nes-proj/os/sys/clock.h

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/*
* Copyright (c) 2004, Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
* Author: Adam Dunkels <adam@sics.se>
*
*/
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/** \addtogroup timers
* @{
*/
/**
* \defgroup clock Clock library
*
* The clock library is the interface between Contiki and the platform
* specific clock functionality. The clock library defines a macro,
* CLOCK_SECOND, to convert seconds into the tick resolution of the platform.
* Typically this is 1-10 milliseconds, e.g. 4*CLOCK_SECOND could be 512.
* A 16 bit counter would thus overflow every 1-10 minutes.
* Platforms use the tick interrupt to maintain a long term count
* of seconds since startup.
*
* Platforms may also implement rtimers for greater time resolution
* and for real-time interrupts, These use a corresponding RTIMER_SECOND.
*
* \note These timers do not necessarily have a common divisor or are phase locked.
* One may be crystal controlled and the other may not. Low power operation
* or sleep will often use one for wake and disable the other, then give
* it a tick correction after wakeup.
*
* \note The clock library need in many cases not be used
* directly. Rather, the \ref timer "timer library", \ref etimer
* "event timers", or \ref rtimer "rtimer library" should be used.
*
* \sa \ref timer "Timer library"
* \sa \ref etimer "Event timers"
* \sa \ref rtimer "Realtime library"
*
* @{
*/
#ifndef CLOCK_H_
#define CLOCK_H_
#include "contiki.h"
/**
* A second, measured in system clock time.
*
* \hideinitializer
*/
#ifdef CLOCK_CONF_SECOND
#define CLOCK_SECOND CLOCK_CONF_SECOND
#else
#define CLOCK_SECOND (clock_time_t)32
#endif
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/**
* Initialize the clock library.
*
* This function initializes the clock library and should be called
* from the main() function of the system.
*
*/
void clock_init(void);
/**
* Get the current clock time.
*
* This function returns the current system clock time.
*
* \return The current clock time, measured in system ticks.
*/
clock_time_t clock_time(void);
/**
* Get the current value of the platform seconds.
*
* This could be the number of seconds since startup, or
* since a standard epoch.
*
* \return The value.
*/
unsigned long clock_seconds(void);
/**
* Set the value of the platform seconds.
* \param sec The value to set.
*
*/
void clock_set_seconds(unsigned long sec);
/**
* Wait for a given number of ticks.
* \param t How many ticks.
*
*/
void clock_wait(clock_time_t t);
/**
* Delay a given number of microseconds.
* \param dt How many microseconds to delay.
*
* \note Interrupts could increase the delay by a variable amount.
*/
void clock_delay_usec(uint16_t dt);
/**
* Deprecated platform-specific routines.
*
*/
int clock_fine_max(void);
unsigned short clock_fine(void);
void clock_delay(unsigned int delay);
#endif /* CLOCK_H_ */
/** @} */
/** @} */