced. If a pin is already playing music, the call of the tone() will have no effect. If music is played in the same pin, it will adjust the frequency automatically.
If use unction tone() , it will interfere with the PWM of pin3 and pin11（except Mega）.
Note：If you want different tones to be produced on multiple pins, you should call function noTone() to the next pin before calling function tone() to this pin.
- Syntax
tone(pin, frequency) tone(pin, frequency, duration)
- Parameters
pin：The pin to produce the sound
frequency: The frequency of the sound to be produced, in Hz, and unsigned int
duration：The time the sound lasts for, in milliseconds（optional），, and unsigned long
- Return
