447 lines
15 KiB
C
447 lines
15 KiB
C
//*****************************************************************************
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//
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// mpu.c - Driver for the Cortex-M3 memory protection unit (MPU).
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//
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// Copyright (c) 2007-2011 Texas Instruments Incorporated. All rights reserved.
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// Software License Agreement
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//
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// Texas Instruments (TI) is supplying this software for use solely and
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// exclusively on TI's microcontroller products. The software is owned by
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// TI and/or its suppliers, and is protected under applicable copyright
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// laws. You may not combine this software with "viral" open-source
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// software in order to form a larger program.
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//
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// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
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// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
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// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
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// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
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// DAMAGES, FOR ANY REASON WHATSOEVER.
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//
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// This is part of revision 6852 of the Stellaris Peripheral Driver Library.
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//
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//*****************************************************************************
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//*****************************************************************************
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//
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//! \addtogroup mpu_api
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//! @{
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//
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//*****************************************************************************
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#include "inc/hw_ints.h"
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#include "inc/hw_nvic.h"
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#include "inc/hw_types.h"
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#include "driverlib/debug.h"
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#include "driverlib/interrupt.h"
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#include "driverlib/mpu.h"
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//*****************************************************************************
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//
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//! Enables and configures the MPU for use.
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//!
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//! \param ulMPUConfig is the logical OR of the possible configurations.
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//!
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//! This function enables the Cortex-M3 memory protection unit. It also
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//! configures the default behavior when in privileged mode and while
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//! handling a hard fault or NMI. Prior to enabling the MPU, at least one
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//! region must be set by calling MPURegionSet() or else by enabling the
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//! default region for privileged mode by passing the
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//! \b MPU_CONFIG_PRIV_DEFAULT flag to MPUEnable().
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//! Once the MPU is enabled, a memory management fault will be generated
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//! for any memory access violations.
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//!
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//! The \e ulMPUConfig parameter should be the logical OR of any of the
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//! following:
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//!
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//! - \b MPU_CONFIG_PRIV_DEFAULT enables the default memory map when in
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//! privileged mode and when no other regions are defined. If this option
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//! is not enabled, then there must be at least one valid region already
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//! defined when the MPU is enabled.
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//! - \b MPU_CONFIG_HARDFLT_NMI enables the MPU while in a hard fault or NMI
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//! exception handler. If this option is not enabled, then the MPU is
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//! disabled while in one of these exception handlers and the default
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//! memory map is applied.
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//! - \b MPU_CONFIG_NONE chooses none of the above options. In this case,
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//! no default memory map is provided in privileged mode, and the MPU will
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//! not be enabled in the fault handlers.
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//!
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//! \return None.
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//
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//*****************************************************************************
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void
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MPUEnable(unsigned long ulMPUConfig)
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{
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//
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// Check the arguments.
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//
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ASSERT(!(ulMPUConfig & ~(MPU_CONFIG_PRIV_DEFAULT |
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MPU_CONFIG_HARDFLT_NMI)));
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//
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// Set the MPU control bits according to the flags passed by the user,
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// and also set the enable bit.
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//
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HWREG(NVIC_MPU_CTRL) = ulMPUConfig | NVIC_MPU_CTRL_ENABLE;
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}
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//*****************************************************************************
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//
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//! Disables the MPU for use.
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//!
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//! This function disables the Cortex-M3 memory protection unit. When the
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//! MPU is disabled, the default memory map is used and memory management
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//! faults are not generated.
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//!
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//! \return None.
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//
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//*****************************************************************************
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void
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MPUDisable(void)
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{
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//
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// Turn off the MPU enable bit.
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//
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HWREG(NVIC_MPU_CTRL) &= ~NVIC_MPU_CTRL_ENABLE;
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}
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//*****************************************************************************
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//
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//! Gets the count of regions supported by the MPU.
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//!
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//! This function is used to get the number of regions that are supported by
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//! the MPU. This is the total number that are supported, including regions
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//! that are already programmed.
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//!
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//! \return The number of memory protection regions that are available
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//! for programming using MPURegionSet().
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//
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//*****************************************************************************
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unsigned long
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MPURegionCountGet(void)
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{
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//
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// Read the DREGION field of the MPU type register, and mask off
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// the bits of interest to get the count of regions.
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//
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return((HWREG(NVIC_MPU_TYPE) & NVIC_MPU_TYPE_DREGION_M)
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>> NVIC_MPU_TYPE_DREGION_S);
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}
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//*****************************************************************************
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//
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//! Enables a specific region.
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//!
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//! \param ulRegion is the region number to enable.
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//!
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//! This function is used to enable a memory protection region. The region
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//! should already be set up with the MPURegionSet() function. Once enabled,
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//! the memory protection rules of the region will be applied and access
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//! violations will cause a memory management fault.
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//!
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//! \return None.
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//
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//*****************************************************************************
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void
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MPURegionEnable(unsigned long ulRegion)
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{
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//
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// Check the arguments.
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//
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ASSERT(ulRegion < 8);
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//
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// Select the region to modify.
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//
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HWREG(NVIC_MPU_NUMBER) = ulRegion;
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//
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// Modify the enable bit in the region attributes.
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//
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HWREG(NVIC_MPU_ATTR) |= NVIC_MPU_ATTR_ENABLE;
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}
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//*****************************************************************************
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//
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//! Disables a specific region.
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//!
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//! \param ulRegion is the region number to disable.
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//!
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//! This function is used to disable a previously enabled memory protection
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//! region. The region will remain configured if it is not overwritten with
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//! another call to MPURegionSet(), and can be enabled again by calling
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//! MPURegionEnable().
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//!
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//! \return None.
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//
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//*****************************************************************************
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void
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MPURegionDisable(unsigned long ulRegion)
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{
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//
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// Check the arguments.
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//
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ASSERT(ulRegion < 8);
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//
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// Select the region to modify.
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//
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HWREG(NVIC_MPU_NUMBER) = ulRegion;
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//
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// Modify the enable bit in the region attributes.
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//
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HWREG(NVIC_MPU_ATTR) &= ~NVIC_MPU_ATTR_ENABLE;
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}
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//*****************************************************************************
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//
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//! Sets up the access rules for a specific region.
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//!
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//! \param ulRegion is the region number to set up.
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//! \param ulAddr is the base address of the region. It must be aligned
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//! according to the size of the region specified in ulFlags.
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//! \param ulFlags is a set of flags to define the attributes of the region.
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//!
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//! This function sets up the protection rules for a region. The region has
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//! a base address and a set of attributes including the size, which must
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//! be a power of 2. The base address parameter, \e ulAddr, must be aligned
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//! according to the size.
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//!
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//! The \e ulFlags parameter is the logical OR of all of the attributes
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//! of the region. It is a combination of choices for region size,
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//! execute permission, read/write permissions, disabled sub-regions,
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//! and a flag to determine if the region is enabled.
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//!
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//! The size flag determines the size of a region, and must be one of the
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//! following:
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//!
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//! - \b MPU_RGN_SIZE_32B
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//! - \b MPU_RGN_SIZE_64B
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//! - \b MPU_RGN_SIZE_128B
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//! - \b MPU_RGN_SIZE_256B
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//! - \b MPU_RGN_SIZE_512B
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//! - \b MPU_RGN_SIZE_1K
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//! - \b MPU_RGN_SIZE_2K
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//! - \b MPU_RGN_SIZE_4K
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//! - \b MPU_RGN_SIZE_8K
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//! - \b MPU_RGN_SIZE_16K
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//! - \b MPU_RGN_SIZE_32K
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//! - \b MPU_RGN_SIZE_64K
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//! - \b MPU_RGN_SIZE_128K
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//! - \b MPU_RGN_SIZE_256K
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//! - \b MPU_RGN_SIZE_512K
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//! - \b MPU_RGN_SIZE_1M
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//! - \b MPU_RGN_SIZE_2M
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//! - \b MPU_RGN_SIZE_4M
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//! - \b MPU_RGN_SIZE_8M
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//! - \b MPU_RGN_SIZE_16M
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//! - \b MPU_RGN_SIZE_32M
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//! - \b MPU_RGN_SIZE_64M
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//! - \b MPU_RGN_SIZE_128M
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//! - \b MPU_RGN_SIZE_256M
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//! - \b MPU_RGN_SIZE_512M
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//! - \b MPU_RGN_SIZE_1G
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//! - \b MPU_RGN_SIZE_2G
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//! - \b MPU_RGN_SIZE_4G
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//!
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//! The execute permission flag must be one of the following:
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//!
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//! - \b MPU_RGN_PERM_EXEC enables the region for execution of code
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//! - \b MPU_RGN_PERM_NOEXEC disables the region for execution of code
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//!
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//! The read/write access permissions are applied separately for the
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//! privileged and user modes. The read/write access flags must be one
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//! of the following:
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//!
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//! - \b MPU_RGN_PERM_PRV_NO_USR_NO - no access in privileged or user mode
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//! - \b MPU_RGN_PERM_PRV_RW_USR_NO - privileged read/write, user no access
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//! - \b MPU_RGN_PERM_PRV_RW_USR_RO - privileged read/write, user read-only
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//! - \b MPU_RGN_PERM_PRV_RW_USR_RW - privileged read/write, user read/write
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//! - \b MPU_RGN_PERM_PRV_RO_USR_NO - privileged read-only, user no access
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//! - \b MPU_RGN_PERM_PRV_RO_USR_RO - privileged read-only, user read-only
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//!
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//! The region is automatically divided into 8 equally-sized sub-regions by
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//! the MPU. Sub-regions can only be used in regions of size 256 bytes
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//! or larger. Any of these 8 sub-regions can be disabled. This allows
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//! for creation of ``holes'' in a region which can be left open, or overlaid
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//! by another region with different attributes. Any of the 8 sub-regions
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//! can be disabled with a logical OR of any of the following flags:
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//!
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//! - \b MPU_SUB_RGN_DISABLE_0
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//! - \b MPU_SUB_RGN_DISABLE_1
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//! - \b MPU_SUB_RGN_DISABLE_2
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//! - \b MPU_SUB_RGN_DISABLE_3
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//! - \b MPU_SUB_RGN_DISABLE_4
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//! - \b MPU_SUB_RGN_DISABLE_5
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//! - \b MPU_SUB_RGN_DISABLE_6
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//! - \b MPU_SUB_RGN_DISABLE_7
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//!
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//! Finally, the region can be initially enabled or disabled with one of
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//! the following flags:
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//!
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//! - \b MPU_RGN_ENABLE
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//! - \b MPU_RGN_DISABLE
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//!
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//! As an example, to set a region with the following attributes: size of
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//! 32 KB, execution enabled, read-only for both privileged and user, one
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//! sub-region disabled, and initially enabled; the \e ulFlags parameter would
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//! have the following value:
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//!
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//! <code>
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//! (MPU_RG_SIZE_32K | MPU_RGN_PERM_EXEC | MPU_RGN_PERM_PRV_RO_USR_RO |
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//! MPU_SUB_RGN_DISABLE_2 | MPU_RGN_ENABLE)
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//! </code>
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//!
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//! \note This function will write to multiple registers and is not protected
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//! from interrupts. It is possible that an interrupt which accesses a
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//! region may occur while that region is in the process of being changed.
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//! The safest way to handle this is to disable a region before changing it.
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//! Refer to the discussion of this in the API Detailed Description section.
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//!
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//! \return None.
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//
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//*****************************************************************************
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void
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MPURegionSet(unsigned long ulRegion, unsigned long ulAddr,
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unsigned long ulFlags)
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{
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//
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// Check the arguments.
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//
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ASSERT(ulRegion < 8);
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ASSERT((ulAddr & ~0 << (((ulFlags & NVIC_MPU_ATTR_SIZE_M) >> 1) + 1))
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== ulAddr);
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//
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// Program the base address, use the region field to select the
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// region at the same time.
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//
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HWREG(NVIC_MPU_BASE) = ulAddr | ulRegion | NVIC_MPU_BASE_VALID;
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//
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// Program the region attributes. Set the TEX field and the S, C,
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// and B bits to fixed values that are suitable for all Stellaris
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// memory.
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//
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HWREG(NVIC_MPU_ATTR) = (ulFlags & ~(NVIC_MPU_ATTR_TEX_M |
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NVIC_MPU_ATTR_CACHEABLE)) |
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NVIC_MPU_ATTR_SHAREABLE |
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NVIC_MPU_ATTR_BUFFRABLE;
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}
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//*****************************************************************************
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//
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//! Gets the current settings for a specific region.
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//!
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//! \param ulRegion is the region number to get.
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//! \param pulAddr points to storage for the base address of the region.
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//! \param pulFlags points to the attribute flags for the region.
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//!
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//! This function retrieves the configuration of a specific region. The
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//! meanings and format of the parameters is the same as that of the
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//! MPURegionSet() function.
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//!
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//! This function can be used to save the configuration of a region for
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//! later use with the MPURegionSet() function. The region's enable state
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//! will be preserved in the attributes that are saved.
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//!
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//! \return None.
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//
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//*****************************************************************************
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void
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MPURegionGet(unsigned long ulRegion, unsigned long *pulAddr,
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unsigned long *pulFlags)
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{
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//
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// Check the arguments.
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//
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ASSERT(ulRegion < 8);
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ASSERT(pulAddr);
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ASSERT(pulFlags);
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//
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// Select the region to get.
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//
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HWREG(NVIC_MPU_NUMBER) = ulRegion;
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//
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// Read and store the base address for the region.
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//
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*pulAddr = HWREG(NVIC_MPU_BASE);
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//
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// Read and store the region attributes.
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//
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*pulFlags = HWREG(NVIC_MPU_ATTR);
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}
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//*****************************************************************************
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//
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//! Registers an interrupt handler for the memory management fault.
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//!
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//! \param pfnHandler is a pointer to the function to be called when the
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//! memory management fault occurs.
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//!
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//! This sets and enables the handler to be called when the MPU generates
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//! a memory management fault due to a protection region access violation.
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//!
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//! \sa IntRegister() for important information about registering interrupt
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//! handlers.
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//!
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//! \return None.
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//
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//*****************************************************************************
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void
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MPUIntRegister(void (*pfnHandler)(void))
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{
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//
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// Check the arguments.
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//
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ASSERT(pfnHandler);
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//
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// Register the interrupt handler.
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//
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IntRegister(FAULT_MPU, pfnHandler);
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//
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// Enable the memory management fault.
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//
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IntEnable(FAULT_MPU);
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}
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//*****************************************************************************
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//
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//! Unregisters an interrupt handler for the memory management fault.
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//!
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//! This function will disable and clear the handler to be called when a
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//! memory management fault occurs.
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//!
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//! \sa IntRegister() for important information about registering interrupt
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//! handlers.
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//!
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//! \return None.
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//
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//*****************************************************************************
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void
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MPUIntUnregister(void)
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{
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//
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// Disable the interrupt.
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//
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IntDisable(FAULT_MPU);
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//
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// Unregister the interrupt handler.
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//
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IntUnregister(FAULT_MPU);
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}
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//*****************************************************************************
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//
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// Close the Doxygen group.
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//! @}
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//
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//*****************************************************************************
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