osd-contiki/cpu/avr/hw_timer.c

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/*
* Copyright (c) 2014, Ralf Schlatterbeck Open Source Consulting
* 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.
*/
/**
* \addgroup hardware timer
*
* @{
*/
/**
* \file
* Header file for hardware timer of AVR microcontrollers
* \author
* Ralf Schlatterbeck <rsc@runtux.com>
*/
#include <avr/pgmspace.h>
#include "contiki.h"
#include "rtimer-arch.h"
#include "hw_timer.h"
#ifndef PLAT_TIMER
#define PLAT_TIMER 0xFF /* invalid timer for comparison */
#endif
int8_t hwtimer_ini (uint8_t timer, uint8_t wgm, uint8_t clock, uint16_t maxt)
{
int8_t i;
HWT_CHECK_TIMER (timer);
if (wgm > HWT_WGM_MASK || wgm == HWT_WGM_RESERVED) {
return HWT_ERR_INVALID_WGM;
}
if (clock > HWT_CLOCK_MASK) {
return HWT_ERR_INVALID_CLOCK;
}
/* Turn off clock, no need to disable interrupt */
*HWT_TCCRB (timer) &= ~HWT_CLOCK_MASK;
*HWT_TCCRA (timer) &= ~(HWT_WGM_MASK_LOW << HWT_WGM_SHIFT_LOW);
*HWT_TCCRA (timer) |= ((wgm & HWT_WGM_MASK_LOW) << HWT_WGM_SHIFT_LOW);
*HWT_TCCRB (timer) &= ~(HWT_WGM_MASK_HIGH << HWT_WGM_SHIFT_HIGH);
*HWT_TCCRB (timer) |= ((wgm & HWT_WGM_MASK_HIGH) << HWT_WGM_SHIFT_HIGH);
for (i=0; i<3; i++) {
HWT_SET_COM (timer, i, HWT_COM_NORMAL);
}
if ( wgm == HWT_WGM_PWM_PHASE_FRQ_ICR
|| wgm == HWT_WGM_PWM_PHASE_ICR
|| wgm == HWT_WGM_CTC_ICR
|| wgm == HWT_WGM_PWM_FAST_ICR
)
{
*HWT_ICR (timer) = maxt;
}
if ( wgm == HWT_WGM_CTC_OCRA
|| wgm == HWT_WGM_PWM_PHASE_FRQ_OCRA
|| wgm == HWT_WGM_PWM_PHASE_OCRA
|| wgm == HWT_WGM_PWM_FAST_OCRA
)
{
*HWT_OCRA (timer) = maxt;
}
/* Set clock, finally */
*HWT_TCCRB (timer) |= clock;
return 0;
}
/*
* ex:ts=8:et:sw=2
*/
/** @} */