nes-proj/cpu/pic32/clock.c

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/*
* Contiki PIC32 Port project
*
* Copyright (c) 2012,
* Scuola Superiore Sant'Anna (http://www.sssup.it) and
* Consorzio Nazionale Interuniversitario per le Telecomunicazioni
* (http://www.cnit.it).
*
* 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.
*
*/
/**
* \addtogroup pic32 PIC32 Contiki Port
*
* @{
*/
/**
* \file clock.c
* \brief Clock routines.
* \author Giovanni Pellerano <giovanni.pellerano@evilaliv3.org>
* \author Daniele Alessandrelli <d.alessandrelli@sssup.it>
* \date 2012-03-21
*/
#include <pic32_clock.h>
#include <pic32_timer.h>
#include <pic32_irq.h>
#include <sys/clock.h>
#include <sys/etimer.h>
#include "contiki.h"
static volatile clock_time_t ticks;
static volatile unsigned long seconds;
/*---------------------------------------------------------------------------*/
static inline void
clock_callback(void)
{
++ticks;
if(etimer_pending()) {
etimer_request_poll();
}
#if (CLOCK_CONF_SECOND & (CLOCK_CONF_SECOND - 1)) != 0
#error CLOCK_CONF_SECOND must be a power of two (i.e., 1, 2, 4, 8, 16, 32, 64, ...).
#error Change CLOCK_CONF_SECOND in contiki-conf.h.
#endif
if((ticks % CLOCK_SECOND) == 0) {
++seconds;
}
}
/*---------------------------------------------------------------------------*/
clock_time_t
clock_time(void)
{
return ticks;
}
/*---------------------------------------------------------------------------*/
unsigned long
clock_seconds(void)
{
return seconds;
}
/*---------------------------------------------------------------------------*/
void
clock_set_seconds(unsigned long sec)
{
seconds = sec;
}
/*---------------------------------------------------------------------------*/
void
clock_init(void)
{
ticks = 0;
seconds = 0;
pic32_timer1_init(CLOCK_SECOND);
pic32_timer1_enable_irq();
pic32_timer1_start();
}
/*---------------------------------------------------------------------------*/
void
clock_delay_usec(uint16_t dt)
{
uint32_t now;
uint32_t stop;
asm volatile("mfc0 %0, $9" : "=r"(now));
/* The Count register is incremented every two system clock (SYSCLK) cycles. */
stop = now + dt * ((pic32_clock_get_system_clock() / 1000000) / 2);
for(;;) {
asm volatile("mfc0 %0, $9" : "=r"(now));
if((int32_t)(now - stop) >= 0) {
break;
}
}
}
/*---------------------------------------------------------------------------*/
/*
* Deprecated platform-specific routines.
*
*/
inline void
clock_delay(unsigned int delay)
{
clock_delay_usec(delay);
}
/*---------------------------------------------------------------------------*/
TIMER_INTERRUPT(1, clock_callback);
/** @} */