nes-proj/cpu/cc253x/rtimer-arch.c

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/*
* Copyright (c) 2010, Loughborough University - 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
* Hardware-dependent functions used to support the
* contiki rtimer module.
*
* clock_init() has set our tick speed prescaler already, so we
* are ticking with 500 kHz freq.
*
* Contiki typedefs rtimer_clock_t as unsigned short (16bit)
* It thus makes sense to use the 16bit timer (Timer 1)
*
* This file contains an ISR and must reside in the HOME bank
*
* \author
* George Oikonomou - <oikonomou@users.sourceforge.net>
*/
#include "sys/rtimer.h"
#include "sfr-bits.h"
#include "cc253x.h"
#include "sys/energest.h"
#include "debug.h"
#include <stdio.h>
#define RT_MODE_COMPARE() do { T1CCTL1 |= T1CCTL_MODE; } while(0)
#define RT_MODE_CAPTURE() do { T1CCTL1 &= ~T1CCTL_MODE; } while(0)
/*---------------------------------------------------------------------------*/
void
rtimer_arch_init(void)
{
/*
* - Free running mode
* - Prescale by 32:
* Tick Speed has been prescaled to 500 kHz already in clock_init()
* We further prescale by 32 resulting in 15625 Hz for this timer.
*/
T1CTL = (T1CTL_DIV1 | T1CTL_MODE0);
T1STAT = 0;
/* Timer 1, Channel 1. Compare Mode (0x04), Interrupt mask on (0x40) */
T1CCTL1 = T1CCTL_MODE | T1CCTL_IM;
/* Interrupt Mask Flags: No interrupt on overflow */
OVFIM = 0;
/* Acknowledge Timer 1 Interrupts */
T1IE = 1;
}
/*---------------------------------------------------------------------------*/
void
rtimer_arch_schedule(rtimer_clock_t t)
{
/* Switch to capture mode before writing T1CC1x and
* set the compare mode values so we can get an interrupt after t */
RT_MODE_CAPTURE();
T1CC1L = (unsigned char) t;
T1CC1H = (unsigned char) (t >> 8);
RT_MODE_COMPARE();
/* Turn on compare mode interrupt */
T1STAT = 0;
T1CCTL1 |= T1CCTL_IM;
}
/*---------------------------------------------------------------------------*/
/* avoid referencing bits, we don't call code which use them */
#pragma save
#if CC_CONF_OPTIMIZE_STACK_SIZE
#pragma exclude bits
#endif
void
rtimer_isr(void) __interrupt(T1_VECTOR)
{
T1IE = 0; /* Ignore Timer 1 Interrupts */
ENERGEST_ON(ENERGEST_TYPE_IRQ);
/* No more interrupts from Channel 1 till next rtimer_arch_schedule() call */
T1STAT &= ~T1STAT_CH1IF;
T1CCTL1 &= ~T1CCTL_IM;
rtimer_run_next();
ENERGEST_OFF(ENERGEST_TYPE_IRQ);
T1IE = 1; /* Acknowledge Timer 1 Interrupts */
}
#pragma restore