diff options
Diffstat (limited to 'freertos/src/portable/GCC/ARM_CM3/port.c')
| -rw-r--r-- | freertos/src/portable/GCC/ARM_CM3/port.c | 1200 |
1 files changed, 719 insertions, 481 deletions
diff --git a/freertos/src/portable/GCC/ARM_CM3/port.c b/freertos/src/portable/GCC/ARM_CM3/port.c index 34d33d3..dbefc64 100644 --- a/freertos/src/portable/GCC/ARM_CM3/port.c +++ b/freertos/src/portable/GCC/ARM_CM3/port.c @@ -1,481 +1,719 @@ -/* - FreeRTOS V9.0.0 - Copyright (C) 2016 Real Time Engineers Ltd. - All rights reserved - - VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. - - This file is part of the FreeRTOS distribution. - - FreeRTOS is free software; you can redistribute it and/or modify it under - the terms of the GNU General Public License (version 2) as published by the - Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception. - - *************************************************************************** - >>! NOTE: The modification to the GPL is included to allow you to !<< - >>! distribute a combined work that includes FreeRTOS without being !<< - >>! obliged to provide the source code for proprietary components !<< - >>! outside of the FreeRTOS kernel. !<< - *************************************************************************** - - FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY - WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS - FOR A PARTICULAR PURPOSE. Full license text is available on the following - link: http://www.freertos.org/a00114.html - - *************************************************************************** - * * - * FreeRTOS provides completely free yet professionally developed, * - * robust, strictly quality controlled, supported, and cross * - * platform software that is more than just the market leader, it * - * is the industry's de facto standard. * - * * - * Help yourself get started quickly while simultaneously helping * - * to support the FreeRTOS project by purchasing a FreeRTOS * - * tutorial book, reference manual, or both: * - * http://www.FreeRTOS.org/Documentation * - * * - *************************************************************************** - - http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading - the FAQ page "My application does not run, what could be wrong?". Have you - defined configASSERT()? - - http://www.FreeRTOS.org/support - In return for receiving this top quality - embedded software for free we request you assist our global community by - participating in the support forum. - - http://www.FreeRTOS.org/training - Investing in training allows your team to - be as productive as possible as early as possible. Now you can receive - FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers - Ltd, and the world's leading authority on the world's leading RTOS. - - http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products, - including FreeRTOS+Trace - an indispensable productivity tool, a DOS - compatible FAT file system, and our tiny thread aware UDP/IP stack. - - http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate. - Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS. - - http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High - Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS - licenses offer ticketed support, indemnification and commercial middleware. - - http://www.SafeRTOS.com - High Integrity Systems also provide a safety - engineered and independently SIL3 certified version for use in safety and - mission critical applications that require provable dependability. - - 1 tab == 4 spaces! -*/ - -/*----------------------------------------------------------- - * Implementation of functions defined in portable.h for the ARM CM3 port. - *----------------------------------------------------------*/ - -/* Scheduler includes. */ -#include "FreeRTOS.h" -#include "task.h" -#include "fsl_tickless_generic.h" - -extern uint32_t SystemCoreClock; /* in Kinetis SDK, this contains the system core clock speed */ - -/* For backward compatibility, ensure configKERNEL_INTERRUPT_PRIORITY is -defined. The value should also ensure backward compatibility. -FreeRTOS.org versions prior to V4.4.0 did not include this definition. */ -#ifndef configKERNEL_INTERRUPT_PRIORITY - #define configKERNEL_INTERRUPT_PRIORITY 255 -#endif - - - -#define portNVIC_PENDSV_PRI ( ( ( uint32_t ) configKERNEL_INTERRUPT_PRIORITY ) << 16UL ) -#define portNVIC_SYSTICK_PRI ( ( ( uint32_t ) configKERNEL_INTERRUPT_PRIORITY ) << 24UL ) - -/* Constants required to check the validity of an interrupt priority. */ -#define portFIRST_USER_INTERRUPT_NUMBER ( 16 ) -#define portNVIC_IP_REGISTERS_OFFSET_16 ( 0xE000E3F0 ) -#define portAIRCR_REG ( * ( ( volatile uint32_t * ) 0xE000ED0C ) ) -#define portMAX_8_BIT_VALUE ( ( uint8_t ) 0xff ) -#define portTOP_BIT_OF_BYTE ( ( uint8_t ) 0x80 ) -#define portMAX_PRIGROUP_BITS ( ( uint8_t ) 7 ) -#define portPRIORITY_GROUP_MASK ( 0x07UL << 8UL ) -#define portPRIGROUP_SHIFT ( 8UL ) - -/* Masks off all bits but the VECTACTIVE bits in the ICSR register. */ -#define portVECTACTIVE_MASK ( 0xFFUL ) - -/* Constants required to set up the initial stack. */ -#define portINITIAL_XPSR ( 0x01000000UL ) - - - -/* For strict compliance with the Cortex-M spec the task start address should -have bit-0 clear, as it is loaded into the PC on exit from an ISR. */ -#define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL ) - -/* Let the user override the pre-loading of the initial LR with the address of -prvTaskExitError() in case it messes up unwinding of the stack in the -debugger. */ -#ifdef configTASK_RETURN_ADDRESS - #define portTASK_RETURN_ADDRESS configTASK_RETURN_ADDRESS -#else - #define portTASK_RETURN_ADDRESS prvTaskExitError -#endif - -/* Each task maintains its own interrupt status in the critical nesting -variable. */ -static UBaseType_t uxCriticalNesting = 0xaaaaaaaa; - -/* - * Exception handlers. - */ -void xPortPendSVHandler( void ) __attribute__ (( naked )); -void xPortSysTickHandler( void ); -void vPortSVCHandler( void ) __attribute__ (( naked )); - -/* - * Start first task is a separate function so it can be tested in isolation. - */ -static void prvPortStartFirstTask( void ) __attribute__ (( naked )); - -/* - * Used to catch tasks that attempt to return from their implementing function. - */ -static void prvTaskExitError( void ); - -/*-----------------------------------------------------------*/ - -/* - * Used by the portASSERT_IF_INTERRUPT_PRIORITY_INVALID() macro to ensure - * FreeRTOS API functions are not called from interrupts that have been assigned - * a priority above configMAX_SYSCALL_INTERRUPT_PRIORITY. - */ -#if ( configASSERT_DEFINED == 1 ) - static uint8_t ucMaxSysCallPriority = 0; - static uint32_t ulMaxPRIGROUPValue = 0; - static const volatile uint8_t * const pcInterruptPriorityRegisters = ( const volatile uint8_t * const ) portNVIC_IP_REGISTERS_OFFSET_16; -#endif /* configASSERT_DEFINED */ - -/*-----------------------------------------------------------*/ - -/* - * See header file for description. - */ -StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters ) -{ - /* Simulate the stack frame as it would be created by a context switch - interrupt. */ - pxTopOfStack--; /* Offset added to account for the way the MCU uses the stack on entry/exit of interrupts. */ - *pxTopOfStack = portINITIAL_XPSR; /* xPSR */ - pxTopOfStack--; - *pxTopOfStack = ( ( StackType_t ) pxCode ) & portSTART_ADDRESS_MASK; /* PC */ - pxTopOfStack--; - *pxTopOfStack = ( StackType_t ) portTASK_RETURN_ADDRESS; /* LR */ - pxTopOfStack -= 5; /* R12, R3, R2 and R1. */ - *pxTopOfStack = ( StackType_t ) pvParameters; /* R0 */ - pxTopOfStack -= 8; /* R11, R10, R9, R8, R7, R6, R5 and R4. */ - - return pxTopOfStack; -} -/*-----------------------------------------------------------*/ - -static void prvTaskExitError( void ) -{ - /* A function that implements a task must not exit or attempt to return to - its caller as there is nothing to return to. If a task wants to exit it - should instead call vTaskDelete( NULL ). - - Artificially force an assert() to be triggered if configASSERT() is - defined, then stop here so application writers can catch the error. */ - configASSERT( uxCriticalNesting == ~0UL ); - portDISABLE_INTERRUPTS(); - for( ;; ); -} -/*-----------------------------------------------------------*/ - -void vPortSVCHandler( void ) -{ - __asm volatile ( - " ldr r3, pxCurrentTCBConst2 \n" /* Restore the context. */ - " ldr r1, [r3] \n" /* Use pxCurrentTCBConst to get the pxCurrentTCB address. */ - " ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. */ - " ldmia r0!, {r4-r11} \n" /* Pop the registers that are not automatically saved on exception entry and the critical nesting count. */ - " msr psp, r0 \n" /* Restore the task stack pointer. */ - " isb \n" - " mov r0, #0 \n" - " msr basepri, r0 \n" - " orr r14, #0xd \n" - " bx r14 \n" - " \n" - " .align 4 \n" - "pxCurrentTCBConst2: .word pxCurrentTCB \n" - ); -} -/*-----------------------------------------------------------*/ - -static void prvPortStartFirstTask( void ) -{ - __asm volatile( - " ldr r0, =0xE000ED08 \n" /* Use the NVIC offset register to locate the stack. */ - " ldr r0, [r0] \n" - " ldr r0, [r0] \n" - " msr msp, r0 \n" /* Set the msp back to the start of the stack. */ - " cpsie i \n" /* Globally enable interrupts. */ - " cpsie f \n" - " dsb \n" - " isb \n" - " svc 0 \n" /* System call to start first task. */ - " nop \n" - ); -} -/*-----------------------------------------------------------*/ - -/* - * See header file for description. - */ -BaseType_t xPortStartScheduler( void ) -{ - /* configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0. - See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */ - configASSERT( configMAX_SYSCALL_INTERRUPT_PRIORITY ); - - #if( configASSERT_DEFINED == 1 ) - { - volatile uint32_t ulOriginalPriority; - volatile uint8_t * const pucFirstUserPriorityRegister = ( volatile uint8_t * const ) ( portNVIC_IP_REGISTERS_OFFSET_16 + portFIRST_USER_INTERRUPT_NUMBER ); - volatile uint8_t ucMaxPriorityValue; - - /* Determine the maximum priority from which ISR safe FreeRTOS API - functions can be called. ISR safe functions are those that end in - "FromISR". FreeRTOS maintains separate thread and ISR API functions to - ensure interrupt entry is as fast and simple as possible. - - Save the interrupt priority value that is about to be clobbered. */ - ulOriginalPriority = *pucFirstUserPriorityRegister; - - /* Determine the number of priority bits available. First write to all - possible bits. */ - *pucFirstUserPriorityRegister = portMAX_8_BIT_VALUE; - - /* Read the value back to see how many bits stuck. */ - ucMaxPriorityValue = *pucFirstUserPriorityRegister; - - /* Use the same mask on the maximum system call priority. */ - ucMaxSysCallPriority = configMAX_SYSCALL_INTERRUPT_PRIORITY & ucMaxPriorityValue; - - /* Calculate the maximum acceptable priority group value for the number - of bits read back. */ - ulMaxPRIGROUPValue = portMAX_PRIGROUP_BITS; - while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE ) - { - ulMaxPRIGROUPValue--; - ucMaxPriorityValue <<= ( uint8_t ) 0x01; - } - - /* Shift the priority group value back to its position within the AIRCR - register. */ - ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT; - ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK; - - /* Restore the clobbered interrupt priority register to its original - value. */ - *pucFirstUserPriorityRegister = ulOriginalPriority; - } - #endif /* conifgASSERT_DEFINED */ - - /* Make PendSV and SysTick the lowest priority interrupts. */ - portNVIC_SYSPRI2_REG |= portNVIC_PENDSV_PRI; - portNVIC_SYSPRI2_REG |= portNVIC_SYSTICK_PRI; - - /* Start the timer that generates the tick ISR. Interrupts are disabled - here already. */ - vPortSetupTimerInterrupt(); - - /* Initialise the critical nesting count ready for the first task. */ - uxCriticalNesting = 0; - - /* Start the first task. */ - prvPortStartFirstTask(); - - /* Should never get here as the tasks will now be executing! Call the task - exit error function to prevent compiler warnings about a static function - not being called in the case that the application writer overrides this - functionality by defining configTASK_RETURN_ADDRESS. */ - prvTaskExitError(); - - /* Should not get here! */ - return 0; -} -/*-----------------------------------------------------------*/ - -void vPortEndScheduler( void ) -{ - /* Not implemented in ports where there is nothing to return to. - Artificially force an assert. */ - configASSERT( uxCriticalNesting == 1000UL ); -} -/*-----------------------------------------------------------*/ - -void vPortEnterCritical( void ) -{ - portDISABLE_INTERRUPTS(); - uxCriticalNesting++; - - /* This is not the interrupt safe version of the enter critical function so - assert() if it is being called from an interrupt context. Only API - functions that end in "FromISR" can be used in an interrupt. Only assert if - the critical nesting count is 1 to protect against recursive calls if the - assert function also uses a critical section. */ - if( uxCriticalNesting == 1 ) - { - configASSERT( ( portNVIC_INT_CTRL_REG & portVECTACTIVE_MASK ) == 0 ); - } -} -/*-----------------------------------------------------------*/ - -void vPortExitCritical( void ) -{ - configASSERT( uxCriticalNesting ); - uxCriticalNesting--; - if( uxCriticalNesting == 0 ) - { - portENABLE_INTERRUPTS(); - } -} -/*-----------------------------------------------------------*/ - -void xPortPendSVHandler( void ) -{ - /* This is a naked function. */ - - __asm volatile - ( - " mrs r0, psp \n" - " isb \n" - " \n" - " ldr r3, pxCurrentTCBConst \n" /* Get the location of the current TCB. */ - " ldr r2, [r3] \n" - " \n" - " stmdb r0!, {r4-r11} \n" /* Save the remaining registers. */ - " str r0, [r2] \n" /* Save the new top of stack into the first member of the TCB. */ - " \n" - " stmdb sp!, {r3, r14} \n" - " mov r0, %0 \n" - " msr basepri, r0 \n" - " bl vTaskSwitchContext \n" - " mov r0, #0 \n" - " msr basepri, r0 \n" - " ldmia sp!, {r3, r14} \n" - " \n" /* Restore the context, including the critical nesting count. */ - " ldr r1, [r3] \n" - " ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. */ - " ldmia r0!, {r4-r11} \n" /* Pop the registers. */ - " msr psp, r0 \n" - " isb \n" - " bx r14 \n" - " \n" - " .align 4 \n" - "pxCurrentTCBConst: .word pxCurrentTCB \n" - ::"i"(configMAX_SYSCALL_INTERRUPT_PRIORITY) - ); -} -/*-----------------------------------------------------------*/ - -void xPortSysTickHandler( void ) -{ - /* The SysTick runs at the lowest interrupt priority, so when this interrupt - executes all interrupts must be unmasked. There is therefore no need to - save and then restore the interrupt mask value as its value is already - known. */ - portDISABLE_INTERRUPTS(); - { - /* Increment the RTOS tick. */ - if( xTaskIncrementTick() != pdFALSE ) - { - /* A context switch is required. Context switching is performed in - the PendSV interrupt. Pend the PendSV interrupt. */ - portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT; - } - } - portENABLE_INTERRUPTS(); -} - -#if( configASSERT_DEFINED == 1 ) - - void vPortValidateInterruptPriority( void ) - { - uint32_t ulCurrentInterrupt; - uint8_t ucCurrentPriority; - - /* Obtain the number of the currently executing interrupt. */ - __asm volatile( "mrs %0, ipsr" : "=r"( ulCurrentInterrupt ) ); - - /* Is the interrupt number a user defined interrupt? */ - if( ulCurrentInterrupt >= portFIRST_USER_INTERRUPT_NUMBER ) - { - /* Look up the interrupt's priority. */ - ucCurrentPriority = pcInterruptPriorityRegisters[ ulCurrentInterrupt ]; - - /* The following assertion will fail if a service routine (ISR) for - an interrupt that has been assigned a priority above - configMAX_SYSCALL_INTERRUPT_PRIORITY calls an ISR safe FreeRTOS API - function. ISR safe FreeRTOS API functions must *only* be called - from interrupts that have been assigned a priority at or below - configMAX_SYSCALL_INTERRUPT_PRIORITY. - - Numerically low interrupt priority numbers represent logically high - interrupt priorities, therefore the priority of the interrupt must - be set to a value equal to or numerically *higher* than - configMAX_SYSCALL_INTERRUPT_PRIORITY. - - Interrupts that use the FreeRTOS API must not be left at their - default priority of zero as that is the highest possible priority, - which is guaranteed to be above configMAX_SYSCALL_INTERRUPT_PRIORITY, - and therefore also guaranteed to be invalid. - - FreeRTOS maintains separate thread and ISR API functions to ensure - interrupt entry is as fast and simple as possible. - - The following links provide detailed information: - http://www.freertos.org/RTOS-Cortex-M3-M4.html - http://www.freertos.org/FAQHelp.html */ - configASSERT( ucCurrentPriority >= ucMaxSysCallPriority ); - } - - /* Priority grouping: The interrupt controller (NVIC) allows the bits - that define each interrupt's priority to be split between bits that - define the interrupt's pre-emption priority bits and bits that define - the interrupt's sub-priority. For simplicity all bits must be defined - to be pre-emption priority bits. The following assertion will fail if - this is not the case (if some bits represent a sub-priority). - - If the application only uses CMSIS libraries for interrupt - configuration then the correct setting can be achieved on all Cortex-M - devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the - scheduler. Note however that some vendor specific peripheral libraries - assume a non-zero priority group setting, in which cases using a value - of zero will result in unpredicable behaviour. */ - configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue ); - } - -#endif /* configASSERT_DEFINED */ - - - - - - - - - - - - - - - - - - - - - +/*
+ * FreeRTOS Kernel V10.1.1
+ * Copyright (C) 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * http://www.FreeRTOS.org
+ * http://aws.amazon.com/freertos
+ *
+ * 1 tab == 4 spaces!
+ */
+
+/*-----------------------------------------------------------
+ * Implementation of functions defined in portable.h for the ARM CM3 port.
+ *----------------------------------------------------------*/
+
+/* Scheduler includes. */
+#include "FreeRTOS.h"
+#include "task.h"
+
+extern uint32_t SystemCoreClock; /* in Kinetis SDK, this contains the system core clock speed */
+
+/* For backward compatibility, ensure configKERNEL_INTERRUPT_PRIORITY is
+defined. The value should also ensure backward compatibility.
+FreeRTOS.org versions prior to V4.4.0 did not include this definition. */
+#ifndef configKERNEL_INTERRUPT_PRIORITY
+ #define configKERNEL_INTERRUPT_PRIORITY 255
+#endif
+
+#ifndef configSYSTICK_CLOCK_HZ
+ #define configSYSTICK_CLOCK_HZ configCPU_CLOCK_HZ
+ /* Ensure the SysTick is clocked at the same frequency as the core. */
+ #define portNVIC_SYSTICK_CLK_BIT ( 1UL << 2UL )
+#else
+ /* The way the SysTick is clocked is not modified in case it is not the same
+ as the core. */
+ #define portNVIC_SYSTICK_CLK_BIT ( 0 )
+#endif
+
+/* Constants required to manipulate the core. Registers first... */
+#define portNVIC_SYSTICK_CTRL_REG ( * ( ( volatile uint32_t * ) 0xe000e010 ) )
+#define portNVIC_SYSTICK_LOAD_REG ( * ( ( volatile uint32_t * ) 0xe000e014 ) )
+#define portNVIC_SYSTICK_CURRENT_VALUE_REG ( * ( ( volatile uint32_t * ) 0xe000e018 ) )
+#define portNVIC_SYSPRI2_REG ( * ( ( volatile uint32_t * ) 0xe000ed20 ) )
+/* ...then bits in the registers. */
+#define portNVIC_SYSTICK_INT_BIT ( 1UL << 1UL )
+#define portNVIC_SYSTICK_ENABLE_BIT ( 1UL << 0UL )
+#define portNVIC_SYSTICK_COUNT_FLAG_BIT ( 1UL << 16UL )
+#define portNVIC_PENDSVCLEAR_BIT ( 1UL << 27UL )
+#define portNVIC_PEND_SYSTICK_CLEAR_BIT ( 1UL << 25UL )
+
+#define portNVIC_PENDSV_PRI ( ( ( uint32_t ) configKERNEL_INTERRUPT_PRIORITY ) << 16UL )
+#define portNVIC_SYSTICK_PRI ( ( ( uint32_t ) configKERNEL_INTERRUPT_PRIORITY ) << 24UL )
+
+/* Constants required to check the validity of an interrupt priority. */
+#define portFIRST_USER_INTERRUPT_NUMBER ( 16 )
+#define portNVIC_IP_REGISTERS_OFFSET_16 ( 0xE000E3F0 )
+#define portAIRCR_REG ( * ( ( volatile uint32_t * ) 0xE000ED0C ) )
+#define portMAX_8_BIT_VALUE ( ( uint8_t ) 0xff )
+#define portTOP_BIT_OF_BYTE ( ( uint8_t ) 0x80 )
+#define portMAX_PRIGROUP_BITS ( ( uint8_t ) 7 )
+#define portPRIORITY_GROUP_MASK ( 0x07UL << 8UL )
+#define portPRIGROUP_SHIFT ( 8UL )
+
+/* Masks off all bits but the VECTACTIVE bits in the ICSR register. */
+#define portVECTACTIVE_MASK ( 0xFFUL )
+
+/* Constants required to set up the initial stack. */
+#define portINITIAL_XPSR ( 0x01000000UL )
+
+/* The systick is a 24-bit counter. */
+#define portMAX_24_BIT_NUMBER ( 0xffffffUL )
+
+/* A fiddle factor to estimate the number of SysTick counts that would have
+occurred while the SysTick counter is stopped during tickless idle
+calculations. */
+#define portMISSED_COUNTS_FACTOR ( 45UL )
+
+/* For strict compliance with the Cortex-M spec the task start address should
+have bit-0 clear, as it is loaded into the PC on exit from an ISR. */
+#define portSTART_ADDRESS_MASK ( ( StackType_t ) 0xfffffffeUL )
+
+/* Let the user override the pre-loading of the initial LR with the address of
+prvTaskExitError() in case it messes up unwinding of the stack in the
+debugger. */
+#ifdef configTASK_RETURN_ADDRESS
+ #define portTASK_RETURN_ADDRESS configTASK_RETURN_ADDRESS
+#else
+ #define portTASK_RETURN_ADDRESS prvTaskExitError
+#endif
+
+/*
+ * Setup the timer to generate the tick interrupts. The implementation in this
+ * file is weak to allow application writers to change the timer used to
+ * generate the tick interrupt.
+ */
+void vPortSetupTimerInterrupt( void );
+
+/*
+ * Exception handlers.
+ */
+void xPortPendSVHandler( void ) __attribute__ (( naked ));
+void xPortSysTickHandler( void );
+void vPortSVCHandler( void ) __attribute__ (( naked ));
+
+/*
+ * Start first task is a separate function so it can be tested in isolation.
+ */
+static void prvPortStartFirstTask( void ) __attribute__ (( naked ));
+
+/*
+ * Used to catch tasks that attempt to return from their implementing function.
+ */
+static void prvTaskExitError( void );
+
+/*-----------------------------------------------------------*/
+
+/* Each task maintains its own interrupt status in the critical nesting
+variable. */
+static UBaseType_t uxCriticalNesting = 0xaaaaaaaa;
+
+/*
+ * The number of SysTick increments that make up one tick period.
+ */
+#if( configUSE_TICKLESS_IDLE == 1 )
+ static uint32_t ulTimerCountsForOneTick = 0;
+#endif /* configUSE_TICKLESS_IDLE */
+
+/*
+ * The maximum number of tick periods that can be suppressed is limited by the
+ * 24 bit resolution of the SysTick timer.
+ */
+#if( configUSE_TICKLESS_IDLE == 1 )
+ static uint32_t xMaximumPossibleSuppressedTicks = 0;
+#endif /* configUSE_TICKLESS_IDLE */
+
+/*
+ * Compensate for the CPU cycles that pass while the SysTick is stopped (low
+ * power functionality only.
+ */
+#if( configUSE_TICKLESS_IDLE == 1 )
+ static uint32_t ulStoppedTimerCompensation = 0;
+#endif /* configUSE_TICKLESS_IDLE */
+
+/*
+ * Used by the portASSERT_IF_INTERRUPT_PRIORITY_INVALID() macro to ensure
+ * FreeRTOS API functions are not called from interrupts that have been assigned
+ * a priority above configMAX_SYSCALL_INTERRUPT_PRIORITY.
+ */
+#if( configASSERT_DEFINED == 1 )
+ static uint8_t ucMaxSysCallPriority = 0;
+ static uint32_t ulMaxPRIGROUPValue = 0;
+ static const volatile uint8_t * const pcInterruptPriorityRegisters = ( const volatile uint8_t * const ) portNVIC_IP_REGISTERS_OFFSET_16;
+#endif /* configASSERT_DEFINED */
+
+/*-----------------------------------------------------------*/
+
+/*
+ * See header file for description.
+ */
+StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
+{
+ /* Simulate the stack frame as it would be created by a context switch
+ interrupt. */
+ pxTopOfStack--; /* Offset added to account for the way the MCU uses the stack on entry/exit of interrupts. */
+ *pxTopOfStack = portINITIAL_XPSR; /* xPSR */
+ pxTopOfStack--;
+ *pxTopOfStack = ( ( StackType_t ) pxCode ) & portSTART_ADDRESS_MASK; /* PC */
+ pxTopOfStack--;
+ *pxTopOfStack = ( StackType_t ) portTASK_RETURN_ADDRESS; /* LR */
+ pxTopOfStack -= 5; /* R12, R3, R2 and R1. */
+ *pxTopOfStack = ( StackType_t ) pvParameters; /* R0 */
+ pxTopOfStack -= 8; /* R11, R10, R9, R8, R7, R6, R5 and R4. */
+
+ return pxTopOfStack;
+}
+/*-----------------------------------------------------------*/
+
+static void prvTaskExitError( void )
+{
+volatile uint32_t ulDummy = 0UL;
+
+ /* A function that implements a task must not exit or attempt to return to
+ its caller as there is nothing to return to. If a task wants to exit it
+ should instead call vTaskDelete( NULL ).
+
+ Artificially force an assert() to be triggered if configASSERT() is
+ defined, then stop here so application writers can catch the error. */
+ configASSERT( uxCriticalNesting == ~0UL );
+ portDISABLE_INTERRUPTS();
+ while( ulDummy == 0 )
+ {
+ /* This file calls prvTaskExitError() after the scheduler has been
+ started to remove a compiler warning about the function being defined
+ but never called. ulDummy is used purely to quieten other warnings
+ about code appearing after this function is called - making ulDummy
+ volatile makes the compiler think the function could return and
+ therefore not output an 'unreachable code' warning for code that appears
+ after it. */
+ }
+}
+/*-----------------------------------------------------------*/
+
+void vPortSVCHandler( void )
+{
+ __asm volatile (
+ " ldr r3, pxCurrentTCBConst2 \n" /* Restore the context. */
+ " ldr r1, [r3] \n" /* Use pxCurrentTCBConst to get the pxCurrentTCB address. */
+ " ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. */
+ " ldmia r0!, {r4-r11} \n" /* Pop the registers that are not automatically saved on exception entry and the critical nesting count. */
+ " msr psp, r0 \n" /* Restore the task stack pointer. */
+ " isb \n"
+ " mov r0, #0 \n"
+ " msr basepri, r0 \n"
+ " orr r14, #0xd \n"
+ " bx r14 \n"
+ " \n"
+ " .align 4 \n"
+ "pxCurrentTCBConst2: .word pxCurrentTCB \n"
+ );
+}
+/*-----------------------------------------------------------*/
+
+static void prvPortStartFirstTask( void )
+{
+ __asm volatile(
+ " ldr r0, =0xE000ED08 \n" /* Use the NVIC offset register to locate the stack. */
+ " ldr r0, [r0] \n"
+ " ldr r0, [r0] \n"
+ " msr msp, r0 \n" /* Set the msp back to the start of the stack. */
+ " cpsie i \n" /* Globally enable interrupts. */
+ " cpsie f \n"
+ " dsb \n"
+ " isb \n"
+ " svc 0 \n" /* System call to start first task. */
+ " nop \n"
+ );
+}
+/*-----------------------------------------------------------*/
+
+/*
+ * See header file for description.
+ */
+BaseType_t xPortStartScheduler( void )
+{
+ /* configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to 0.
+ See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html */
+ configASSERT( configMAX_SYSCALL_INTERRUPT_PRIORITY );
+
+ #if( configASSERT_DEFINED == 1 )
+ {
+ volatile uint32_t ulOriginalPriority;
+ volatile uint8_t * const pucFirstUserPriorityRegister = ( volatile uint8_t * const ) ( portNVIC_IP_REGISTERS_OFFSET_16 + portFIRST_USER_INTERRUPT_NUMBER );
+ volatile uint8_t ucMaxPriorityValue;
+
+ /* Determine the maximum priority from which ISR safe FreeRTOS API
+ functions can be called. ISR safe functions are those that end in
+ "FromISR". FreeRTOS maintains separate thread and ISR API functions to
+ ensure interrupt entry is as fast and simple as possible.
+
+ Save the interrupt priority value that is about to be clobbered. */
+ ulOriginalPriority = *pucFirstUserPriorityRegister;
+
+ /* Determine the number of priority bits available. First write to all
+ possible bits. */
+ *pucFirstUserPriorityRegister = portMAX_8_BIT_VALUE;
+
+ /* Read the value back to see how many bits stuck. */
+ ucMaxPriorityValue = *pucFirstUserPriorityRegister;
+
+ /* Use the same mask on the maximum system call priority. */
+ ucMaxSysCallPriority = configMAX_SYSCALL_INTERRUPT_PRIORITY & ucMaxPriorityValue;
+
+ /* Calculate the maximum acceptable priority group value for the number
+ of bits read back. */
+ ulMaxPRIGROUPValue = portMAX_PRIGROUP_BITS;
+ while( ( ucMaxPriorityValue & portTOP_BIT_OF_BYTE ) == portTOP_BIT_OF_BYTE )
+ {
+ ulMaxPRIGROUPValue--;
+ ucMaxPriorityValue <<= ( uint8_t ) 0x01;
+ }
+
+ #ifdef __NVIC_PRIO_BITS
+ {
+ /* Check the CMSIS configuration that defines the number of
+ priority bits matches the number of priority bits actually queried
+ from the hardware. */
+ configASSERT( ( portMAX_PRIGROUP_BITS - ulMaxPRIGROUPValue ) == __NVIC_PRIO_BITS );
+ }
+ #endif
+
+ #ifdef configPRIO_BITS
+ {
+ /* Check the FreeRTOS configuration that defines the number of
+ priority bits matches the number of priority bits actually queried
+ from the hardware. */
+ configASSERT( ( portMAX_PRIGROUP_BITS - ulMaxPRIGROUPValue ) == configPRIO_BITS );
+ }
+ #endif
+
+ /* Shift the priority group value back to its position within the AIRCR
+ register. */
+ ulMaxPRIGROUPValue <<= portPRIGROUP_SHIFT;
+ ulMaxPRIGROUPValue &= portPRIORITY_GROUP_MASK;
+
+ /* Restore the clobbered interrupt priority register to its original
+ value. */
+ *pucFirstUserPriorityRegister = ulOriginalPriority;
+ }
+ #endif /* conifgASSERT_DEFINED */
+
+ /* Make PendSV and SysTick the lowest priority interrupts. */
+ portNVIC_SYSPRI2_REG |= portNVIC_PENDSV_PRI;
+ portNVIC_SYSPRI2_REG |= portNVIC_SYSTICK_PRI;
+
+ /* Start the timer that generates the tick ISR. Interrupts are disabled
+ here already. */
+ vPortSetupTimerInterrupt();
+
+ /* Initialise the critical nesting count ready for the first task. */
+ uxCriticalNesting = 0;
+
+ /* Start the first task. */
+ prvPortStartFirstTask();
+
+ /* Should never get here as the tasks will now be executing! Call the task
+ exit error function to prevent compiler warnings about a static function
+ not being called in the case that the application writer overrides this
+ functionality by defining configTASK_RETURN_ADDRESS. Call
+ vTaskSwitchContext() so link time optimisation does not remove the
+ symbol. */
+ vTaskSwitchContext();
+ prvTaskExitError();
+
+ /* Should not get here! */
+ return 0;
+}
+/*-----------------------------------------------------------*/
+
+void vPortEndScheduler( void )
+{
+ /* Not implemented in ports where there is nothing to return to.
+ Artificially force an assert. */
+ configASSERT( uxCriticalNesting == 1000UL );
+}
+/*-----------------------------------------------------------*/
+
+void vPortEnterCritical( void )
+{
+ portDISABLE_INTERRUPTS();
+ uxCriticalNesting++;
+
+ /* This is not the interrupt safe version of the enter critical function so
+ assert() if it is being called from an interrupt context. Only API
+ functions that end in "FromISR" can be used in an interrupt. Only assert if
+ the critical nesting count is 1 to protect against recursive calls if the
+ assert function also uses a critical section. */
+ if( uxCriticalNesting == 1 )
+ {
+ configASSERT( ( portNVIC_INT_CTRL_REG & portVECTACTIVE_MASK ) == 0 );
+ }
+}
+/*-----------------------------------------------------------*/
+
+void vPortExitCritical( void )
+{
+ configASSERT( uxCriticalNesting );
+ uxCriticalNesting--;
+ if( uxCriticalNesting == 0 )
+ {
+ portENABLE_INTERRUPTS();
+ }
+}
+/*-----------------------------------------------------------*/
+
+void xPortPendSVHandler( void )
+{
+ /* This is a naked function. */
+
+ __asm volatile
+ (
+ " mrs r0, psp \n"
+ " isb \n"
+ " \n"
+ " ldr r3, pxCurrentTCBConst \n" /* Get the location of the current TCB. */
+ " ldr r2, [r3] \n"
+ " \n"
+ " stmdb r0!, {r4-r11} \n" /* Save the remaining registers. */
+ " str r0, [r2] \n" /* Save the new top of stack into the first member of the TCB. */
+ " \n"
+ " stmdb sp!, {r3, r14} \n"
+ " mov r0, %0 \n"
+ " msr basepri, r0 \n"
+ " bl vTaskSwitchContext \n"
+ " mov r0, #0 \n"
+ " msr basepri, r0 \n"
+ " ldmia sp!, {r3, r14} \n"
+ " \n" /* Restore the context, including the critical nesting count. */
+ " ldr r1, [r3] \n"
+ " ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. */
+ " ldmia r0!, {r4-r11} \n" /* Pop the registers. */
+ " msr psp, r0 \n"
+ " isb \n"
+ " bx r14 \n"
+ " \n"
+ " .align 4 \n"
+ "pxCurrentTCBConst: .word pxCurrentTCB \n"
+ ::"i"(configMAX_SYSCALL_INTERRUPT_PRIORITY)
+ );
+}
+/*-----------------------------------------------------------*/
+
+void xPortSysTickHandler( void )
+{
+ /* The SysTick runs at the lowest interrupt priority, so when this interrupt
+ executes all interrupts must be unmasked. There is therefore no need to
+ save and then restore the interrupt mask value as its value is already
+ known. */
+ portDISABLE_INTERRUPTS();
+ {
+ /* Increment the RTOS tick. */
+ if( xTaskIncrementTick() != pdFALSE )
+ {
+ /* A context switch is required. Context switching is performed in
+ the PendSV interrupt. Pend the PendSV interrupt. */
+ portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
+ }
+ }
+ portENABLE_INTERRUPTS();
+}
+/*-----------------------------------------------------------*/
+
+#if( configUSE_TICKLESS_IDLE == 1 )
+
+ __attribute__((weak)) void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
+ {
+ uint32_t ulReloadValue, ulCompleteTickPeriods, ulCompletedSysTickDecrements;
+ TickType_t xModifiableIdleTime;
+
+ /* Make sure the SysTick reload value does not overflow the counter. */
+ if( xExpectedIdleTime > xMaximumPossibleSuppressedTicks )
+ {
+ xExpectedIdleTime = xMaximumPossibleSuppressedTicks;
+ }
+
+ /* Stop the SysTick momentarily. The time the SysTick is stopped for
+ is accounted for as best it can be, but using the tickless mode will
+ inevitably result in some tiny drift of the time maintained by the
+ kernel with respect to calendar time. */
+ portNVIC_SYSTICK_CTRL_REG &= ~portNVIC_SYSTICK_ENABLE_BIT;
+
+ /* Calculate the reload value required to wait xExpectedIdleTime
+ tick periods. -1 is used because this code will execute part way
+ through one of the tick periods. */
+ ulReloadValue = portNVIC_SYSTICK_CURRENT_VALUE_REG + ( ulTimerCountsForOneTick * ( xExpectedIdleTime - 1UL ) );
+ if( ulReloadValue > ulStoppedTimerCompensation )
+ {
+ ulReloadValue -= ulStoppedTimerCompensation;
+ }
+
+ /* Enter a critical section but don't use the taskENTER_CRITICAL()
+ method as that will mask interrupts that should exit sleep mode. */
+ __asm volatile( "cpsid i" ::: "memory" );
+ __asm volatile( "dsb" );
+ __asm volatile( "isb" );
+
+ /* If a context switch is pending or a task is waiting for the scheduler
+ to be unsuspended then abandon the low power entry. */
+ if( eTaskConfirmSleepModeStatus() == eAbortSleep )
+ {
+ /* Restart from whatever is left in the count register to complete
+ this tick period. */
+ portNVIC_SYSTICK_LOAD_REG = portNVIC_SYSTICK_CURRENT_VALUE_REG;
+
+ /* Restart SysTick. */
+ portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
+
+ /* Reset the reload register to the value required for normal tick
+ periods. */
+ portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
+
+ /* Re-enable interrupts - see comments above the cpsid instruction()
+ above. */
+ __asm volatile( "cpsie i" ::: "memory" );
+ }
+ else
+ {
+ /* Set the new reload value. */
+ portNVIC_SYSTICK_LOAD_REG = ulReloadValue;
+
+ /* Clear the SysTick count flag and set the count value back to
+ zero. */
+ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
+
+ /* Restart SysTick. */
+ portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
+
+ /* Sleep until something happens. configPRE_SLEEP_PROCESSING() can
+ set its parameter to 0 to indicate that its implementation contains
+ its own wait for interrupt or wait for event instruction, and so wfi
+ should not be executed again. However, the original expected idle
+ time variable must remain unmodified, so a copy is taken. */
+ xModifiableIdleTime = xExpectedIdleTime;
+ configPRE_SLEEP_PROCESSING( xModifiableIdleTime );
+ if( xModifiableIdleTime > 0 )
+ {
+ __asm volatile( "dsb" ::: "memory" );
+ __asm volatile( "wfi" );
+ __asm volatile( "isb" );
+ }
+ configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
+
+ /* Re-enable interrupts to allow the interrupt that brought the MCU
+ out of sleep mode to execute immediately. see comments above
+ __disable_interrupt() call above. */
+ __asm volatile( "cpsie i" ::: "memory" );
+ __asm volatile( "dsb" );
+ __asm volatile( "isb" );
+
+ /* Disable interrupts again because the clock is about to be stopped
+ and interrupts that execute while the clock is stopped will increase
+ any slippage between the time maintained by the RTOS and calendar
+ time. */
+ __asm volatile( "cpsid i" ::: "memory" );
+ __asm volatile( "dsb" );
+ __asm volatile( "isb" );
+
+ /* Disable the SysTick clock without reading the
+ portNVIC_SYSTICK_CTRL_REG register to ensure the
+ portNVIC_SYSTICK_COUNT_FLAG_BIT is not cleared if it is set. Again,
+ the time the SysTick is stopped for is accounted for as best it can
+ be, but using the tickless mode will inevitably result in some tiny
+ drift of the time maintained by the kernel with respect to calendar
+ time*/
+ portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT );
+
+ /* Determine if the SysTick clock has already counted to zero and
+ been set back to the current reload value (the reload back being
+ correct for the entire expected idle time) or if the SysTick is yet
+ to count to zero (in which case an interrupt other than the SysTick
+ must have brought the system out of sleep mode). */
+ if( ( portNVIC_SYSTICK_CTRL_REG & portNVIC_SYSTICK_COUNT_FLAG_BIT ) != 0 )
+ {
+ uint32_t ulCalculatedLoadValue;
+
+ /* The tick interrupt is already pending, and the SysTick count
+ reloaded with ulReloadValue. Reset the
+ portNVIC_SYSTICK_LOAD_REG with whatever remains of this tick
+ period. */
+ ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL ) - ( ulReloadValue - portNVIC_SYSTICK_CURRENT_VALUE_REG );
+
+ /* Don't allow a tiny value, or values that have somehow
+ underflowed because the post sleep hook did something
+ that took too long. */
+ if( ( ulCalculatedLoadValue < ulStoppedTimerCompensation ) || ( ulCalculatedLoadValue > ulTimerCountsForOneTick ) )
+ {
+ ulCalculatedLoadValue = ( ulTimerCountsForOneTick - 1UL );
+ }
+
+ portNVIC_SYSTICK_LOAD_REG = ulCalculatedLoadValue;
+
+ /* As the pending tick will be processed as soon as this
+ function exits, the tick value maintained by the tick is stepped
+ forward by one less than the time spent waiting. */
+ ulCompleteTickPeriods = xExpectedIdleTime - 1UL;
+ }
+ else
+ {
+ /* Something other than the tick interrupt ended the sleep.
+ Work out how long the sleep lasted rounded to complete tick
+ periods (not the ulReload value which accounted for part
+ ticks). */
+ ulCompletedSysTickDecrements = ( xExpectedIdleTime * ulTimerCountsForOneTick ) - portNVIC_SYSTICK_CURRENT_VALUE_REG;
+
+ /* How many complete tick periods passed while the processor
+ was waiting? */
+ ulCompleteTickPeriods = ulCompletedSysTickDecrements / ulTimerCountsForOneTick;
+
+ /* The reload value is set to whatever fraction of a single tick
+ period remains. */
+ portNVIC_SYSTICK_LOAD_REG = ( ( ulCompleteTickPeriods + 1UL ) * ulTimerCountsForOneTick ) - ulCompletedSysTickDecrements;
+ }
+
+ /* Restart SysTick so it runs from portNVIC_SYSTICK_LOAD_REG
+ again, then set portNVIC_SYSTICK_LOAD_REG back to its standard
+ value. */
+ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
+ portNVIC_SYSTICK_CTRL_REG |= portNVIC_SYSTICK_ENABLE_BIT;
+ vTaskStepTick( ulCompleteTickPeriods );
+ portNVIC_SYSTICK_LOAD_REG = ulTimerCountsForOneTick - 1UL;
+
+ /* Exit with interrpts enabled. */
+ __asm volatile( "cpsie i" ::: "memory" );
+ }
+ }
+
+#endif /* configUSE_TICKLESS_IDLE */
+/*-----------------------------------------------------------*/
+
+/*
+ * Setup the systick timer to generate the tick interrupts at the required
+ * frequency.
+ */
+__attribute__(( weak )) void vPortSetupTimerInterrupt( void )
+{
+ /* Calculate the constants required to configure the tick interrupt. */
+ #if( configUSE_TICKLESS_IDLE == 1 )
+ {
+ ulTimerCountsForOneTick = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ );
+ xMaximumPossibleSuppressedTicks = portMAX_24_BIT_NUMBER / ulTimerCountsForOneTick;
+ ulStoppedTimerCompensation = portMISSED_COUNTS_FACTOR / ( configCPU_CLOCK_HZ / configSYSTICK_CLOCK_HZ );
+ }
+ #endif /* configUSE_TICKLESS_IDLE */
+
+ /* Stop and clear the SysTick. */
+ portNVIC_SYSTICK_CTRL_REG = 0UL;
+ portNVIC_SYSTICK_CURRENT_VALUE_REG = 0UL;
+
+ /* Configure SysTick to interrupt at the requested rate. */
+ portNVIC_SYSTICK_LOAD_REG = ( configSYSTICK_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL;
+ portNVIC_SYSTICK_CTRL_REG = ( portNVIC_SYSTICK_CLK_BIT | portNVIC_SYSTICK_INT_BIT | portNVIC_SYSTICK_ENABLE_BIT );
+}
+/*-----------------------------------------------------------*/
+
+#if( configASSERT_DEFINED == 1 )
+
+ void vPortValidateInterruptPriority( void )
+ {
+ uint32_t ulCurrentInterrupt;
+ uint8_t ucCurrentPriority;
+
+ /* Obtain the number of the currently executing interrupt. */
+ __asm volatile( "mrs %0, ipsr" : "=r"( ulCurrentInterrupt ) :: "memory" );
+
+ /* Is the interrupt number a user defined interrupt? */
+ if( ulCurrentInterrupt >= portFIRST_USER_INTERRUPT_NUMBER )
+ {
+ /* Look up the interrupt's priority. */
+ ucCurrentPriority = pcInterruptPriorityRegisters[ ulCurrentInterrupt ];
+
+ /* The following assertion will fail if a service routine (ISR) for
+ an interrupt that has been assigned a priority above
+ configMAX_SYSCALL_INTERRUPT_PRIORITY calls an ISR safe FreeRTOS API
+ function. ISR safe FreeRTOS API functions must *only* be called
+ from interrupts that have been assigned a priority at or below
+ configMAX_SYSCALL_INTERRUPT_PRIORITY.
+
+ Numerically low interrupt priority numbers represent logically high
+ interrupt priorities, therefore the priority of the interrupt must
+ be set to a value equal to or numerically *higher* than
+ configMAX_SYSCALL_INTERRUPT_PRIORITY.
+
+ Interrupts that use the FreeRTOS API must not be left at their
+ default priority of zero as that is the highest possible priority,
+ which is guaranteed to be above configMAX_SYSCALL_INTERRUPT_PRIORITY,
+ and therefore also guaranteed to be invalid.
+
+ FreeRTOS maintains separate thread and ISR API functions to ensure
+ interrupt entry is as fast and simple as possible.
+
+ The following links provide detailed information:
+ http://www.freertos.org/RTOS-Cortex-M3-M4.html
+ http://www.freertos.org/FAQHelp.html */
+ configASSERT( ucCurrentPriority >= ucMaxSysCallPriority );
+ }
+
+ /* Priority grouping: The interrupt controller (NVIC) allows the bits
+ that define each interrupt's priority to be split between bits that
+ define the interrupt's pre-emption priority bits and bits that define
+ the interrupt's sub-priority. For simplicity all bits must be defined
+ to be pre-emption priority bits. The following assertion will fail if
+ this is not the case (if some bits represent a sub-priority).
+
+ If the application only uses CMSIS libraries for interrupt
+ configuration then the correct setting can be achieved on all Cortex-M
+ devices by calling NVIC_SetPriorityGrouping( 0 ); before starting the
+ scheduler. Note however that some vendor specific peripheral libraries
+ assume a non-zero priority group setting, in which cases using a value
+ of zero will result in unpredictable behaviour. */
+ configASSERT( ( portAIRCR_REG & portPRIORITY_GROUP_MASK ) <= ulMaxPRIGROUPValue );
+ }
+
+#endif /* configASSERT_DEFINED */
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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