Interrupt

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This library allows users to trigger a process interrupt function or enable/disable an interrupt function when the input to a pin changes value.

attachInterrupt

Description

Specifies a function to execute (call) when an external interrupt occurs (signal on external pin).

Syntax

attachInterrupt(pin, void(*)(void) func, mode)

Parameters

pin: The number of pin used for the interrupt(part of IntX in pin map)
func: The function to call when the interrupt occurs
mode:
  LOW (to trigger the interrupt whenever the pin is low)
  CHANGE (to trigger the interrupt whenever the pin changes value)
  FALLING (to trigger when the pin goes from high to low)
  RISING (to trigger when the pin goes from low to high)

Returns

None

detachInterrupt

Description

Turns off the interrupt specified in attachInterrupt.

Syntax

detatachInterrupt(pin)

Parameters

pin: The number of pin used for the interrupt (part of IntX in pin map)

Returns

None

interrupts

Description

Re-enables the interrupt disabled in noInterrupts.

Syntax

interrupts()

Parameters

None

Returns

None

noInterrupts

Description

Disables an interrupt process. Use this when you need to protect the timing of a specific process; this can even be used to disable an important task run in the background.

Syntax

noInterrupts()

Parameters

None

Returns

None

This is a sample that generates an interrupt when the state if pin 0 changes, which in turn changes the state of the LED.

#include <Arduino.h>
int ledpin = PIN_LED0;
int intpin = 1;
bool state = LOW;
void blink()
{
  state = !state;
}
   
void setup()
{
  pinMode(ledpin, OUTPUT);
  pinMode(intpin, INPUT_PULLUP);
  
  attachInterrupt(0, blink, CHANGE);
}
   
void loop()
{
  digitalWrite(ledpin, state);
}