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