Functions
void	SysTickEnable (void)

void	SysTickDisable (void)

void	SysTickIntRegister (void(*pfnHandler)(void))

void	SysTickIntUnregister (void)

void	SysTickIntEnable (void)

void	SysTickIntDisable (void)

void	SysTickPeriodSet (uint32_t ui32Period)

uint32_t	SysTickPeriodGet (void)

uint32_t	SysTickValueGet (void)

Detailed Description

Function Documentation

§ SysTickEnable()

void SysTickEnable ( void )

Enables the SysTick counter.

This function starts the SysTick counter. If an interrupt handler has been registered, it is called when the SysTick counter rolls over.

Note: Calling this function causes the SysTick counter to (re)commence counting from its current value. The counter is not automatically reloaded with the period as specified in a previous call to SysTickPeriodSet(). If an immediate reload is required, the NVIC_ST_CURRENT register must be written to force the reload. Any write to this register clears the SysTick counter to 0 and causes a reload with the supplied period on the next clock.

Returns: None.

References HWREG, NVIC_ST_CTRL, NVIC_ST_CTRL_CLK_SRC, and NVIC_ST_CTRL_ENABLE.

§ SysTickDisable()

void SysTickDisable ( void )

Disables the SysTick counter.

This function stops the SysTick counter. If an interrupt handler has been registered, it is not called until SysTick is restarted.

Returns: None.

References HWREG, NVIC_ST_CTRL, and NVIC_ST_CTRL_ENABLE.

§ SysTickIntRegister()

void SysTickIntRegister ( void(*)(void) pfnHandler )

Registers an interrupt handler for the SysTick interrupt.

Parameters

pfnHandler is a pointer to the function to be called when the SysTick interrupt occurs.

This function registers the handler to be called when a SysTick interrupt occurs.

See also: IntRegister() for important information about registering interrupt handlers.

Returns: None.

References FAULT_SYSTICK, HWREG, IntRegister(), NVIC_ST_CTRL, and NVIC_ST_CTRL_INTEN.

§ SysTickIntUnregister()

void SysTickIntUnregister ( void )

Unregisters the interrupt handler for the SysTick interrupt.

This function unregisters the handler to be called when a SysTick interrupt occurs.

See also: IntRegister() for important information about registering interrupt handlers.

Returns: None.

References FAULT_SYSTICK, HWREG, IntUnregister(), NVIC_ST_CTRL, and NVIC_ST_CTRL_INTEN.

§ SysTickIntEnable()

void SysTickIntEnable ( void )

Enables the SysTick interrupt.

This function enables the SysTick interrupt, allowing it to be reflected to the processor.

Note: The SysTick interrupt handler is not required to clear the SysTick interrupt source because it is cleared automatically by the NVIC when the interrupt handler is called.

Returns: None.

References HWREG, NVIC_ST_CTRL, and NVIC_ST_CTRL_INTEN.

§ SysTickIntDisable()

void SysTickIntDisable ( void )

Disables the SysTick interrupt.

This function disables the SysTick interrupt, preventing it from being reflected to the processor.

Returns: None.

References HWREG, NVIC_ST_CTRL, and NVIC_ST_CTRL_INTEN.

§ SysTickPeriodSet()

void SysTickPeriodSet ( uint32_t ui32Period )

Sets the period of the SysTick counter.

Parameters

ui32Period is the number of clock ticks in each period of the SysTick counter and must be between 1 and 16,777,216, inclusive.

This function sets the rate at which the SysTick counter wraps, which equates to the number of processor clocks between interrupts.

Note: Calling this function does not cause the SysTick counter to reload immediately. If an immediate reload is required, the NVIC_ST_CURRENT register must be written. Any write to this register clears the SysTick counter to 0 and causes a reload with the ui32Period supplied here on the next clock after SysTick is enabled.

Returns: None.

References ASSERT, HWREG, and NVIC_ST_RELOAD.

§ SysTickPeriodGet()

uint32_t SysTickPeriodGet ( void )

Gets the period of the SysTick counter.

This function returns the rate at which the SysTick counter wraps, which equates to the number of processor clocks between interrupts.

Returns: Returns the period of the SysTick counter.

References HWREG, and NVIC_ST_RELOAD.

§ SysTickValueGet()

uint32_t SysTickValueGet ( void )

Gets the current value of the SysTick counter.

This function returns the current value of the SysTick counter, which is a value between the period - 1 and zero, inclusive.

Returns: Returns the current value of the SysTick counter.

References HWREG, and NVIC_ST_CURRENT.

Functions