mirror of https://github.com/ARMmbed/mbed-os.git
118 lines
3.7 KiB
C
118 lines
3.7 KiB
C
/**
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*******************************************************************************
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* @file lpticker.c
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* @brief Implementation of a Low Power Ticker functionality based on RTC
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* @internal
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* @author ON Semiconductor
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* $Rev: $
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* $Date: $
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******************************************************************************
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* Copyright 2016 Semiconductor Components Industries LLC (d/b/a “ON Semiconductor”).
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* All rights reserved. This software and/or documentation is licensed by ON Semiconductor
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* under limited terms and conditions. The terms and conditions pertaining to the software
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* and/or documentation are available at http://www.onsemi.com/site/pdf/ONSEMI_T&C.pdf
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* (“ON Semiconductor Standard Terms and Conditions of Sale, Section 8 Software”) and
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* if applicable the software license agreement. Do not use this software and/or
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* documentation unless you have carefully read and you agree to the limited terms and
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* conditions. By using this software and/or documentation, you agree to the limited
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* terms and conditions.
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*
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* THIS SOFTWARE IS PROVIDED "AS IS". NO WARRANTIES, WHETHER EXPRESS, IMPLIED
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* OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
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* ON SEMICONDUCTOR SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL,
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* INCIDENTAL, OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
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* @endinternal
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*
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* @ingroup lpticker
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*
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* @details
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* This is Low Power ticker derived from RTC
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*
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*/
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#include "device.h"
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#if DEVICE_LOWPOWERTIMER
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#include "sleep_api.h"
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#include "cmsis_nvic.h"
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#include "lp_ticker_api.h"
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#include "rtc.h"
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#include "rtc_map.h"
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#include "sleep.h"
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/* Initialize the RTC for low power ticker */
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void lp_ticker_init()
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{
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fRtcInit();
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}
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/* Return the current RTC counter value in us */
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uint32_t lp_ticker_read()
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{
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return (uint32_t)(fRtcRead() & 0xFFFFFFFF); /* TODO Truncating 64 bit value to 32 bit */
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}
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/* Set interrupt for specified time */
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void lp_ticker_set_interrupt(timestamp_t timestamp)
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{
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/* The RTC Match register needs to be Set to the RTC alarm value */
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fRtcSetInterrupt(timestamp);
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}
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/*Return the time that gets cut off when you return just a 32 bit us resolution number */
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uint32_t lp_ticker_get_overflows_counter(void)
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{
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/* To check; do we need an counter in software in RTC to find overflows */
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uint64_t now = fRtcRead();
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uint32_t overflow = (now & 0xFFFFFFFF00000000) >> 32;
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return overflow;
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}
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/* Return the RTC Match counter contents */
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uint32_t lp_ticker_get_compare_match()
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{
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/* read the alarms and convert to us */
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uint16_t sub_second_alarm = RTCREG->SUB_SECOND_ALARM;
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uint32_t second_alarm = RTCREG->SECOND_ALARM;
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uint64_t alarm_us = (uint64_t)((((float)sub_second_alarm / RTC_CLOCK_HZ) * RTC_SEC_TO_US) +
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(second_alarm * RTC_SEC_TO_US));
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/* TODO truncating to 32 bits */
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return (uint32_t)(alarm_us & 0xFFFFFFFF);
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}
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/* sleep until alarm */
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void lp_ticker_sleep_until(uint32_t now, uint32_t time)
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{
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/* Set the interrupt */
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lp_ticker_set_interrupt(time);
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/* Go to sleep */
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sleep_t obj;
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obj.SleepType = SLEEP_TYPE_NONE;
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obj.timeToSleep = time - now;
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mbed_enter_sleep(&obj);
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/* TBD: This is dummy exit for now; once the entered sleep it should be
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removed and sleep exit should happen through interrupt */
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mbed_exit_sleep(&obj);
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}
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/** Disable low power ticker interrupt
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*
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*/
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void lp_ticker_disable_interrupt(void)
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{
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/* TODO : This is an empty implementation for now */
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}
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/** Clear the low power ticker interrupt
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*
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*/
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void lp_ticker_clear_interrupt(void)
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{
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/* TODO : This is an empty implementation for now */
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}
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#endif /* DEVICE_LOWPOWERTIMER */
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