Interrupt Pin

Hardware Interface

Defined in namespace hal

#include <libhal/interrupt_pin.hpp>

class interrupt_pin

Digital interrupt pin hardware abstraction.

Use this to automatically call a function when a pin’s state has transitioned.

The transition states are:

• falling edge: the pin reads a transitions from HIGH to LOW

• rising edge: the pin reads a transitions from LOW to HIGH

• both: the pin reads any state change

Subclassed by hal::soft::inert_interrupt_pin

Public Types

enum class trigger_edge

The condition in which an interrupt it’s triggered.

Values:

enumerator falling

Trigger the interrupt when a pin transitions from HIGH voltage to LOW voltage.

enumerator rising

Trigger the interrupt when a pin transitions from LOW voltage to HIGH voltage.

enumerator both

Trigger the interrupt when a pin transitions it state.

using handler = void(bool p_state)

Interrupt pin handler.

param p_state - if true state of the pin when the interrupt was triggered was HIGH, otherwise LOW

Public Functions

inline void configure(const settings &p_settings)

Configure the interrupt pin to match the settings supplied.

Parameters:

p_settings – - settings to apply to interrupt pin

Throws:

hal::operation_not_supported – - if the settings could not be achieved.

inline void on_trigger(hal::callback<handler> p_callback)

Set the callback for when the interrupt occurs.

Any state transitions before this function is called are lost.

Parameters:

p_callback – - function to execute when the trigger condition occurs.

struct settings

Generic settings for interrupt pins.

Public Members

pin_resistor resistor = pin_resistor::pull_up

Pull resistor for an interrupt pin.

In general, it is highly advised to either set the pull resistor to something other than “none” or to attach an external pull up resistor to the interrupt pin in order to prevent random interrupt from firing.

trigger_edge trigger = trigger_edge::rising

The trigger condition that will signal the system to run the callback.

Utilities

Defined in namespace hal

#include <libhal-util/interrupt_pin.hpp>

group InterruptPin

Functions

constexpr auto operator==(const interrupt_pin::settings &p_lhs, const interrupt_pin::settings &p_rhs)

Compares two interrupt pin states, compares both their trigger and resistor.

Parameters:

• p_lhs – An interrupt pin

• p_rhs – An interrupt pin

Returns:

A boolean if they are the same or not.