Ticker.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2019 ARM Limited
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 #ifndef MBED_TICKER_H
00018 #define MBED_TICKER_H
00019 
00020 #include <mstd_utility>
00021 #include "drivers/TimerEvent.h"
00022 #include "platform/Callback.h"
00023 #include "platform/mbed_toolchain.h"
00024 #include "platform/NonCopyable.h"
00025 #include "hal/lp_ticker_api.h"
00026 
00027 namespace mbed {
00028 /**
00029  * \defgroup drivers_Ticker Ticker class
00030  * \ingroup drivers-public-api-ticker
00031  * @{
00032  */
00033 
00034 /** A Ticker is used to call a function at a recurring interval
00035  *
00036  *  You can use as many separate Ticker objects as you require.
00037  *
00038  * @note Synchronization level: Interrupt safe
00039  *
00040  * Example:
00041  * @code
00042  * // Toggle the blinking LED after 5 seconds
00043  *
00044  * #include "mbed.h"
00045  *
00046  * Ticker timer;
00047  * DigitalOut led1(LED1);
00048  * DigitalOut led2(LED2);
00049  *
00050  * int flip = 0;
00051  *
00052  * void attime() {
00053  *     flip = !flip;
00054  * }
00055  *
00056  * int main() {
00057  *     timer.attach(&attime, 5);
00058  *     while(1) {
00059  *         if(flip == 0) {
00060  *             led1 = !led1;
00061  *         } else {
00062  *             led2 = !led2;
00063  *         }
00064  *         wait(0.2);
00065  *     }
00066  * }
00067  * @endcode
00068  */
00069 class Ticker : public TimerEvent, private NonCopyable<Ticker> {
00070 
00071 public:
00072     Ticker();
00073 
00074     // When low power ticker is in use, then do not disable deep sleep.
00075     Ticker(const ticker_data_t *data);
00076 
00077     /** Attach a function to be called by the Ticker, specifying the interval in seconds
00078      *
00079      *  The method forwards its arguments to attach_us() rather than copying them which
00080      *  may not be trivial depending on the callback copied.
00081      *  The function is forcibly inlined to not use floating-point operations. This is
00082      *  possible given attach_us() expects an integer value for the callback interval.
00083      *  @param func pointer to the function to be called
00084      *  @param t the time between calls in seconds
00085      */
00086 #if defined(__ICCARM__)
00087     MBED_FORCEINLINE template <typename F>
00088 #else
00089     template <typename F> MBED_FORCEINLINE
00090 #endif
00091     void attach(F &&func, float t)
00092     {
00093         attach_us(std::forward<F>(func), t * 1000000.0f);
00094     }
00095 
00096     /** Attach a member function to be called by the Ticker, specifying the interval in seconds
00097      *
00098      *  @param obj pointer to the object to call the member function on
00099      *  @param method pointer to the member function to be called
00100      *  @param t the time between calls in seconds
00101      *  @deprecated
00102      *      The attach function does not support cv-qualifiers. Replaced by
00103      *      attach(callback(obj, method), t).
00104      */
00105     template<typename T, typename M>
00106     MBED_DEPRECATED_SINCE("mbed-os-5.1",
00107                           "The attach function does not support cv-qualifiers. Replaced by "
00108                           "attach(callback(obj, method), t).")
00109     void attach(T *obj, M method, float t)
00110     {
00111         attach(callback(obj, method), t);
00112     }
00113 
00114     /** Attach a function to be called by the Ticker, specifying the interval in microseconds
00115      *
00116      *  @param func pointer to the function to be called
00117      *  @param t the time between calls in micro-seconds
00118      *
00119      *  @note setting @a t to a value shorter than it takes to process the ticker callback
00120      *  causes the system to hang. Ticker callback is called constantly with no time
00121      *  for threads scheduling.
00122      *
00123      */
00124     void attach_us(Callback<void()> func, us_timestamp_t t);
00125 
00126     /** Attach a member function to be called by the Ticker, specifying the interval in microseconds
00127      *
00128      *  @param obj pointer to the object to call the member function on
00129      *  @param method pointer to the member function to be called
00130      *  @param t the time between calls in microseconds
00131      *  @deprecated
00132      *      The attach_us function does not support cv-qualifiers. Replaced by
00133      *      attach_us(callback(obj, method), t).
00134      */
00135     template<typename T, typename M>
00136     MBED_DEPRECATED_SINCE("mbed-os-5.1",
00137                           "The attach_us function does not support cv-qualifiers. Replaced by "
00138                           "attach_us(callback(obj, method), t).")
00139     void attach_us(T *obj, M method, us_timestamp_t t)
00140     {
00141         attach_us(Callback<void()>(obj, method), t);
00142     }
00143 
00144     virtual ~Ticker()
00145     {
00146         detach();
00147     }
00148 
00149     /** Detach the function
00150      */
00151     void detach();
00152 
00153 #if !defined(DOXYGEN_ONLY)
00154 protected:
00155     void setup(us_timestamp_t t);
00156     virtual void handler();
00157 
00158 protected:
00159     us_timestamp_t         _delay;  /**< Time delay (in microseconds) for resetting the multishot callback. */
00160     Callback<void()>    _function;  /**< Callback. */
00161     bool          _lock_deepsleep;  /**< Flag which indicates if deep sleep should be disabled. */
00162 #endif
00163 };
00164 
00165 /** @}*/
00166 
00167 } // namespace mbed
00168 
00169 #endif