Timer.cpp

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 #include "drivers/Timer.h"
00017 #include "hal/ticker_api.h"
00018 #include "hal/us_ticker_api.h"
00019 #include "platform/mbed_critical.h"
00020 #include "hal/lp_ticker_api.h"
00021 
00022 namespace mbed {
00023 
00024 Timer::Timer() : _running(), _start(), _time(), _ticker_data(get_us_ticker_data()), _lock_deepsleep(true)
00025 {
00026     reset();
00027 }
00028 
00029 Timer::Timer(const ticker_data_t *data) : _running(), _start(), _time(), _ticker_data(data), _lock_deepsleep(true)
00030 {
00031     reset();
00032 #if DEVICE_LPTICKER
00033     _lock_deepsleep = (data != get_lp_ticker_data());
00034 #endif
00035 }
00036 
00037 Timer::~Timer()
00038 {
00039     core_util_critical_section_enter();
00040     if (_running) {
00041         if (_lock_deepsleep) {
00042             sleep_manager_unlock_deep_sleep();
00043         }
00044     }
00045     _running = 0;
00046     core_util_critical_section_exit();
00047 }
00048 
00049 void Timer::start()
00050 {
00051     core_util_critical_section_enter();
00052     if (!_running) {
00053         if (_lock_deepsleep) {
00054             sleep_manager_lock_deep_sleep();
00055         }
00056         _start = ticker_read_us(_ticker_data);
00057         _running = 1;
00058     }
00059     core_util_critical_section_exit();
00060 }
00061 
00062 void Timer::stop()
00063 {
00064     core_util_critical_section_enter();
00065     _time += slicetime();
00066     if (_running) {
00067         if (_lock_deepsleep) {
00068             sleep_manager_unlock_deep_sleep();
00069         }
00070     }
00071     _running = 0;
00072     core_util_critical_section_exit();
00073 }
00074 
00075 int Timer::read_us()
00076 {
00077     return read_high_resolution_us();
00078 }
00079 
00080 float Timer::read()
00081 {
00082     return (float)read_high_resolution_us() / 1000000.0f;
00083 }
00084 
00085 int Timer::read_ms()
00086 {
00087     return read_high_resolution_us() / 1000;
00088 }
00089 
00090 us_timestamp_t Timer::read_high_resolution_us()
00091 {
00092     core_util_critical_section_enter();
00093     us_timestamp_t time = _time + slicetime();
00094     core_util_critical_section_exit();
00095     return time;
00096 }
00097 
00098 us_timestamp_t Timer::slicetime()
00099 {
00100     us_timestamp_t ret = 0;
00101     core_util_critical_section_enter();
00102     if (_running) {
00103         ret = ticker_read_us(_ticker_data) - _start;
00104     }
00105     core_util_critical_section_exit();
00106     return ret;
00107 }
00108 
00109 void Timer::reset()
00110 {
00111     core_util_critical_section_enter();
00112     _start = ticker_read_us(_ticker_data);
00113     _time = 0;
00114     core_util_critical_section_exit();
00115 }
00116 
00117 Timer::operator float()
00118 {
00119     return read();
00120 }
00121 
00122 } // namespace mbed