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Arduino/hardware/arduino/sam/system/libsam/source/timetick.c
2012-04-28 11:49:28 +02:00

119 lines
3.3 KiB
C

/* ----------------------------------------------------------------------------
* SAM Software Package License
* ----------------------------------------------------------------------------
* Copyright (c) 2011, Atmel Corporation
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the disclaimer below.
*
* Atmel's name may not be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
* DISCLAIMED. IN NO EVENT SHALL ATMEL 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.
* ----------------------------------------------------------------------------
*/
/**
* \file
* Implement simple system tick usage.
*/
/*----------------------------------------------------------------------------
* Headers
*----------------------------------------------------------------------------*/
#include "chip.h"
/*----------------------------------------------------------------------------
* Local variables
*----------------------------------------------------------------------------*/
/** Tick Counter united by ms */
static volatile uint32_t _dwTickCount=0 ;
/*----------------------------------------------------------------------------
* Exported Functions
*----------------------------------------------------------------------------*/
/**
* \brief Handler for Sytem Tick interrupt.
*/
extern void TimeTick_Increment( void )
{
_dwTickCount++ ;
}
/**
* \brief Configures the SAM3 SysTick & reset tickCount.
* Systick interrupt handler will generates 1ms interrupt and increase a
* tickCount.
* \param dwNew_MCK Current master clock.
*/
extern uint32_t TimeTick_Configure( uint32_t dwNew_MCK )
{
_dwTickCount = 0 ;
return SysTick_Config( dwNew_MCK/1000 ) ;
}
/**
* \brief Get current Tick Count, in ms.
*/
extern uint32_t GetTickCount( void )
{
return _dwTickCount ;
}
/**
* \brief Sync Wait for several ms
*/
extern void Wait( volatile uint32_t dwMs )
{
uint32_t dwStart ;
uint32_t dwCurrent ;
dwStart = _dwTickCount ;
do
{
dwCurrent = _dwTickCount ;
} while ( dwCurrent - dwStart < dwMs ) ;
}
/**
* \brief Sync Sleep for several ms
*/
extern void Sleep( volatile uint32_t dwMs )
{
uint32_t dwStart ;
uint32_t dwCurrent ;
dwStart = _dwTickCount ;
do
{
dwCurrent = _dwTickCount ;
if ( dwCurrent - dwStart > dwMs )
{
break ;
}
__WFI() ;
} while( 1 ) ;
}