2 FreeRTOS V7.5.1 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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6 ***************************************************************************
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8 * FreeRTOS provides completely free yet professionally developed, *
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9 * robust, strictly quality controlled, supported, and cross *
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10 * platform software that has become a de facto standard. *
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12 * Help yourself get started quickly and support the FreeRTOS *
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13 * project by purchasing a FreeRTOS tutorial book, reference *
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14 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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18 ***************************************************************************
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20 This file is part of the FreeRTOS distribution.
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22 FreeRTOS is free software; you can redistribute it and/or modify it under
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23 the terms of the GNU General Public License (version 2) as published by the
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24 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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26 >>! NOTE: The modification to the GPL is included to allow you to distribute
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27 >>! a combined work that includes FreeRTOS without being obliged to provide
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28 >>! the source code for proprietary components outside of the FreeRTOS
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31 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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32 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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33 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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34 link: http://www.freertos.org/a00114.html
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38 ***************************************************************************
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40 * Having a problem? Start by reading the FAQ "My application does *
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41 * not run, what could be wrong?" *
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43 * http://www.FreeRTOS.org/FAQHelp.html *
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45 ***************************************************************************
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47 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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48 license and Real Time Engineers Ltd. contact details.
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50 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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51 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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52 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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54 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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55 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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56 licenses offer ticketed support, indemnification and middleware.
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58 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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59 engineered and independently SIL3 certified version for use in safety and
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60 mission critical applications that require provable dependability.
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65 /*-----------------------------------------------------------
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66 * Implementation of functions defined in portable.h for the ST STR75x ARM7
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68 *----------------------------------------------------------*/
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70 /* Library includes. */
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72 #include "75x_eic.h"
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74 /* Scheduler includes. */
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75 #include "FreeRTOS.h"
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78 /* Constants required to setup the initial stack. */
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79 #define portINITIAL_SPSR ( ( portSTACK_TYPE ) 0x3f ) /* System mode, THUMB mode, interrupts enabled. */
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80 #define portINSTRUCTION_SIZE ( ( portSTACK_TYPE ) 4 )
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82 /* Constants required to handle critical sections. */
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83 #define portNO_CRITICAL_NESTING ( ( unsigned long ) 0 )
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85 /* Prescale used on the timer clock when calculating the tick period. */
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86 #define portPRESCALE 20
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89 /*-----------------------------------------------------------*/
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91 /* Setup the TB to generate the tick interrupts. */
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92 static void prvSetupTimerInterrupt( void );
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94 /* ulCriticalNesting will get set to zero when the first task starts. It
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95 cannot be initialised to 0 as this will cause interrupts to be enabled
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96 during the kernel initialisation process. */
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97 unsigned long ulCriticalNesting = ( unsigned long ) 9999;
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99 /* Tick interrupt routines for preemptive operation. */
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100 __arm void vPortPreemptiveTick( void );
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102 /*-----------------------------------------------------------*/
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105 * Initialise the stack of a task to look exactly as if a call to
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106 * portSAVE_CONTEXT had been called.
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108 * See header file for description.
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110 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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112 portSTACK_TYPE *pxOriginalTOS;
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114 pxOriginalTOS = pxTopOfStack;
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116 /* To ensure asserts in tasks.c don't fail, although in this case the assert
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117 is not really required. */
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120 /* Setup the initial stack of the task. The stack is set exactly as
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121 expected by the portRESTORE_CONTEXT() macro. */
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123 /* First on the stack is the return address - which in this case is the
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124 start of the task. The offset is added to make the return address appear
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125 as it would within an IRQ ISR. */
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126 *pxTopOfStack = ( portSTACK_TYPE ) pxCode + portINSTRUCTION_SIZE;
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129 *pxTopOfStack = ( portSTACK_TYPE ) 0xaaaaaaaa; /* R14 */
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131 *pxTopOfStack = ( portSTACK_TYPE ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
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133 *pxTopOfStack = ( portSTACK_TYPE ) 0x12121212; /* R12 */
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135 *pxTopOfStack = ( portSTACK_TYPE ) 0x11111111; /* R11 */
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137 *pxTopOfStack = ( portSTACK_TYPE ) 0x10101010; /* R10 */
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139 *pxTopOfStack = ( portSTACK_TYPE ) 0x09090909; /* R9 */
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141 *pxTopOfStack = ( portSTACK_TYPE ) 0x08080808; /* R8 */
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143 *pxTopOfStack = ( portSTACK_TYPE ) 0x07070707; /* R7 */
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145 *pxTopOfStack = ( portSTACK_TYPE ) 0x06060606; /* R6 */
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147 *pxTopOfStack = ( portSTACK_TYPE ) 0x05050505; /* R5 */
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149 *pxTopOfStack = ( portSTACK_TYPE ) 0x04040404; /* R4 */
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151 *pxTopOfStack = ( portSTACK_TYPE ) 0x03030303; /* R3 */
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153 *pxTopOfStack = ( portSTACK_TYPE ) 0x02020202; /* R2 */
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155 *pxTopOfStack = ( portSTACK_TYPE ) 0x01010101; /* R1 */
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158 /* When the task starts is will expect to find the function parameter in
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160 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */
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163 /* The status register is set for system mode, with interrupts enabled. */
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164 *pxTopOfStack = ( portSTACK_TYPE ) portINITIAL_SPSR;
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167 /* Interrupt flags cannot always be stored on the stack and will
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168 instead be stored in a variable, which is then saved as part of the
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170 *pxTopOfStack = portNO_CRITICAL_NESTING;
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172 return pxTopOfStack;
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174 /*-----------------------------------------------------------*/
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176 portBASE_TYPE xPortStartScheduler( void )
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178 extern void vPortStartFirstTask( void );
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180 /* Start the timer that generates the tick ISR. Interrupts are disabled
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182 prvSetupTimerInterrupt();
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184 /* Start the first task. */
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185 vPortStartFirstTask();
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187 /* Should not get here! */
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190 /*-----------------------------------------------------------*/
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192 void vPortEndScheduler( void )
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194 /* It is unlikely that the ARM port will require this function as there
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195 is nothing to return to. */
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197 /*-----------------------------------------------------------*/
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199 __arm void vPortPreemptiveTick( void )
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201 /* Increment the tick counter. */
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202 if( xTaskIncrementTick() != pdFALSE )
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204 /* Select a new task to execute. */
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205 vTaskSwitchContext();
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208 TB_ClearITPendingBit( TB_IT_Update );
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210 /*-----------------------------------------------------------*/
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212 static void prvSetupTimerInterrupt( void )
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214 EIC_IRQInitTypeDef EIC_IRQInitStructure;
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215 TB_InitTypeDef TB_InitStructure;
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217 /* Setup the EIC for the TB. */
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218 EIC_IRQInitStructure.EIC_IRQChannelCmd = ENABLE;
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219 EIC_IRQInitStructure.EIC_IRQChannel = TB_IRQChannel;
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220 EIC_IRQInitStructure.EIC_IRQChannelPriority = 1;
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221 EIC_IRQInit(&EIC_IRQInitStructure);
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223 /* Setup the TB for the generation of the tick interrupt. */
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224 TB_InitStructure.TB_Mode = TB_Mode_Timing;
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225 TB_InitStructure.TB_CounterMode = TB_CounterMode_Down;
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226 TB_InitStructure.TB_Prescaler = portPRESCALE - 1;
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227 TB_InitStructure.TB_AutoReload = ( ( configCPU_CLOCK_HZ / portPRESCALE ) / configTICK_RATE_HZ );
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228 TB_Init(&TB_InitStructure);
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230 /* Enable TB Update interrupt */
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231 TB_ITConfig(TB_IT_Update, ENABLE);
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233 /* Clear TB Update interrupt pending bit */
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234 TB_ClearITPendingBit(TB_IT_Update);
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239 /*-----------------------------------------------------------*/
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241 __arm __interwork void vPortEnterCritical( void )
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243 /* Disable interrupts first! */
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244 __disable_interrupt();
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246 /* Now interrupts are disabled ulCriticalNesting can be accessed
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247 directly. Increment ulCriticalNesting to keep a count of how many times
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248 portENTER_CRITICAL() has been called. */
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249 ulCriticalNesting++;
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251 /*-----------------------------------------------------------*/
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253 __arm __interwork void vPortExitCritical( void )
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255 if( ulCriticalNesting > portNO_CRITICAL_NESTING )
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257 /* Decrement the nesting count as we are leaving a critical section. */
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258 ulCriticalNesting--;
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260 /* If the nesting level has reached zero then interrupts should be
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262 if( ulCriticalNesting == portNO_CRITICAL_NESTING )
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264 __enable_interrupt();
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268 /*-----------------------------------------------------------*/
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