Advanced I/O

tone(), pulseIn(), shiftOut(), shiftIn(). More...

Functions
void	tone (uint8_t _pin, unsigned int frequency, unsigned long duration=0)
	Plays a square wave (50 % duty) on a pin, for a buzzer or speaker.
void	noTone (uint8_t _pin)
	Stops the tone, if one is playing on this pin.
unsigned long	pulseIn (pin_size_t pin, uint8_t state, unsigned long timeout)
	Measures how long a pulse on a pin lasts.
unsigned long	pulseInLong (pin_size_t pin, uint8_t state, unsigned long timeout)
	Same as pulseIn(); kept for Arduino compatibility.
void	shiftOut (pin_size_t dataPin, pin_size_t clockPin, BitOrder bitOrder, uint8_t val)
	Sends a byte one bit at a time, pulsing the clock pin after each bit.
uint8_t	shiftIn (pin_size_t dataPin, pin_size_t clockPin, BitOrder bitOrder)
	Reads a byte one bit at a time, pulsing the clock pin for each bit.

Detailed Description

tone(), pulseIn(), shiftOut(), shiftIn().

Function Documentation

noTone()

void noTone

(

uint8_t

_pin

)

Stops the tone, if one is playing on this pin.

Parameters

_pin	Arduino pin.

pulseIn()

unsigned long pulseIn	(	pin_size_t	pin,
		uint8_t	state,
		unsigned long	timeout = 1000000L )

Measures how long a pulse on a pin lasts.

If the pin is already at state, waits for that pulse to end first, then times the next one. Timing uses the microsecond timer, so it is accurate even with interrupts running. Blocks until the pulse ends or the timeout.

Parameters

pin	Arduino pin (an input).
state	HIGH to time a high pulse, LOW for a low pulse.
timeout	Longest time to wait for the whole measurement, in µs; 1000000 (1 s) by default.

Returns

Pulse length in µs, or 0 on timeout or for A3-A5.

pulseInLong()

unsigned long pulseInLong	(	pin_size_t	pin,
		uint8_t	state,
		unsigned long	timeout = 1000000L )

Same as pulseIn(); kept for Arduino compatibility.

Parameters

pin	Arduino pin (an input).
state	HIGH or LOW.
timeout	Longest time to wait, in µs; 1000000 (1 s) by default.

Returns

Pulse length in µs, or 0 on timeout.

shiftIn()

uint8_t shiftIn	(	pin_size_t	dataPin,
		pin_size_t	clockPin,
		BitOrder	bitOrder )

Reads a byte one bit at a time, pulsing the clock pin for each bit.

For shift registers such as the 74HC165. Set the clock pin to OUTPUT and the data pin to INPUT first. Each bit is read while the clock is high.

Parameters

dataPin	Arduino pin for data.
clockPin	Arduino pin for the clock.
bitOrder	MSBFIRST or LSBFIRST.

Returns

Byte received.

shiftOut()

void shiftOut	(	pin_size_t	dataPin,
		pin_size_t	clockPin,
		BitOrder	bitOrder,
		uint8_t	val )

Sends a byte one bit at a time, pulsing the clock pin after each bit.

For shift registers such as the 74HC595. Set both pins to OUTPUT first. The data bit is set while the clock is low and read by the chip on the rising edge.

Parameters

dataPin	Arduino pin for data.
clockPin	Arduino pin for the clock.
bitOrder	MSBFIRST or LSBFIRST.
val	Byte to send.

tone()

void tone	(	uint8_t	_pin,
		unsigned int	frequency,
		unsigned long	duration = 0 )

Plays a square wave (50 % duty) on a pin, for a buzzer or speaker.

Returns at once; the tone plays in the background. Only one tone plays at a time: starting a tone stops the previous one, on any pin. When it stops, the pin becomes an input.

The tone uses the pin's PWM slice, so it also changes the frequency of analogWrite() on the other pins of that slice (see analogWrite()).

Parameters

_pin	Arduino pin. A3-A5 and numbers out of range are ignored.
frequency	Frequency in Hz; 0 is ignored. The lowest is about 8 Hz at the default 133 MHz CPU speed.
duration	Length in ms; 0 (the default) plays until noTone().

Examples

AnalogBurst.ino.