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 "TimerEvent.h"
00020 #include "Callback.h"
00021 
00022 namespace mbed {
00023 
00024 /** A Ticker is used to call a function at a recurring interval
00025  *
00026  *  You can use as many seperate Ticker objects as you require.
00027  *
00028  * @Note Synchronization level: Interrupt safe
00029  *
00030  * Example:
00031  * @code
00032  * // Toggle the blinking led after 5 seconds
00033  *
00034  * #include "mbed.h"
00035  *
00036  * Ticker timer;
00037  * DigitalOut led1(LED1);
00038  * DigitalOut led2(LED2);
00039  *
00040  * int flip = 0;
00041  *
00042  * void attime() {
00043  *     flip = !flip;
00044  * }
00045  *
00046  * int main() {
00047  *     timer.attach(&attime, 5);
00048  *     while(1) {
00049  *         if(flip == 0) {
00050  *             led1 = !led1;
00051  *         } else {
00052  *             led2 = !led2;
00053  *         }
00054  *         wait(0.2);
00055  *     }
00056  * }
00057  * @endcode
00058  */
00059 class Ticker : public TimerEvent {
00060 
00061 public:
00062     Ticker() : TimerEvent() {
00063     }
00064 
00065     Ticker(const ticker_data_t *data) : TimerEvent(data) {
00066         data->interface->init();
00067     }
00068 
00069     /** Attach a function to be called by the Ticker, specifiying the interval in seconds
00070      *
00071      *  @param func pointer to the function to be called
00072      *  @param t the time between calls in seconds
00073      */
00074     void attach(Callback<void()> func, float t) {
00075         attach_us(func, t * 1000000.0f);
00076     }
00077 
00078     /** Attach a member function to be called by the Ticker, specifiying the interval in seconds
00079      *
00080      *  @param obj pointer to the object to call the member function on
00081      *  @param method pointer to the member function to be called
00082      *  @param t the time between calls in seconds
00083      */
00084     template<typename T, typename M>
00085     void attach(T *obj, M method, float t) {
00086         attach(Callback<void()>(obj, method), t);
00087     }
00088 
00089     /** Attach a function to be called by the Ticker, specifiying the interval in micro-seconds
00090      *
00091      *  @param fptr pointer to the function to be called
00092      *  @param t the time between calls in micro-seconds
00093      */
00094     void attach_us(Callback<void()> func, timestamp_t t) {
00095         _function.attach(func);
00096         setup(t);
00097     }
00098 
00099     /** Attach a member function to be called by the Ticker, specifiying the interval in micro-seconds
00100      *
00101      *  @param tptr pointer to the object to call the member function on
00102      *  @param mptr pointer to the member function to be called
00103      *  @param t the time between calls in micro-seconds
00104      */
00105     template<typename T, typename M>
00106     void attach_us(T *obj, M method, timestamp_t t) {
00107         attach_us(Callback<void()>(obj, method), t);
00108     }
00109 
00110     virtual ~Ticker() {
00111         detach();
00112     }
00113 
00114     /** Detach the function
00115      */
00116     void detach();
00117 
00118 protected:
00119     void setup(timestamp_t t);
00120     virtual void handler();
00121 
00122 protected:
00123     timestamp_t         _delay;     /**< Time delay (in microseconds) for re-setting the multi-shot callback. */
00124     Callback<void()>    _function;  /**< Callback. */
00125 };
00126 
00127 } // namespace mbed
00128 
00129 #endif