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/******************************************************************************
* The MIT License
*
* Copyright (c) 2010 Perry Hung.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*****************************************************************************/
/**
* @file time.h
* @brief Timing and delay functions.
*/
#ifndef _TIME_H
#define _TIME_H
#ifdef __cplusplus
extern "C"{
#endif
#include "nvic.h"
#include "systick.h"
#include "boards.h"
#define US_PER_MS 1000
extern volatile uint32 systick_timer_millis;
/**
* Returns time (in milliseconds) since the beginning of program
* execution. On overflow, restarts at 0.
* @see micros()
*/
static inline uint32 millis(void) {
return systick_timer_millis;
}
/**
* Returns time (in microseconds) since the beginning of program
* execution. On overflow, restarts at 0.
* @see millis()
*/
static inline uint32 micros(void) {
uint32 ms;
uint32 cycle_cnt;
uint32 res;
nvic_globalirq_disable();
cycle_cnt = systick_get_count();
ms = millis();
nvic_globalirq_enable();
/* MAPLE_RELOAD_VAL is 1 less than the number of cycles it actually
takes to complete a systick reload */
res = (ms * US_PER_MS) +
(MAPLE_RELOAD_VAL + 1 - cycle_cnt)/CYCLES_PER_MICROSECOND;
return res;
}
/**
* Delay for at least the given number of milliseconds.
*
* Interrupts, etc. may cause the actual number of milliseconds to
* exceed ms. However, this function will return no less than ms
* milliseconds from the time it is called.
*
* @param ms the number of milliseconds to delay.
* @see delayMicroseconds()
*/
void delay(unsigned long ms);
/**
* Delay for at least the given number of microseconds.
*
* Interrupts, etc. may cause the actual number of microseconds to
* exceed us. However, this function will return no less than us
* microseconds from the time it is called.
*
* @param us the number of microseconds to delay.
* @see delay()
*/
void delayMicroseconds(uint32 us);
#ifdef __cplusplus
} // extern "C"
#endif
#endif
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