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Arduino/hardware/sam/system/libsam/source/timetick.c
2011-09-06 21:05:41 +02:00

94 lines
1.9 KiB
C

/*
%atmel_license%
*/
/**
* \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 ) ;
}