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This page is intended as a reference for core developers only, and the content is only changed after a consensus has been reached through discussion of any such changes. Please use the Discussion page to talk about any changes or issues you have with the current implementation.
Classification Hardware interrupt control methods.
Suggested location WInterrupts.h
C++ required No
Timing constraints None
Version introduced 1.0 (0100)
Framework dependencies None
void interruptMode(uint8_t interruptNum, uint8_t mode)
Required? Yes
Issues None



The interruptMode() method sets the mode in which an external interrupt is generated.

Black Box Input

The number of the external interruption is provided. EXTERNAL_INTERRUPT_0, EXTERNAL_INTERRUPT_1… etc.

The mode the external interrupt is provided of either LOW, RISING, FALLING or RISING.

Black Box Output

If possible, the mode of the given external interruption is set to either LOW, RISING, FALLING or RISING. Nothing is returned.


None. Single function only.


It is possible to generate and attend external interrupts on the Wiring hardware. On Wiring v1 boards the external interrupts capable pins are: 0, 1, 2, 3, 36, 37, 38 and 39. On Wiring S board the external interrupts capable pins are: 2, 3 and 18. In addition to being regular digital pins, note that some of these pins are also used for libraries like Wire or Serial/Serial1.

External interrupts can be triggered at different stages in the value of a pin, LOW when a pin is low, CHANGE when the pin changes, RISING when the pin goes from low to high or FALLING when the pin goes from high to low.

Proposed Changes

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