tmk_core/tool/mbed/mbed-sdk/libraries/mbed/api/Timer.h

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #ifndef MBED_TIMER_H
  17 #define MBED_TIMER_H
  18
  19 #include "platform.h"
  20
  21 namespace mbed {
  22
  23 /** A general purpose timer
  24  *
  25  * Example:
  26  * @code
  27  * // Count the time to toggle a LED
  28  *
  29  * #include "mbed.h"
  30  *
  31  * Timer timer;
  32  * DigitalOut led(LED1);
  33  * int begin, end;
  34  *
  35  * int main() {
  36  *     timer.start();
  37  *     begin = timer.read_us();
  38  *     led = !led;
  39  *     end = timer.read_us();
  40  *     printf("Toggle the led takes %d us", end - begin);
  41  * }
  42  * @endcode
  43  */
  44 class Timer {
  45
  46 public:
  47     Timer();
  48
  49     /** Start the timer
  50      */
  51     void start();
  52
  53     /** Stop the timer
  54      */
  55     void stop();
  56
  57     /** Reset the timer to 0.
  58      *
  59      * If it was already counting, it will continue
  60      */
  61     void reset();
  62
  63     /** Get the time passed in seconds
  64      */
  65     float read();
  66
  67     /** Get the time passed in mili-seconds
  68      */
  69     int read_ms();
  70
  71     /** Get the time passed in micro-seconds
  72      */
  73     int read_us();
  74
  75 #ifdef MBED_OPERATORS
  76     operator float();
  77 #endif
  78
  79 protected:
  80     int slicetime();
  81     int _running;          // whether the timer is running
  82     unsigned int _start;   // the start time of the latest slice
  83     int _time;             // any accumulated time from previous slices
  84 };
  85
  86 } // namespace mbed
  87
  88 #endif