Ticker.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 #ifndef MBED_TICKER_H
00017 #define MBED_TICKER_H
00018 
00019 #include "drivers/TimerEvent.h"
00020 #include "platform/Callback.h"
00021 #include "platform/mbed_toolchain.h"
00022 #include "platform/NonCopyable.h"
00023 #include "platform/mbed_power_mgmt.h"
00024 #include "hal/lp_ticker_api.h"
00025 #include "platform/mbed_critical.h"
00026 
00027 namespace mbed {
00028 /** \addtogroup drivers */
00029 
00030 /** A Ticker is used to call a function at a recurring interval
00031  *
00032  *  You can use as many separate Ticker objects as you require.
00033  *
00034  * @note Synchronization level: Interrupt safe
00035  *
00036  * Example:
00037  * @code
00038  * // Toggle the blinking LED after 5 seconds
00039  *
00040  * #include "mbed.h"
00041  *
00042  * Ticker timer;
00043  * DigitalOut led1(LED1);
00044  * DigitalOut led2(LED2);
00045  *
00046  * int flip = 0;
00047  *
00048  * void attime() {
00049  *     flip = !flip;
00050  * }
00051  *
00052  * int main() {
00053  *     timer.attach(&attime, 5);
00054  *     while(1) {
00055  *         if(flip == 0) {
00056  *             led1 = !led1;
00057  *         } else {
00058  *             led2 = !led2;
00059  *         }
00060  *         wait(0.2);
00061  *     }
00062  * }
00063  * @endcode
00064  * @ingroup drivers
00065  */
00066 class Ticker : public TimerEvent, private NonCopyable<Ticker> {
00067 
00068 public:
00069     Ticker() : TimerEvent(), _function(0), _lock_deepsleep(true)
00070     {
00071     }
00072 
00073     // When low power ticker is in use, then do not disable deep sleep.
00074     Ticker(const ticker_data_t *data) : TimerEvent(data), _function(0), _lock_deepsleep(true)
00075     {
00076 #if DEVICE_LPTICKER
00077         _lock_deepsleep = (data != get_lp_ticker_data());
00078 #endif
00079     }
00080 
00081     /** Attach a function to be called by the Ticker, specifying the interval in seconds
00082      *
00083      *  @param func pointer to the function to be called
00084      *  @param t the time between calls in seconds
00085      */
00086     void attach(Callback<void()> func, float t)
00087     {
00088         attach_us(func, t * 1000000.0f);
00089     }
00090 
00091     /** Attach a member function to be called by the Ticker, specifying the interval in seconds
00092      *
00093      *  @param obj pointer to the object to call the member function on
00094      *  @param method pointer to the member function to be called
00095      *  @param t the time between calls in seconds
00096      *  @deprecated
00097      *      The attach function does not support cv-qualifiers. Replaced by
00098      *      attach(callback(obj, method), t).
00099      */
00100     template<typename T, typename M>
00101     MBED_DEPRECATED_SINCE("mbed-os-5.1",
00102                           "The attach function does not support cv-qualifiers. Replaced by "
00103                           "attach(callback(obj, method), t).")
00104     void attach(T *obj, M method, float t)
00105     {
00106         attach(callback(obj, method), t);
00107     }
00108 
00109     /** Attach a function to be called by the Ticker, specifying the interval in microseconds
00110      *
00111      *  @param func pointer to the function to be called
00112      *  @param t the time between calls in micro-seconds
00113      *
00114      *  @note setting @a t to a value shorter than it takes to process the ticker callback
00115      *  causes the system to hang. Ticker callback is called constantly with no time
00116      *  for threads scheduling.
00117      *
00118      */
00119     void attach_us(Callback<void()> func, us_timestamp_t t)
00120     {
00121         core_util_critical_section_enter();
00122         // lock only for the initial callback setup and this is not low power ticker
00123         if (!_function && _lock_deepsleep) {
00124             sleep_manager_lock_deep_sleep();
00125         }
00126         _function = func;
00127         setup(t);
00128         core_util_critical_section_exit();
00129     }
00130 
00131     /** Attach a member function to be called by the Ticker, specifying the interval in microseconds
00132      *
00133      *  @param obj pointer to the object to call the member function on
00134      *  @param method pointer to the member function to be called
00135      *  @param t the time between calls in microseconds
00136      *  @deprecated
00137      *      The attach_us function does not support cv-qualifiers. Replaced by
00138      *      attach_us(callback(obj, method), t).
00139      */
00140     template<typename T, typename M>
00141     MBED_DEPRECATED_SINCE("mbed-os-5.1",
00142                           "The attach_us function does not support cv-qualifiers. Replaced by "
00143                           "attach_us(callback(obj, method), t).")
00144     void attach_us(T *obj, M method, us_timestamp_t t)
00145     {
00146         attach_us(Callback<void()>(obj, method), t);
00147     }
00148 
00149     virtual ~Ticker()
00150     {
00151         detach();
00152     }
00153 
00154     /** Detach the function
00155      */
00156     void detach();
00157 
00158 #if !defined(DOXYGEN_ONLY)
00159 protected:
00160     void setup(us_timestamp_t t);
00161     virtual void handler();
00162 
00163 protected:
00164     us_timestamp_t         _delay;  /**< Time delay (in microseconds) for resetting the multishot callback. */
00165     Callback<void()>    _function;  /**< Callback. */
00166     bool          _lock_deepsleep;  /**< Flag which indicates if deep sleep should be disabled. */
00167 #endif
00168 };
00169 
00170 } // namespace mbed
00171 
00172 #endif