nes-proj/arch/cpu/msp430/f5xxx/clock.c

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/*
* Copyright (c) 2011, 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.
*/
#include "contiki.h"
#include "sys/clock.h"
#include "sys/etimer.h"
#include "rtimer-arch.h"
#include "dev/watchdog.h"
#include "isr_compat.h"
#define INTERVAL (RTIMER_ARCH_SECOND / CLOCK_SECOND)
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#define MAX_TICKS (~((clock_time_t)0) / 2)
#define CLOCK_LT(a, b) ((int16_t)((a)-(b)) < 0)
static volatile unsigned long seconds;
static volatile clock_time_t count = 0;
/* last_tar is used for calculating clock_fine, last_ccr might be better? */
static volatile uint16_t last_tar = 0;
/*---------------------------------------------------------------------------*/
static inline uint16_t
read_tar(void)
{
/* Same as clock_counter(), but can be inlined */
uint16_t t1, t2;
do {
t1 = TA1R;
t2 = TA1R;
} while(t1 != t2);
return t1;
}
/*---------------------------------------------------------------------------*/
ISR(TIMER1_A1, timera1)
{
/* watchdog_start(); */
if(TA1IV == 2) {
/* HW timer bug fix: Interrupt handler called before TR==CCR.
* Occurs when timer state is toggled between STOP and CONT. */
while(TA1CTL & MC1 && TA1CCR1 - TA1R == 1);
last_tar = read_tar();
/* Make sure interrupt time is future */
while(!CLOCK_LT(last_tar, TA1CCR1)) {
TA1CCR1 += INTERVAL;
++count;
/* Make sure the CLOCK_CONF_SECOND is a power of two, to ensure
that the modulo operation below becomes a logical and and not
an expensive divide. Algorithm from Wikipedia:
http://en.wikipedia.org/wiki/Power_of_two */
#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(count % CLOCK_CONF_SECOND == 0) {
++seconds;
}
last_tar = read_tar();
}
if(etimer_pending() &&
(etimer_next_expiration_time() - count - 1) > MAX_TICKS) {
etimer_request_poll();
LPM4_EXIT;
}
}
/* if(process_nevents() >= 0) {
LPM4_EXIT;
}*/
/* watchdog_stop(); */
}
/*---------------------------------------------------------------------------*/
clock_time_t
clock_time(void)
{
clock_time_t t1, t2;
do {
t1 = count;
t2 = count;
} while(t1 != t2);
return t1;
}
/*---------------------------------------------------------------------------*/
void
clock_set(clock_time_t clock, clock_time_t fclock)
{
TA1R = fclock;
TA1CCR1 = fclock + INTERVAL;
count = clock;
}
/*---------------------------------------------------------------------------*/
int
clock_fine_max(void)
{
return INTERVAL;
}
/*---------------------------------------------------------------------------*/
unsigned short
clock_fine(void)
{
unsigned short t;
/* Assign last_tar to local varible that can not be changed by interrupt */
t = last_tar;
/* perform calc based on t, TAR will not be changed during interrupt */
return (unsigned short) (TA1R - t);
}
/*---------------------------------------------------------------------------*/
void
clock_init(void)
{
dint();
/* Select SMCLK (2.4576MHz), clear TAR */
/* TACTL = TASSEL1 | TACLR | ID_3; */
/* Select ACLK 32768Hz clock, divide by 2 */
/* TA1CTL = TASSEL0 | TACLR | ID_1; */
#if INTERVAL==32768/CLOCK_SECOND
TA1CTL = TASSEL0 | TACLR;
#elif INTERVAL==16384/CLOCK_SECOND
TA1CTL = TASSEL0 | TACLR | ID_1;
#else
#error NEED TO UPDATE clock.c to match interval!
#endif
/* Initialize ccr1 to create the X ms interval. */
/* CCR1 interrupt enabled, interrupt occurs when timer equals CCR1. */
TA1CCTL1 = CCIE;
/* Interrupt after X ms. */
TA1CCR1 = INTERVAL;
/* Start Timer_A in continuous mode. */
TA1CTL |= MC1;
count = 0;
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/* Enable interrupts. */
eint();
}
/*---------------------------------------------------------------------------*/
/**
* Delay the CPU for a multiple of 2.83 us.
*/
void
clock_delay(unsigned int i)
{
while(i--) {
_NOP();
}
}
/*---------------------------------------------------------------------------*/
/*
* Wait for a multiple of 10 ms.
*
*/
void
clock_wait(clock_time_t i)
{
clock_time_t start;
start = clock_time();
while(clock_time() - start < (clock_time_t)i);
}
/*---------------------------------------------------------------------------*/
void
clock_set_seconds(unsigned long sec)
{
int s;
s = splhigh();
seconds = sec;
splx(s);
}
/*---------------------------------------------------------------------------*/
unsigned long
clock_seconds(void)
{
unsigned long t1, t2;
do {
t1 = seconds;
t2 = seconds;
} while(t1 != t2);
return t1;
}
/*---------------------------------------------------------------------------*/
rtimer_clock_t
clock_counter(void)
{
rtimer_clock_t t1, t2;
do {
t1 = TA1R;
t2 = TA1R;
} while(t1 != t2);
return t1;
}
/*---------------------------------------------------------------------------*/