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Utility

This library is used for square wave generation, serial data I/O (software), and pulse width measurement.

tone

Description

Generates a square wave for the specified frequency. Useful for turning on a buzzer. You can set the frequency from 2 to 65535Hz and use multiple pins up to 15ch.

Syntax

tone(int pin, int frequency, int duration)

Parameters

pin: The pin on which to generate the tone
frequency: The frequency of the tone in Hertz [Hz]
duration: The duration of the tone in milliseconds (optional). Continues to buzz when abbreviated or set to 0.

Returns

Nothing

noTone

Description

Stops the generation of a square wave triggered by tone(). Has no effect if no tone is being generated.

Syntax

noTone(int pin)

Parameters

pin: The pin on which to stop generating the tone.

Returns

Nothing

shiftOut

Description

Shifts out a byte of data one bit at a time. Starts from either the most (the leftmost) or least (the rightmost) significant bit. Each bit is written in turn to a data pin, after which a clock pin is pulsed (taken high, then low) to indicate that the bit is available.

Syntax

shiftOut(int dataPin, int clockPin, bitOrder, unsigned char value)

Parameters

dataPin: The pin on which to output each bit
clockPin: The pin to toggle once the dataPin has been set to the correct value
bitOrder: Which order to shift out the bits; either MSBFIRST or LSBFIRST. (Most significant bit first, or, least significant bit first)
value: The data to shift out(unsigned char 8-bit data)

Returns

Nothing

shiftIn

Description

Shifts in a byte of data one bit at a time. Starts from either the most (the leftmost) or least (the rightmost) significant bit. For each bit, the clock pin is pulled high, the next bit is read from the data line, and then the clock pin is taken low.

Syntax

unsigned char shiftIn(unsigned char dataPin, unsigned char clockPin, bitOrder)

Parameters

dataPin: The pin on which to input each bit
clockPin: The pin to toggle to signal a read from the dataPin
bitOrder: Which order to shift in the bits; either MSBFIRST or LSBFIRST. (Most significant bit first, or, least significant bit first)

Returns

The value read (8-bit data)

pulseIn

Description

Reads a pulse (either HIGH or LOW) on a pin.

Syntax

unsigned long pulseIn(int pin, int val, unsigned long timeout = 1000000)

Parameters

pin: The number of the pin on which you want to read the pulse
val: Type of pulse to read: either HIGH or LOW
timeout (optional): The number of microseconds to wait for the pulse to start; default is one second (option)

Returns

The length of the pulse (in microseconds) or 0 if no pulse started before the timeout (unsigned long)

Sample for tone.

#include <Arduino.h>
void setup(){
    tone(3, 261);
    delay(500);
    tone(3, 293);
    delay(500);
    tone(3, 329);
    delay(500);
    noTone(3);
    delay(500);
}
  
void loop(){
}