83 lines
2.1 KiB
C
83 lines
2.1 KiB
C
/** @file hal/micro/system-timer.h
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* @brief Header file for system_timer APIs
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*
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*
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* <!--(C) COPYRIGHT 2010 STMicroelectronics. All rights reserved. -->
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*/
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/** @addtogroup system_timer
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* @brief Functions that provide access to the system clock.
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*
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* A single system tick (as returned by ::halCommonGetInt16uMillisecondTick() and
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* ::halCommonGetInt32uMillisecondTick() ) is approximately 1 millisecond.
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*
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* - When used with a 32.768kHz crystal, the system tick is 0.976 milliseconds.
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*
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* - When used with a 3.6864MHz crystal, the system tick is 1.111 milliseconds.
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*
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* A single quarter-second tick (as returned by
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* ::halCommonGetInt16uQuarterSecondTick() ) is approximately 0.25 seconds.
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*
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* The values used by the time support functions will wrap after an interval.
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* The length of the interval depends on the length of the tick and the number
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* of bits in the value. However, there is no issue when comparing time deltas
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* of less than half this interval with a subtraction, if all data types are the
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* same.
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*
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* See system-timer.h for source code.
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*@{
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*/
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#ifndef SYSTEM_TIMER_H_
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#define SYSTEM_TIMER_H_
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/**
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* @brief Initializes the system tick.
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*
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* @return Time to update the async registers after RTC is started (units of 100
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* microseconds).
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*/
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uint16_t halInternalStartSystemTimer(void);
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/**
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* @brief Returns the current system time in system ticks, as a 16-bit
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* value.
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*
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* @return The least significant 16 bits of the current system time, in system
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* ticks.
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*/
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uint16_t halCommonGetInt16uMillisecondTick(void);
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/**
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* @brief Returns the current system time in system ticks, as a 32-bit
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* value.
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*
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* @nostackusage
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*
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* @return The least significant 32 bits of the current system time, in
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* system ticks.
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*/
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uint32_t halCommonGetInt32uMillisecondTick(void);
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/**
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* @brief Returns the current system time in quarter second ticks, as a
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* 16-bit value.
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*
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* @nostackusage
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*
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* @return The least significant 16 bits of the current system time, in system
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* ticks multiplied by 256.
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*/
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uint16_t halCommonGetInt16uQuarterSecondTick(void);
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#endif //SYSTEM_TIMER_H_
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/**@} //END addtogroup
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*/
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