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//*****************************************************************************

//

// systick.c - Driver for the SysTick timer in NVIC.

//

// Copyright (c) 2005,2006 Luminary Micro, Inc.  All rights reserved.

//

// Software License Agreement

//

// Luminary Micro, Inc. (LMI) is supplying this software for use solely and

// exclusively on LMI's Stellaris Family of microcontroller products.

//

// The software is owned by LMI and/or its suppliers, and is protected under

// applicable copyright laws.  All rights are reserved.  Any use in violation

// of the foregoing restrictions may subject the user to criminal sanctions

// under applicable laws, as well as to civil liability for the breach of the

// terms and conditions of this license.

//

// THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED

// OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF

// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.

// LMI SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR

// CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.

//

// This is part of revision 991 of the Stellaris Driver Library.

//

//*****************************************************************************

//*****************************************************************************

//

//! \addtogroup systick_api

//! @{

//

//*****************************************************************************

#include "../hw_ints.h"

#include "../hw_nvic.h"

#include "../hw_types.h"

#include "debug.h"

#include "interrupt.h"

#include "systick.h"

//*****************************************************************************

//

//! Enables the SysTick counter.

//!

//! This will start the SysTick counter.  If an interrupt handler has been

//! registered, it will be called when the SysTick counter rolls over.

//!

//! \return None.

//

//*****************************************************************************

#if defined(GROUP_enable) || defined(BUILD_ALL) || defined(DOXYGEN)

void

SysTickEnable(void)

{

    //

    // Enable SysTick.

    //

    HWREG(NVIC_ST_CTRL) |= NVIC_ST_CTRL_CLK_SRC | NVIC_ST_CTRL_ENABLE;

}

#endif

//*****************************************************************************

//

//! Disables the SysTick counter.

//!

//! This will stop the SysTick counter.  If an interrupt handler has been

//! registered, it will no longer be called until SysTick is restarted.

//!

//! \return None.

//

//*****************************************************************************

#if defined(GROUP_disable) || defined(BUILD_ALL) || defined(DOXYGEN)

void

SysTickDisable(void)

{

    //

    // Disable SysTick.

    //

    HWREG(NVIC_ST_CTRL) &= ~(NVIC_ST_CTRL_ENABLE);

}

#endif

//*****************************************************************************

//

//! Registers an interrupt handler for the SysTick interrupt.

//!

//! \param pfnHandler is a pointer to the function to be called when the

//! SysTick interrupt occurs.

//!

//! This sets the handler to be called when a SysTick interrupt occurs.

//!

//! \sa IntRegister() for important information about registering interrupt

//! handlers.

//!

//! \return None.

//

//*****************************************************************************

#if defined(GROUP_intregister) || defined(BUILD_ALL) || defined(DOXYGEN)

void

SysTickIntRegister(void (*pfnHandler)(void))

{

    //

    // Register the interrupt handler, returning an error if an error occurs.

    //

    IntRegister(FAULT_SYSTICK, pfnHandler);

    //

    // Enable the SysTick interrupt.

    //

    HWREG(NVIC_ST_CTRL) |= NVIC_ST_CTRL_INTEN;

}

#endif

//*****************************************************************************

//

//! Unregisters the interrupt handler for the SysTick interrupt.

//!

//! This function will clear the handler to be called when a SysTick interrupt

//! occurs.

//!

//! \sa IntRegister() for important information about registering interrupt

//! handlers.

//!

//! \return None.

//

//*****************************************************************************

#if defined(GROUP_intunregister) || defined(BUILD_ALL) || defined(DOXYGEN)

void

SysTickIntUnregister(void)

{

    //

    // Disable the SysTick interrupt.

    //

    HWREG(NVIC_ST_CTRL) &= ~(NVIC_ST_CTRL_INTEN);

    //

    // Unregister the interrupt handler.

    //

    IntUnregister(FAULT_SYSTICK);

}

#endif

//*****************************************************************************

//

//! Enables the SysTick interrupt.

//!

//! This function will enable the SysTick interrupt, allowing it to be

//! reflected to the processor.

//!

//! \return None.

//

//*****************************************************************************

#if defined(GROUP_intenable) || defined(BUILD_ALL) || defined(DOXYGEN)

void

SysTickIntEnable(void)

{

    //

    // Enable the SysTick interrupt.

    //

    HWREG(NVIC_ST_CTRL) |= NVIC_ST_CTRL_INTEN;

}

#endif

//*****************************************************************************

//

//! Disables the SysTick interrupt.

//!

//! This function will disable the SysTick interrupt, preventing it from being

//! reflected to the processor.

//!

//! \return None.

//

//*****************************************************************************

#if defined(GROUP_intdisable) || defined(BUILD_ALL) || defined(DOXYGEN)

void

SysTickIntDisable(void)

{

    //

    // Disable the SysTick interrupt.

    //

    HWREG(NVIC_ST_CTRL) &= ~(NVIC_ST_CTRL_INTEN);

}

#endif

//*****************************************************************************

//

//! Sets the period of the SysTick counter.

//!

//! \param ulPeriod is the number of clock ticks in each period of the SysTick

//! counter; must be between 1 and 16,777,216, inclusive.

//!

//! This function sets the rate at which the SysTick counter wraps; this

//! equates to the number of processor clocks between interrupts.

//!

//! \return None.

//

//*****************************************************************************

#if defined(GROUP_periodset) || defined(BUILD_ALL) || defined(DOXYGEN)

void

SysTickPeriodSet(unsigned long ulPeriod)

{

    //

    // Check the arguments.

    //

    ASSERT((ulPeriod > 0) && (ulPeriod <= 16777216));

    //

    // Set the period of the SysTick counter.

    //

    HWREG(NVIC_ST_RELOAD) = ulPeriod - 1;

}

#endif

//*****************************************************************************

//

//! Gets the period of the SysTick counter.

//!

//! This function returns the rate at which the SysTick counter wraps; this

//! equates to the number of processor clocks between interrupts.

//!

//! \return Returns the period of the SysTick counter.

//

//*****************************************************************************

#if defined(GROUP_periodget) || defined(BUILD_ALL) || defined(DOXYGEN)

unsigned long

SysTickPeriodGet(void)

{

    //

    // Return the period of the SysTick counter.

    //

    return(HWREG(NVIC_ST_RELOAD) + 1);

}

#endif

//*****************************************************************************

//

//! Gets the current value of the SysTick counter.

//!

//! This function returns the current value of the SysTick counter; this will

//! be a value between the period - 1 and zero, inclusive.

//!

//! \return Returns the current value of the SysTick counter.

//

//*****************************************************************************

#if defined(GROUP_valueget) || defined(BUILD_ALL) || defined(DOXYGEN)

unsigned long

SysTickValueGet(void)

{

    //

    // Return the current value of the SysTick counter.

    //

    return(HWREG(NVIC_ST_CURRENT));

}

#endif

//*****************************************************************************

//

// Close the Doxygen group.

//! @}

//

//*****************************************************************************