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/critical.h"
00020 
00021 namespace mbed {
00022 
00023 Timer::Timer() : _running(), _start(), _time(), _ticker_data(get_us_ticker_data()) {
00024     reset();
00025 }
00026 
00027 Timer::Timer(const ticker_data_t *data) : _running(), _start(), _time(), _ticker_data(data) {
00028     reset();
00029 }
00030 
00031 void Timer::start() {
00032     core_util_critical_section_enter();
00033     if (!_running) {
00034         _start = ticker_read(_ticker_data);
00035         _running = 1;
00036     }
00037     core_util_critical_section_exit();
00038 }
00039 
00040 void Timer::stop() {
00041     core_util_critical_section_enter();
00042     _time += slicetime();
00043     _running = 0;
00044     core_util_critical_section_exit();
00045 }
00046 
00047 int Timer::read_us() {
00048     core_util_critical_section_enter();
00049     int time = _time + slicetime();
00050     core_util_critical_section_exit();
00051     return time;
00052 }
00053 
00054 float Timer::read() {
00055     return (float)read_us() / 1000000.0f;
00056 }
00057 
00058 int Timer::read_ms() {
00059     return read_us() / 1000;
00060 }
00061 
00062 int Timer::slicetime() {
00063     core_util_critical_section_enter();
00064     int ret = 0;
00065     if (_running) {
00066         ret = ticker_read(_ticker_data) - _start;
00067     }
00068     core_util_critical_section_exit();
00069     return ret;
00070 }
00071 
00072 void Timer::reset() {
00073     core_util_critical_section_enter();
00074     _start = ticker_read(_ticker_data);
00075     _time = 0;
00076     core_util_critical_section_exit();
00077 }
00078 
00079 Timer::operator float() {
00080     return read();
00081 }
00082 
00083 } // namespace mbed