nes-proj/cpu/cc253x/dev/clock.c

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/*
* Copyright (c) 2009, 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.
*/
/**
* \file
* Implementation of the clock functions for the cc253x.
* Ported over from the cc243x original.
* \author
* Zach Shelby (zach@sensinode.com) - original (cc243x)
* George Oikonomou - <oikonomou@users.sourceforge.net> - cc2530 port
*/
#include "sfr-bits.h"
#include "sys/clock.h"
#include "sys/etimer.h"
#include "cc253x.h"
#include "sys/energest.h"
/* Sleep timer runs on the 32k RC osc. */
/* One clock tick is 7.8 ms */
#define TICK_VAL (32768/128) /* 256 */
/*---------------------------------------------------------------------------*/
#if CLOCK_CONF_STACK_FRIENDLY
volatile uint8_t sleep_flag;
#endif
/*---------------------------------------------------------------------------*/
/* Do NOT remove the absolute address and do NOT remove the initialiser here */
__xdata __at(0x0000) static unsigned long timer_value = 0;
static volatile CC_AT_DATA clock_time_t count = 0; /* Uptime in ticks */
static volatile CC_AT_DATA clock_time_t seconds = 0; /* Uptime in secs */
/*---------------------------------------------------------------------------*/
/**
* Each iteration is ~1.0xy usec, so this function delays for roughly len usec
*/
void
clock_delay_usec(uint16_t len)
{
DISABLE_INTERRUPTS();
while(len--) {
ASM(nop);
}
ENABLE_INTERRUPTS();
}
/*---------------------------------------------------------------------------*/
/**
* Wait for a multiple of ~8 ms (a tick)
*/
void
clock_wait(clock_time_t i)
{
clock_time_t start;
start = clock_time();
while(clock_time() - start < (clock_time_t)i);
}
/*---------------------------------------------------------------------------*/
CCIF clock_time_t
clock_time(void)
{
return count;
}
/*---------------------------------------------------------------------------*/
CCIF unsigned long
clock_seconds(void)
{
return seconds;
}
/*---------------------------------------------------------------------------*/
/*
* There is some ambiguity between TI cc2530 software examples and information
* in the datasheet.
*
* TI examples appear to be writing to SLEEPCMD, initialising hardware in a
* fashion semi-similar to cc2430
*
* However, the datasheet claims that those bits in SLEEPCMD are reserved
*
* The code here goes by the datasheet (ignore TI examples) and seems to work.
*/
void
clock_init(void)
{
/* Make sure we know where we stand */
CLKCONCMD = CLKCONCMD_OSC32K | CLKCONCMD_OSC;
/* Stay with 32 KHz RC OSC, Chance System Clock to 32 MHz */
CLKCONCMD &= ~CLKCONCMD_OSC;
while(CLKCONSTA & CLKCONCMD_OSC);
/* Tickspeed 500 kHz for timers[1-4] */
CLKCONCMD |= CLKCONCMD_TICKSPD2 | CLKCONCMD_TICKSPD1;
while(CLKCONSTA != CLKCONCMD);
/* Initialize tick value */
timer_value = ST0;
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timer_value += ((unsigned long int)ST1) << 8;
timer_value += ((unsigned long int)ST2) << 16;
timer_value += TICK_VAL;
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ST2 = (unsigned char)(timer_value >> 16);
ST1 = (unsigned char)(timer_value >> 8);
ST0 = (unsigned char)timer_value;
STIE = 1; /* IEN0.STIE interrupt enable */
}
/*---------------------------------------------------------------------------*/
/* avoid referencing bits, we don't call code which use them */
#pragma save
#if CC_CONF_OPTIMIZE_STACK_SIZE
#pragma exclude bits
#endif
void
clock_isr(void) __interrupt(ST_VECTOR)
{
DISABLE_INTERRUPTS();
ENERGEST_ON(ENERGEST_TYPE_IRQ);
/*
* Read value of the ST0:ST1:ST2, add TICK_VAL and write it back.
* Next interrupt occurs after the current time + TICK_VAL
*/
timer_value = ST0;
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timer_value += ((unsigned long int)ST1) << 8;
timer_value += ((unsigned long int)ST2) << 16;
timer_value += TICK_VAL;
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ST2 = (unsigned char)(timer_value >> 16);
ST1 = (unsigned char)(timer_value >> 8);
ST0 = (unsigned char)timer_value;
++count;
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/* 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;
}
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#if CLOCK_CONF_STACK_FRIENDLY
sleep_flag = 1;
#else
if(etimer_pending()
&& (etimer_next_expiration_time() - count - 1) > MAX_TICKS) {
etimer_request_poll();
}
#endif
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STIF = 0; /* IRCON.STIF */
ENERGEST_OFF(ENERGEST_TYPE_IRQ);
ENABLE_INTERRUPTS();
}
#pragma restore
/*---------------------------------------------------------------------------*/