Timer.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_TIMER_H
00017 #define MBED_TIMER_H
00018 
00019 #include "platform.h"
00020 #include "ticker_api.h"
00021 
00022 namespace mbed {
00023 
00024 /** A general purpose timer
00025  *
00026  * @Note Synchronization level: Interrupt safe
00027  *
00028  * Example:
00029  * @code
00030  * // Count the time to toggle a LED
00031  *
00032  * #include "mbed.h"
00033  *
00034  * Timer timer;
00035  * DigitalOut led(LED1);
00036  * int begin, end;
00037  *
00038  * int main() {
00039  *     timer.start();
00040  *     begin = timer.read_us();
00041  *     led = !led;
00042  *     end = timer.read_us();
00043  *     printf("Toggle the led takes %d us", end - begin);
00044  * }
00045  * @endcode
00046  */
00047 class Timer {
00048 
00049 public:
00050     Timer();
00051     Timer(const ticker_data_t *data);
00052 
00053     /** Start the timer
00054      */
00055     void start();
00056 
00057     /** Stop the timer
00058      */
00059     void stop();
00060 
00061     /** Reset the timer to 0.
00062      *
00063      * If it was already counting, it will continue
00064      */
00065     void reset();
00066 
00067     /** Get the time passed in seconds
00068      */
00069     float read();
00070 
00071     /** Get the time passed in mili-seconds
00072      */
00073     int read_ms();
00074 
00075     /** Get the time passed in micro-seconds
00076      */
00077     int read_us();
00078 
00079     /** An operator shorthand for read()
00080      */
00081     operator float();
00082 
00083 protected:
00084     int slicetime();
00085     int _running;          // whether the timer is running
00086     unsigned int _start;   // the start time of the latest slice
00087     int _time;             // any accumulated time from previous slices
00088     const ticker_data_t *_ticker_data;
00089 };
00090 
00091 } // namespace mbed
00092 
00093 #endif