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267 lines
9.6 KiB
C
267 lines
9.6 KiB
C
/*
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FreeRTOS V7.1.0 - Copyright (C) 2011 Real Time Engineers Ltd.
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***************************************************************************
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* *
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* FreeRTOS tutorial books are available in pdf and paperback. *
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* Complete, revised, and edited pdf reference manuals are also *
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* available. *
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* *
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* Purchasing FreeRTOS documentation will not only help you, by *
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* ensuring you get running as quickly as possible and with an *
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* in-depth knowledge of how to use FreeRTOS, it will also help *
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* the FreeRTOS project to continue with its mission of providing *
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* professional grade, cross platform, de facto standard solutions *
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* for microcontrollers - completely free of charge! *
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* *
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* >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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* *
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* Thank you for using FreeRTOS, and thank you for your support! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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>>>NOTE<<< The modification to the GPL is included to allow you to
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distribute a combined work that includes FreeRTOS without being obliged to
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provide the source code for proprietary components outside of the FreeRTOS
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kernel. FreeRTOS is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details. You should have received a copy of the GNU General Public
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License and the FreeRTOS license exception along with FreeRTOS; if not it
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can be viewed here: http://www.freertos.org/a00114.html and also obtained
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by writing to Richard Barry, contact details for whom are available on the
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FreeRTOS WEB site.
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1 tab == 4 spaces!
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http://www.FreeRTOS.org - Documentation, latest information, license and
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contact details.
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http://www.SafeRTOS.com - A version that is certified for use in safety
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critical systems.
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http://www.OpenRTOS.com - Commercial support, development, porting,
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licensing and training services.
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*/
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/*-----------------------------------------------------------
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* Implementation of functions defined in portable.h for the ST STR75x ARM7
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* port.
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*----------------------------------------------------------*/
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/* Library includes. */
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#include "75x_tb.h"
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#include "75x_eic.h"
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/* Scheduler includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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/* Constants required to setup the initial stack. */
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#define portINITIAL_SPSR ( ( portSTACK_TYPE ) 0x3f ) /* System mode, THUMB mode, interrupts enabled. */
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#define portINSTRUCTION_SIZE ( ( portSTACK_TYPE ) 4 )
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/* Constants required to handle critical sections. */
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#define portNO_CRITICAL_NESTING ( ( unsigned long ) 0 )
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/* Prescale used on the timer clock when calculating the tick period. */
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#define portPRESCALE 20
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/*-----------------------------------------------------------*/
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/* Setup the TB to generate the tick interrupts. */
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static void prvSetupTimerInterrupt( void );
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/* ulCriticalNesting will get set to zero when the first task starts. It
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cannot be initialised to 0 as this will cause interrupts to be enabled
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during the kernel initialisation process. */
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unsigned long ulCriticalNesting = ( unsigned long ) 9999;
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/* Tick interrupt routines for preemptive operation. */
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__arm void vPortPreemptiveTick( void );
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/*-----------------------------------------------------------*/
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/*
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* Initialise the stack of a task to look exactly as if a call to
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* portSAVE_CONTEXT had been called.
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*
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* See header file for description.
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*/
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portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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{
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portSTACK_TYPE *pxOriginalTOS;
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pxOriginalTOS = pxTopOfStack;
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/* To ensure asserts in tasks.c don't fail, although in this case the assert
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is not really required. */
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pxTopOfStack--;
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/* Setup the initial stack of the task. The stack is set exactly as
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expected by the portRESTORE_CONTEXT() macro. */
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/* First on the stack is the return address - which in this case is the
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start of the task. The offset is added to make the return address appear
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as it would within an IRQ ISR. */
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*pxTopOfStack = ( portSTACK_TYPE ) pxCode + portINSTRUCTION_SIZE;
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0xaaaaaaaa; /* R14 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x12121212; /* R12 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x11111111; /* R11 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x10101010; /* R10 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x09090909; /* R9 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x08080808; /* R8 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x07070707; /* R7 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x06060606; /* R6 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x05050505; /* R5 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x04040404; /* R4 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x03030303; /* R3 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x02020202; /* R2 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x01010101; /* R1 */
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pxTopOfStack--;
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/* When the task starts is will expect to find the function parameter in
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R0. */
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*pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */
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pxTopOfStack--;
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/* The status register is set for system mode, with interrupts enabled. */
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*pxTopOfStack = ( portSTACK_TYPE ) portINITIAL_SPSR;
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pxTopOfStack--;
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/* Interrupt flags cannot always be stored on the stack and will
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instead be stored in a variable, which is then saved as part of the
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tasks context. */
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*pxTopOfStack = portNO_CRITICAL_NESTING;
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return pxTopOfStack;
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}
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/*-----------------------------------------------------------*/
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portBASE_TYPE xPortStartScheduler( void )
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{
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extern void vPortStartFirstTask( void );
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/* Start the timer that generates the tick ISR. Interrupts are disabled
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here already. */
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prvSetupTimerInterrupt();
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/* Start the first task. */
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vPortStartFirstTask();
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/* Should not get here! */
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return 0;
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}
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/*-----------------------------------------------------------*/
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void vPortEndScheduler( void )
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{
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/* It is unlikely that the ARM port will require this function as there
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is nothing to return to. */
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}
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/*-----------------------------------------------------------*/
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__arm void vPortPreemptiveTick( void )
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{
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/* Increment the tick counter. */
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vTaskIncrementTick();
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/* The new tick value might unblock a task. Ensure the highest task that
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is ready to execute is the task that will execute when the tick ISR
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exits. */
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#if configUSE_PREEMPTION == 1
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vTaskSwitchContext();
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#endif
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TB_ClearITPendingBit( TB_IT_Update );
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}
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/*-----------------------------------------------------------*/
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static void prvSetupTimerInterrupt( void )
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{
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EIC_IRQInitTypeDef EIC_IRQInitStructure;
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TB_InitTypeDef TB_InitStructure;
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/* Setup the EIC for the TB. */
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EIC_IRQInitStructure.EIC_IRQChannelCmd = ENABLE;
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EIC_IRQInitStructure.EIC_IRQChannel = TB_IRQChannel;
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EIC_IRQInitStructure.EIC_IRQChannelPriority = 1;
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EIC_IRQInit(&EIC_IRQInitStructure);
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/* Setup the TB for the generation of the tick interrupt. */
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TB_InitStructure.TB_Mode = TB_Mode_Timing;
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TB_InitStructure.TB_CounterMode = TB_CounterMode_Down;
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TB_InitStructure.TB_Prescaler = portPRESCALE - 1;
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TB_InitStructure.TB_AutoReload = ( ( configCPU_CLOCK_HZ / portPRESCALE ) / configTICK_RATE_HZ );
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TB_Init(&TB_InitStructure);
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/* Enable TB Update interrupt */
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TB_ITConfig(TB_IT_Update, ENABLE);
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/* Clear TB Update interrupt pending bit */
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TB_ClearITPendingBit(TB_IT_Update);
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/* Enable TB */
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TB_Cmd(ENABLE);
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}
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/*-----------------------------------------------------------*/
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__arm __interwork void vPortEnterCritical( void )
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{
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/* Disable interrupts first! */
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__disable_interrupt();
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/* Now interrupts are disabled ulCriticalNesting can be accessed
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directly. Increment ulCriticalNesting to keep a count of how many times
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portENTER_CRITICAL() has been called. */
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ulCriticalNesting++;
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}
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/*-----------------------------------------------------------*/
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__arm __interwork void vPortExitCritical( void )
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{
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if( ulCriticalNesting > portNO_CRITICAL_NESTING )
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{
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/* Decrement the nesting count as we are leaving a critical section. */
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ulCriticalNesting--;
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/* If the nesting level has reached zero then interrupts should be
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re-enabled. */
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if( ulCriticalNesting == portNO_CRITICAL_NESTING )
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{
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__enable_interrupt();
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}
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}
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}
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/*-----------------------------------------------------------*/
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