InterruptIn
InterruptIn class hierarchy
Use the InterruptIn interface to trigger an event when a digital input pin changes. You can trigger interrupts on the rising edge (change from 0 to 1) or falling edge (change from 1 to 0) of signals.
InterruptIn class reference
| Public Member Functions | |
| InterruptIn (PinName pin) | |
| Create an InterruptIn connected to the specified pin. More... | |
| InterruptIn (PinName pin, PinMode mode) | |
| Create an InterruptIn connected to the specified pin, and the pin configured to the specified mode. More... | |
| int | read () |
| Read the input, represented as 0 or 1 (int) More... | |
| operator int () | |
| An operator shorthand for read() More... | |
| void | rise (Callback< void()> func) |
| Attach a function to call when a rising edge occurs on the input. More... | |
| void | fall (Callback< void()> func) |
| Attach a function to call when a falling edge occurs on the input. More... | |
| void | mode (PinMode pull) |
| Set the input pin mode. More... | |
| void | enable_irq () |
| Enable IRQ. More... | |
| void | disable_irq () |
| Disable IRQ. More... | |
Warnings:
-
No blocking code in ISR: avoid any call to wait, infinite while loop or blocking calls in general.
-
No printf, malloc or new in ISR: avoid any call to bulky library functions. In particular, certain library functions (such as printf, malloc and new) are non re-entrant, and their behavior could be corrupted when called from an ISR.
-
For
printfsfrom interrupt context, use Event instead.
Related
To read an input, see DigitalIn.
InterruptIn hello, world
/*
* Copyright (c) 2017-2020 Arm Limited and affiliates.
* SPDX-License-Identifier: Apache-2.0
*/
#include "mbed.h"
InterruptIn button(SW2);
DigitalOut led(LED1);
DigitalOut flash(LED_RED);
void flip()
{
led = !led;
}
int main()
{
button.rise(&flip); // attach the address of the flip function to the rising edge
while (1) { // wait around, interrupts will interrupt this!
flash = !flash;
ThisThread::sleep_for(250);
}
}
InterruptIn example
Try the following example to count rising edges on a pin.
/*
* Copyright (c) 2017-2020 Arm Limited and affiliates.
* SPDX-License-Identifier: Apache-2.0
*/
#include "mbed.h"
class Counter {
public:
Counter(PinName pin) : _interrupt(pin) // create the InterruptIn on the pin specified to Counter
{
_interrupt.rise(callback(this, &Counter::increment)); // attach increment function of this counter instance
}
void increment()
{
_count++;
}
int read()
{
return _count;
}
private:
InterruptIn _interrupt;
volatile int _count;
};
Counter counter(SW2);
int main()
{
while (1) {
printf("Count so far: %d\n", counter.read());
ThisThread::sleep_for(2000);
}
}