89 lines
3.5 KiB
C
89 lines
3.5 KiB
C
/*
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* Copyright (c) 2015, SICS Swedish ICT.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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*/
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#ifndef __TSCH_ADAPTIVE_TIMESYNC_H__
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#define __TSCH_ADAPTIVE_TIMESYNC_H__
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/********** Includes **********/
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#include "contiki.h"
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#include "net/mac/tsch/tsch-private.h"
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/******** Configuration *******/
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/* Use SFD timestamp for synchronization? By default we merely rely on rtimer and busy wait
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* until SFD is high, which we found to provide greater accuracy on JN516x and CC2420.
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* Note: for association, however, we always use SFD timestamp to know the time of arrival
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* of the EB (because we do not busy-wait for the whole scanning process)
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* */
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#ifdef TSCH_CONF_RESYNC_WITH_SFD_TIMESTAMPS
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#define TSCH_RESYNC_WITH_SFD_TIMESTAMPS TSCH_CONF_RESYNC_WITH_SFD_TIMESTAMPS
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#else
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#define TSCH_RESYNC_WITH_SFD_TIMESTAMPS 0
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#endif
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/* If enabled, remove jitter due to measurement errors */
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#ifdef TSCH_CONF_TIMESYNC_REMOVE_JITTER
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#define TSCH_TIMESYNC_REMOVE_JITTER TSCH_CONF_TIMESYNC_REMOVE_JITTER
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#else
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#define TSCH_TIMESYNC_REMOVE_JITTER TSCH_RESYNC_WITH_SFD_TIMESTAMPS
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#endif
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/* The jitter to remove in ticks.
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* This should be the sum of measurement errors on Tx and Rx nodes.
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* */
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#define TSCH_TIMESYNC_MEASUREMENT_ERROR US_TO_RTIMERTICKS(32)
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/* Base drift value.
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* Used to compensate locally know inaccuracies, such as
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* the effect of having a binary 32.768 kHz timer as the TSCH time base. */
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#ifdef TSCH_CONF_BASE_DRIFT_PPM
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#define TSCH_BASE_DRIFT_PPM TSCH_CONF_BASE_DRIFT_PPM
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#else
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#define TSCH_BASE_DRIFT_PPM 0
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#endif
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/* The approximate number of slots per second */
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#define TSCH_SLOTS_PER_SECOND (1000000 / TSCH_DEFAULT_TS_TIMESLOT_LENGTH)
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/***** External Variables *****/
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/* The neighbor last used as our time source */
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extern struct tsch_neighbor *last_timesource_neighbor;
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/********** Functions *********/
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void tsch_timesync_update(struct tsch_neighbor *n, uint16_t time_delta_asn, int32_t drift_correction);
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int32_t tsch_timesync_adaptive_compensate(rtimer_clock_t delta_ticks);
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#endif /* __TSCH_ADAPTIVE_TIMESYNC_H__ */
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