From 44b979ac3dc53b29ee8176517b7d9a10935630c0 Mon Sep 17 00:00:00 2001 From: Yuval Adam Date: Mon, 29 Oct 2012 21:36:23 +0200 Subject: Initial code --- driverlib/systick.c | 275 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 275 insertions(+) create mode 100644 driverlib/systick.c (limited to 'driverlib/systick.c') diff --git a/driverlib/systick.c b/driverlib/systick.c new file mode 100644 index 0000000..d4e7548 --- /dev/null +++ b/driverlib/systick.c @@ -0,0 +1,275 @@ +//***************************************************************************** +// +// systick.c - Driver for the SysTick timer in NVIC. +// +// Copyright (c) 2005-2012 Texas Instruments Incorporated. All rights reserved. +// Software License Agreement +// +// 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 following disclaimer. +// +// Redistributions in binary form must reproduce the above copyright +// notice, this list of conditions and the following disclaimer in the +// documentation and/or other materials provided with the +// distribution. +// +// Neither the name of Texas Instruments Incorporated nor the names of +// its contributors may be used to endorse or promote products derived +// from this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS 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. +// +// This is part of revision 9453 of the Stellaris Peripheral Driver Library. +// +//***************************************************************************** + +//***************************************************************************** +// +//! \addtogroup systick_api +//! @{ +// +//***************************************************************************** + +#include "inc/hw_ints.h" +#include "inc/hw_nvic.h" +#include "inc/hw_types.h" +#include "driverlib/debug.h" +#include "driverlib/interrupt.h" +#include "driverlib/systick.h" + +//***************************************************************************** +// +//! 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 \b 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. +//! +//! \return None. +// +//***************************************************************************** +void +SysTickEnable(void) +{ + // + // Enable SysTick. + // + HWREG(NVIC_ST_CTRL) |= NVIC_ST_CTRL_CLK_SRC | NVIC_ST_CTRL_ENABLE; +} + +//***************************************************************************** +// +//! 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. +//! +//! \return None. +// +//***************************************************************************** +void +SysTickDisable(void) +{ + // + // Disable SysTick. + // + HWREG(NVIC_ST_CTRL) &= ~(NVIC_ST_CTRL_ENABLE); +} + +//***************************************************************************** +// +//! 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 function registers the handler to be called when a SysTick interrupt +//! occurs. +//! +//! \sa IntRegister() for important information about registering interrupt +//! handlers. +//! +//! \return None. +// +//***************************************************************************** +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; +} + +//***************************************************************************** +// +//! Unregisters the interrupt handler for the SysTick interrupt. +//! +//! This function unregisters the handler to be called when a SysTick interrupt +//! occurs. +//! +//! \sa IntRegister() for important information about registering interrupt +//! handlers. +//! +//! \return None. +// +//***************************************************************************** +void +SysTickIntUnregister(void) +{ + // + // Disable the SysTick interrupt. + // + HWREG(NVIC_ST_CTRL) &= ~(NVIC_ST_CTRL_INTEN); + + // + // Unregister the interrupt handler. + // + IntUnregister(FAULT_SYSTICK); +} + +//***************************************************************************** +// +//! 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. +//! +//! \return None. +// +//***************************************************************************** +void +SysTickIntEnable(void) +{ + // + // Enable the SysTick interrupt. + // + HWREG(NVIC_ST_CTRL) |= NVIC_ST_CTRL_INTEN; +} + +//***************************************************************************** +// +//! Disables the SysTick interrupt. +//! +//! This function disables the SysTick interrupt, preventing it from being +//! reflected to the processor. +//! +//! \return None. +// +//***************************************************************************** +void +SysTickIntDisable(void) +{ + // + // Disable the SysTick interrupt. + // + HWREG(NVIC_ST_CTRL) &= ~(NVIC_ST_CTRL_INTEN); +} + +//***************************************************************************** +// +//! Sets the period of the SysTick counter. +//! +//! \param ulPeriod 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 \b NVIC_ST_CURRENT +//! register must be written. Any write to this register clears the SysTick +//! counter to 0 and causes a reload with the \e ulPeriod supplied here on +//! the next clock after SysTick is enabled. +//! +//! \return None. +// +//***************************************************************************** +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; +} + +//***************************************************************************** +// +//! 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. +//! +//! \return Returns the period of the SysTick counter. +// +//***************************************************************************** +unsigned long +SysTickPeriodGet(void) +{ + // + // Return the period of the SysTick counter. + // + return(HWREG(NVIC_ST_RELOAD) + 1); +} + +//***************************************************************************** +// +//! 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. +//! +//! \return Returns the current value of the SysTick counter. +// +//***************************************************************************** +unsigned long +SysTickValueGet(void) +{ + // + // Return the current value of the SysTick counter. + // + return(HWREG(NVIC_ST_CURRENT)); +} + +//***************************************************************************** +// +// Close the Doxygen group. +//! @} +// +//***************************************************************************** -- cgit v1.3.1