Interrupts

attachInterrupt(), detachInterrupt(), interrupts(), noInterrupts(). More...

Macros
#define	interrupts()
#define	noInterrupts()
#define	digitalPinToInterrupt(pin)

Functions
void	attachInterrupt (pin_size_t interruptNumber, voidFuncPtr callback, PinStatus mode)
	Calls a function when the level on a pin changes.
void	attachInterruptParam (pin_size_t interruptNumber, voidFuncPtrParam callback, PinStatus mode, void *param)
	Same as attachInterrupt(), but the function is called with param.
void	detachInterrupt (pin_size_t interruptNumber)
	Stops calling the function attached to a pin.

Detailed Description

attachInterrupt(), detachInterrupt(), interrupts(), noInterrupts().

Macro Definition Documentation

digitalPinToInterrupt

#define digitalPinToInterrupt

(

pin

)

Value:

(pin)

Interrupt number for attachInterrupt(): every pin can interrupt, so it is the pin itself.

interrupts

#define interrupts

(

)

Value:

__asm volatile("cpsie i" ::: "memory")

Enables interrupts again after noInterrupts().

noInterrupts

#define noInterrupts

(

)

Value:

__asm volatile("cpsid i" ::: "memory")

Disables interrupts, for example while reading a variable an interrupt changes. Keep the section short: USB Serial, attachInterrupt() functions and tone() durations wait until interrupts() (millis() keeps counting). Only the calling core is affected: the other core keeps running (Multicore).

Function Documentation

attachInterrupt()

void attachInterrupt	(	pin_size_t	interruptNumber,
		voidFuncPtr	callback,
		PinStatus	mode )

Calls a function when the level on a pin changes.

Unlike an Uno (D2 and D3 only), every pin except A3-A5 can interrupt. Replaces any function already attached to the pin.

Parameters

interruptNumber	digitalPinToInterrupt(pin), which is just the pin number.
callback	Function to call; nullptr is ignored.
mode	RISING, FALLING or CHANGE; or LOW or HIGH, which call the function again as soon as it returns, for as long as the level lasts.

Warning

The function runs inside the interrupt: keep it short, make variables it shares with loop() volatile, and do not use Serial or delay() in it.

attachInterruptParam()

void attachInterruptParam	(	pin_size_t	interruptNumber,
		voidFuncPtrParam	callback,
		PinStatus	mode,
		void *	param )

Same as attachInterrupt(), but the function is called with param.

Parameters

interruptNumber	digitalPinToInterrupt(pin), which is just the pin number.
callback	Function taking a void*; nullptr is ignored.
mode	As for attachInterrupt().
param	Passed to callback on every call.

detachInterrupt()

void detachInterrupt

(

pin_size_t

interruptNumber

)

Stops calling the function attached to a pin.

Parameters

interruptNumber

digitalPinToInterrupt(pin), which is just the pin number.