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LowPowerTimeout

LowPowerTimeout class hierarchy

Use the LowPowerTimeout interface to set up an interrupt to call a function after a specified delay. You can create any number of LowPowerTimeout objects. This allows multiple outstanding interrupts at the same time.

Notes

  • 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 not re-entrant, and their behavior could be corrupted when called from an ISR.

LowPowerTimeout class reference

Public Types
using clock = LowPowerClock
 Clock to use with attach_absolute, guaranteeing running only while attached or manually locked. More...
using steady_clock = LowPowerClock
 Clock to use with attach_absolute, running always. More...
Public Member Functions
LowPowerClock::time_point scheduled_time () const
template<class F >
void attach_absolute (F &&func, LowPowerClock::time_point abs_time)
 Attach a function to be called by the Timeout, specifying the absolute time. More...
std::chrono::microseconds remaining_time () const
 Return time remaining until callback. More...
template<typename F >
MBED_FORCEINLINE void attach (F &&func, float t)
 Attach a function to be called by the Ticker, specifying the interval in seconds. More...
void attach (Callback< void()> func, std::chrono::microseconds t)
 Attach a function to be called by the Ticker, specifying the interval in microseconds. More...
void attach_us (Callback< void()> func, us_timestamp_t t)
 Attach a function to be called by the Ticker, specifying the interval in microseconds. More...
void detach ()
 Detach the function. More...

LowPowerTimeout example

Set up a time out to invert an LED after a given time:

/*
 * Copyright (c) 2020 Arm Limited and affiliates.
 * SPDX-License-Identifier: Apache-2.0
 */

#include "mbed.h"

LowPowerTimeout flipper;
DigitalOut led1(LED1);
DigitalOut led2(LED2);

void flip()
{
    led2 = !led2;
}

int main()
{
    led2 = 1;
    flipper.attach(&flip, 2.0); // setup flipper to call flip after 2 seconds

    // spin in a main loop. flipper will interrupt it to call flip
    while (1) {
        led1 = !led1;
        ThisThread::sleep_for(200);
    }
}

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