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/platform.h"
00020 #include "hal/ticker_api.h"
00021 
00022 namespace mbed {
00023 /** \addtogroup drivers */
00024 
00025 /** A general purpose timer
00026  *
00027  * @note Synchronization level: Interrupt safe
00028  *
00029  * Example:
00030  * @code
00031  * // Count the time to toggle a LED
00032  *
00033  * #include "mbed.h"
00034  *
00035  * Timer timer;
00036  * DigitalOut led(LED1);
00037  * int begin, end;
00038  *
00039  * int main() {
00040  *     timer.start();
00041  *     begin = timer.read_us();
00042  *     led = !led;
00043  *     end = timer.read_us();
00044  *     printf("Toggle the led takes %d us", end - begin);
00045  * }
00046  * @endcode
00047  * @ingroup drivers
00048  */
00049 class Timer {
00050 
00051 public:
00052     Timer();
00053     Timer(const ticker_data_t *data);
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      *  @returns    Time passed in seconds
00072      */
00073     float read();
00074 
00075     /** Get the time passed in milli-seconds
00076      *
00077      *  @returns    Time passed in milli seconds
00078      */
00079     int read_ms();
00080 
00081     /** Get the time passed in micro-seconds
00082      *
00083      *  @returns    Time passed in micro seconds
00084      */
00085     int read_us();
00086 
00087     /** An operator shorthand for read()
00088      */
00089     operator float();
00090 
00091     /** Get in a high resolution type the time passed in micro-seconds.
00092      */
00093     us_timestamp_t read_high_resolution_us();
00094 
00095 protected:
00096     us_timestamp_t slicetime();
00097     int _running;            // whether the timer is running
00098     us_timestamp_t _start;   // the start time of the latest slice
00099     us_timestamp_t _time;    // any accumulated time from previous slices
00100     const ticker_data_t *_ticker_data;
00101 };
00102 
00103 } // namespace mbed
00104 
00105 #endif