Timer.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00020  * SOFTWARE.
00021  */
00022 #ifndef MBED_TIMER_H
00023 #define MBED_TIMER_H
00024 
00025 #include "platform.h"
00026 
00027 namespace mbed {
00028 
00029 /** A general purpose timer
00030  *
00031  * Example:
00032  * @code
00033  * // Count the time to toggle a LED
00034  *
00035  * #include "mbed.h"
00036  *
00037  * Timer timer;
00038  * DigitalOut led(LED1);
00039  * int begin, end;
00040  *
00041  * int main() {
00042  *     timer.start();
00043  *     begin = timer.read_us();
00044  *     led = !led;
00045  *     end = timer.read_us();
00046  *     printf("Toggle the led takes %d us", end - begin);
00047  * }
00048  * @endcode
00049  */
00050 class Timer {
00051 
00052 public:
00053     Timer();
00054 
00055     /** Start the timer
00056      */
00057     void start();
00058 
00059     /** Stop the timer
00060      */
00061     void stop();
00062 
00063     /** Reset the timer to 0.
00064      *
00065      * If it was already counting, it will continue
00066      */
00067     void reset();
00068 
00069     /** Get the time passed in seconds
00070      */
00071     float read();
00072 
00073     /** Get the time passed in mili-seconds
00074      */
00075     int read_ms();
00076 
00077     /** Get the time passed in micro-seconds
00078      */
00079     int read_us();
00080 
00081 #ifdef MBED_OPERATORS
00082     operator float();
00083 #endif
00084 
00085 protected:
00086     int slicetime();
00087     int _running;          // whether the timer is running
00088     unsigned int _start;   // the start time of the latest slice
00089     int _time;             // any accumulated time from previous slices
00090 };
00091 
00092 } // namespace mbed
00093 
00094 #endif
00095