2 FreeRTOS V7.6.0 - Copyright (C) 2013 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS provides completely free yet professionally developed, *
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10 * robust, strictly quality controlled, supported, and cross *
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11 * platform software that has become a de facto standard. *
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13 * Help yourself get started quickly and support the FreeRTOS *
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14 * project by purchasing a FreeRTOS tutorial book, reference *
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15 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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19 ***************************************************************************
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21 This file is part of the FreeRTOS distribution.
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23 FreeRTOS is free software; you can redistribute it and/or modify it under
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24 the terms of the GNU General Public License (version 2) as published by the
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25 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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27 >>! NOTE: The modification to the GPL is included to allow you to distribute
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28 >>! a combined work that includes FreeRTOS without being obliged to provide
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29 >>! the source code for proprietary components outside of the FreeRTOS
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32 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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33 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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34 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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35 link: http://www.freertos.org/a00114.html
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39 ***************************************************************************
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41 * Having a problem? Start by reading the FAQ "My application does *
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42 * not run, what could be wrong?" *
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44 * http://www.FreeRTOS.org/FAQHelp.html *
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46 ***************************************************************************
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48 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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49 license and Real Time Engineers Ltd. contact details.
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51 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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52 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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53 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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55 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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56 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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57 licenses offer ticketed support, indemnification and middleware.
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59 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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60 engineered and independently SIL3 certified version for use in safety and
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61 mission critical applications that require provable dependability.
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66 /*-----------------------------------------------------------
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67 * Implementation of functions defined in portable.h for the ST STR71x ARM7
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69 *----------------------------------------------------------*/
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71 /* Library includes. */
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75 /* Standard includes. */
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78 /* Scheduler includes. */
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79 #include "FreeRTOS.h"
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82 /* Constants required to setup the initial stack. */
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83 #define portINITIAL_SPSR ( ( StackType_t ) 0x1f ) /* System mode, ARM mode, interrupts enabled. */
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84 #define portTHUMB_MODE_BIT ( ( StackType_t ) 0x20 )
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85 #define portINSTRUCTION_SIZE ( ( StackType_t ) 4 )
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87 /* Constants required to handle critical sections. */
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88 #define portNO_CRITICAL_NESTING ( ( uint32_t ) 0 )
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90 #define portMICROS_PER_SECOND 1000000
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92 /*-----------------------------------------------------------*/
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94 /* Setup the watchdog to generate the tick interrupts. */
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95 static void prvSetupTimerInterrupt( void );
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97 /* ulCriticalNesting will get set to zero when the first task starts. It
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98 cannot be initialised to 0 as this will cause interrupts to be enabled
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99 during the kernel initialisation process. */
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100 uint32_t ulCriticalNesting = ( uint32_t ) 9999;
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102 /* Tick interrupt routines for cooperative and preemptive operation
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103 respectively. The preemptive version is not defined as __irq as it is called
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104 from an asm wrapper function. */
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105 __arm __irq void vPortNonPreemptiveTick( void );
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106 void vPortPreemptiveTick( void );
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108 /*-----------------------------------------------------------*/
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111 * Initialise the stack of a task to look exactly as if a call to
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112 * portSAVE_CONTEXT had been called.
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114 * See header file for description.
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116 StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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118 StackType_t *pxOriginalTOS;
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120 pxOriginalTOS = pxTopOfStack;
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122 /* To ensure asserts in tasks.c don't fail, although in this case the assert
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123 is not really required. */
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126 /* Setup the initial stack of the task. The stack is set exactly as
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127 expected by the portRESTORE_CONTEXT() macro. */
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129 /* First on the stack is the return address - which in this case is the
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130 start of the task. The offset is added to make the return address appear
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131 as it would within an IRQ ISR. */
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132 *pxTopOfStack = ( StackType_t ) pxCode + portINSTRUCTION_SIZE;
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135 *pxTopOfStack = ( StackType_t ) 0xaaaaaaaa; /* R14 */
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137 *pxTopOfStack = ( StackType_t ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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139 *pxTopOfStack = ( StackType_t ) 0x12121212; /* R12 */
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141 *pxTopOfStack = ( StackType_t ) 0x11111111; /* R11 */
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143 *pxTopOfStack = ( StackType_t ) 0x10101010; /* R10 */
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145 *pxTopOfStack = ( StackType_t ) 0x09090909; /* R9 */
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147 *pxTopOfStack = ( StackType_t ) 0x08080808; /* R8 */
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149 *pxTopOfStack = ( StackType_t ) 0x07070707; /* R7 */
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151 *pxTopOfStack = ( StackType_t ) 0x06060606; /* R6 */
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153 *pxTopOfStack = ( StackType_t ) 0x05050505; /* R5 */
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155 *pxTopOfStack = ( StackType_t ) 0x04040404; /* R4 */
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157 *pxTopOfStack = ( StackType_t ) 0x03030303; /* R3 */
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159 *pxTopOfStack = ( StackType_t ) 0x02020202; /* R2 */
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161 *pxTopOfStack = ( StackType_t ) 0x01010101; /* R1 */
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164 /* When the task starts is will expect to find the function parameter in
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166 *pxTopOfStack = ( StackType_t ) pvParameters; /* R0 */
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169 /* The status register is set for system mode, with interrupts enabled. */
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170 *pxTopOfStack = ( StackType_t ) portINITIAL_SPSR;
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172 if( ( ( uint32_t ) pxCode & 0x01UL ) != 0x00UL )
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174 /* We want the task to start in thumb mode. */
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175 *pxTopOfStack |= portTHUMB_MODE_BIT;
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180 /* Interrupt flags cannot always be stored on the stack and will
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181 instead be stored in a variable, which is then saved as part of the
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183 *pxTopOfStack = portNO_CRITICAL_NESTING;
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185 return pxTopOfStack;
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187 /*-----------------------------------------------------------*/
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189 BaseType_t xPortStartScheduler( void )
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191 extern void vPortStartFirstTask( void );
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193 /* Start the timer that generates the tick ISR. Interrupts are disabled
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195 prvSetupTimerInterrupt();
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197 /* Start the first task. */
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198 vPortStartFirstTask();
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200 /* Should not get here! */
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203 /*-----------------------------------------------------------*/
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205 void vPortEndScheduler( void )
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207 /* It is unlikely that the ARM port will require this function as there
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208 is nothing to return to. */
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210 /*-----------------------------------------------------------*/
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212 /* The cooperative scheduler requires a normal IRQ service routine to
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213 simply increment the system tick. */
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214 __arm __irq void vPortNonPreemptiveTick( void )
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216 /* Increment the tick count - which may wake some tasks but as the
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217 preemptive scheduler is not being used any woken task is not given
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218 processor time no matter what its priority. */
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219 xTaskIncrementTick();
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221 /* Clear the interrupt in the watchdog and EIC. */
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225 /*-----------------------------------------------------------*/
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227 /* This function is called from an asm wrapper, so does not require the __irq
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229 void vPortPreemptiveTick( void )
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231 /* Increment the tick counter. */
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232 if( xTaskIncrementTick() != pdFALSE )
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234 /* Select a new task to execute. */
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235 vTaskSwitchContext();
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238 /* Clear the interrupt in the watchdog and EIC. */
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242 /*-----------------------------------------------------------*/
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244 static void prvSetupTimerInterrupt( void )
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246 /* Set the watchdog up to generate a periodic tick. */
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247 WDG_ECITConfig( DISABLE );
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248 WDG_CntOnOffConfig( DISABLE );
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249 WDG_PeriodValueConfig( portMICROS_PER_SECOND / configTICK_RATE_HZ );
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251 /* Setup the tick interrupt in the EIC. */
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252 EIC_IRQChannelPriorityConfig( WDG_IRQChannel, 1 );
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253 EIC_IRQChannelConfig( WDG_IRQChannel, ENABLE );
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254 EIC_IRQConfig( ENABLE );
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255 WDG_ECITConfig( ENABLE );
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257 /* Start the timer - interrupts are actually disabled at this point so
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258 it is safe to do this here. */
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259 WDG_CntOnOffConfig( ENABLE );
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261 /*-----------------------------------------------------------*/
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263 __arm __interwork void vPortEnterCritical( void )
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265 /* Disable interrupts first! */
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266 __disable_interrupt();
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268 /* Now interrupts are disabled ulCriticalNesting can be accessed
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269 directly. Increment ulCriticalNesting to keep a count of how many times
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270 portENTER_CRITICAL() has been called. */
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271 ulCriticalNesting++;
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273 /*-----------------------------------------------------------*/
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275 __arm __interwork void vPortExitCritical( void )
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277 if( ulCriticalNesting > portNO_CRITICAL_NESTING )
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279 /* Decrement the nesting count as we are leaving a critical section. */
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280 ulCriticalNesting--;
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282 /* If the nesting level has reached zero then interrupts should be
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284 if( ulCriticalNesting == portNO_CRITICAL_NESTING )
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286 __enable_interrupt();
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290 /*-----------------------------------------------------------*/
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