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 
00024 namespace mbed {
00025 /** \addtogroup drivers */
00026 
00027 /** A Ticker is used to call a function at a recurring interval
00028  *
00029  *  You can use as many seperate Ticker objects as you require.
00030  *
00031  * @note Synchronization level: Interrupt safe
00032  *
00033  * Example:
00034  * @code
00035  * // Toggle the blinking led after 5 seconds
00036  *
00037  * #include "mbed.h"
00038  *
00039  * Ticker timer;
00040  * DigitalOut led1(LED1);
00041  * DigitalOut led2(LED2);
00042  *
00043  * int flip = 0;
00044  *
00045  * void attime() {
00046  *     flip = !flip;
00047  * }
00048  *
00049  * int main() {
00050  *     timer.attach(&attime, 5);
00051  *     while(1) {
00052  *         if(flip == 0) {
00053  *             led1 = !led1;
00054  *         } else {
00055  *             led2 = !led2;
00056  *         }
00057  *         wait(0.2);
00058  *     }
00059  * }
00060  * @endcode
00061  * @ingroup drivers
00062  */
00063 class Ticker : public TimerEvent, private NonCopyable<Ticker> {
00064 
00065 public:
00066     Ticker() : TimerEvent() {
00067     }
00068 
00069     Ticker(const ticker_data_t *data) : TimerEvent(data) {
00070         data->interface->init();
00071     }
00072 
00073     /** Attach a function to be called by the Ticker, specifiying the interval in seconds
00074      *
00075      *  @param func pointer to the function to be called
00076      *  @param t the time between calls in seconds
00077      */
00078     void attach(Callback<void()> func, float t) {
00079         attach_us(func, t * 1000000.0f);
00080     }
00081 
00082     /** Attach a member function to be called by the Ticker, specifiying the interval in seconds
00083      *
00084      *  @param obj pointer to the object to call the member function on
00085      *  @param method pointer to the member function to be called
00086      *  @param t the time between calls in seconds
00087      *  @deprecated
00088      *      The attach function does not support cv-qualifiers. Replaced by
00089      *      attach(callback(obj, method), t).
00090      */
00091     template<typename T, typename M>
00092     MBED_DEPRECATED_SINCE("mbed-os-5.1",
00093         "The attach function does not support cv-qualifiers. Replaced by "
00094         "attach(callback(obj, method), t).")
00095     void attach(T *obj, M method, float t) {
00096         attach(callback(obj, method), t);
00097     }
00098 
00099     /** Attach a function to be called by the Ticker, specifiying the interval in micro-seconds
00100      *
00101      *  @param func pointer to the function to be called
00102      *  @param t the time between calls in micro-seconds
00103      */
00104     void attach_us(Callback<void()> func, us_timestamp_t t) {
00105         _function = func;
00106         setup(t);
00107     }
00108 
00109     /** Attach a member function to be called by the Ticker, specifiying the interval in micro-seconds
00110      *
00111      *  @param obj pointer to the object to call the member function on
00112      *  @param method pointer to the member function to be called
00113      *  @param t the time between calls in micro-seconds
00114      *  @deprecated
00115      *      The attach_us function does not support cv-qualifiers. Replaced by
00116      *      attach_us(callback(obj, method), t).
00117      */
00118     template<typename T, typename M>
00119     MBED_DEPRECATED_SINCE("mbed-os-5.1",
00120         "The attach_us function does not support cv-qualifiers. Replaced by "
00121         "attach_us(callback(obj, method), t).")
00122     void attach_us(T *obj, M method, us_timestamp_t t) {
00123         attach_us(Callback<void()>(obj, method), t);
00124     }
00125 
00126     virtual ~Ticker() {
00127         detach();
00128     }
00129 
00130     /** Detach the function
00131      */
00132     void detach();
00133 
00134 protected:
00135     void setup(us_timestamp_t t);
00136     virtual void handler();
00137 
00138 protected:
00139     us_timestamp_t         _delay;  /**< Time delay (in microseconds) for re-setting the multi-shot callback. */
00140     Callback<void()>    _function;  /**< Callback. */
00141 };
00142 
00143 } // namespace mbed
00144 
00145 #endif