mbed_wait_api_rtos.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 
00017 // This implementation of the wait functions will be compiled only
00018 // if the RTOS is present.
00019 #ifdef MBED_CONF_RTOS_PRESENT
00020 
00021 #include "platform/wait_api.h"
00022 #include "hal/us_ticker_api.h"
00023 #include "rtos/rtos.h"
00024 #include "platform/critical.h"
00025 
00026 void wait(float s) {
00027     wait_us(s * 1000000.0f);
00028 }
00029 
00030 void wait_ms(int ms) {
00031     wait_us(ms * 1000);
00032 }
00033 
00034 void wait_us(int us) {
00035     uint32_t start = us_ticker_read();
00036     // Use the RTOS to wait for millisecond delays if possible
00037     int ms = us / 1000;
00038     if ((ms > 0) && core_util_are_interrupts_enabled()) {
00039         Thread::wait((uint32_t)ms);
00040     }
00041     // Use busy waiting for sub-millisecond delays, or for the whole
00042     // interval if interrupts are not enabled
00043     while ((us_ticker_read() - start) < (uint32_t)us);
00044 }
00045 
00046 #endif // #if MBED_CONF_RTOS_PRESENT
00047