nes-proj/cpu/stm32w108/hal/micro/system-timer.h
2010-10-25 09:03:38 +00:00

85 lines
2.2 KiB
C

/** @file hal/micro/system-timer.h
* @brief Header file for system_timer APIs
*
*
* <!--(C) COPYRIGHT 2010 STMicroelectronics. All rights reserved. -->
*/
/** @addtogroup system_timer
* @brief Functions that provide access to the system clock.
*
* A single system tick (as returned by ::halCommonGetInt16uMillisecondTick() and
* ::halCommonGetInt32uMillisecondTick() ) is approximately 1 millisecond.
*
* - When used with a 32.768kHz crystal, the system tick is 0.976 milliseconds.
*
* - When used with a 3.6864MHz crystal, the system tick is 1.111 milliseconds.
*
* A single quarter-second tick (as returned by
* ::halCommonGetInt16uQuarterSecondTick() ) is approximately 0.25 seconds.
*
* The values used by the time support functions will wrap after an interval.
* The length of the interval depends on the length of the tick and the number
* of bits in the value. However, there is no issue when comparing time deltas
* of less than half this interval with a subtraction, if all data types are the
* same.
*
* See system-timer.h for source code.
*@{
*/
#ifndef __SYSTEM_TIMER_H__
#define __SYSTEM_TIMER_H__
/**
* @brief Initializes the system tick.
*
* @return Time to update the async registers after RTC is started (units of 100
* microseconds).
*/
int16u halInternalStartSystemTimer(void);
/**
* @brief Returns the current system time in system ticks, as a 16-bit
* value.
*
* @return The least significant 16 bits of the current system time, in system
* ticks.
*/
//#pragma pagezero_on // place this function in zero-page memory for xap
int16u halCommonGetInt16uMillisecondTick(void);
//#pragma pagezero_off
/**
* @brief Returns the current system time in system ticks, as a 32-bit
* value.
*
* @nostackusage
*
* @return The least significant 32 bits of the current system time, in
* system ticks.
*/
int32u halCommonGetInt32uMillisecondTick(void);
/**
* @brief Returns the current system time in quarter second ticks, as a
* 16-bit value.
*
* @nostackusage
*
* @return The least significant 16 bits of the current system time, in system
* ticks multiplied by 256.
*/
int16u halCommonGetInt16uQuarterSecondTick(void);
#endif //__SYSTEM_TIMER_H__
/**@} //END addtogroup
*/