nes-proj/cpu/avr/rtimer-arch.c
2008-10-14 09:44:12 +00:00

140 lines
3.8 KiB
C

/*
* Copyright (c) 2007, 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.
*
* $Id: rtimer-arch.c,v 1.3 2008/10/14 09:44:12 adamdunkels Exp $
*/
/**
* \file
* AVR-specific rtimer code
* Currently only works on ATMEGAs that have Timer 3.
* \author
* Fredrik Osterlind <fros@sics.se>
* Joakim Eriksson <joakime@sics.se>
*/
/* OBS: 8 seconds maximum time! */
#include <avr/io.h>
#include <avr/interrupt.h>
#include "lib/energest.h"
#include "sys/rtimer.h"
#include "rtimer-arch.h"
#if defined(__AVR_ATmega1284P__)
#define ETIMSK TIMSK3
#define ETIFR TIFR3
#define TICIE3 ICIE3
//Has no 'C', so we just set it to B. The code doesn't really use C so this
//is safe to do but lets it compile
#define OCIE3C OCIE3B
#define OCF3C OCF3B
#endif
/*---------------------------------------------------------------------------*/
#ifdef TCNT3
ISR (TIMER3_COMPA_vect) {
ENERGEST_ON(ENERGEST_TYPE_IRQ);
ETIMSK &= ~((1 << OCIE3A) | (1 << OCIE3B) | (1 << TOIE3) |
(1 << TICIE3) | (1 << OCIE3C));
/* Call rtimer callback */
rtimer_run_next();
ENERGEST_OFF(ENERGEST_TYPE_IRQ);
}
#else
#error "No Timer3 in rtimer-arch.c"
#endif
/*---------------------------------------------------------------------------*/
void
rtimer_arch_init(void)
{
/* Disable interrupts (store old state) */
uint8_t sreg;
sreg = SREG;
cli ();
#ifdef TCNT3
ETIMSK &= ~((1 << OCIE3A) | (1 << OCIE3B) | (1 << TOIE3) |
(1 << TICIE3) | (1 << OCIE3C));
ETIFR |= (1 << ICF3) | (1 << OCF3A) | (1 << OCF3B) | (1 << TOV3) |
(1 << OCF3C);
/* Default timer behaviour */
TCCR3A = 0;
TCCR3B = 0;
TCCR3C = 0;
/* Reset counter */
TCNT3 = 0;
/* Maximum prescaler */
TCCR3B |= 5;
#else
#error "No Timer3 in rtimer-arch.c"
#endif
/* Restore interrupt state */
SREG = sreg;
}
/*---------------------------------------------------------------------------*/
void
rtimer_arch_schedule(rtimer_clock_t t)
{
/* Disable interrupts (store old state) */
uint8_t sreg;
sreg = SREG;
cli ();
#ifdef TCNT3
/* Set compare register */
OCR3A = t;
ETIFR |= (1 << ICF3) | (1 << OCF3A) | (1 << OCF3B) | (1 << TOV3) |
(1 << OCF3C);
ETIMSK |= (1 << OCIE3A);
#else
#error "No Timer3 in rtimer-arch.c"
#endif
/* Restore interrupt state */
SREG = sreg;
}