2 FreeRTOS V7.0.0 - Copyright (C) 2011 Real Time Engineers Ltd.
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5 ***************************************************************************
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7 * FreeRTOS tutorial books are available in pdf and paperback. *
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8 * Complete, revised, and edited pdf reference manuals are also *
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11 * Purchasing FreeRTOS documentation will not only help you, by *
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12 * ensuring you get running as quickly as possible and with an *
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13 * in-depth knowledge of how to use FreeRTOS, it will also help *
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14 * the FreeRTOS project to continue with its mission of providing *
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15 * professional grade, cross platform, de facto standard solutions *
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16 * for microcontrollers - completely free of charge! *
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18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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20 * Thank you for using FreeRTOS, and thank you for your support! *
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22 ***************************************************************************
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25 This file is part of the FreeRTOS distribution.
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27 FreeRTOS is free software; you can redistribute it and/or modify it under
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28 the terms of the GNU General Public License (version 2) as published by the
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29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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30 >>>NOTE<<< The modification to the GPL is included to allow you to
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31 distribute a combined work that includes FreeRTOS without being obliged to
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32 provide the source code for proprietary components outside of the FreeRTOS
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33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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35 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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36 more details. You should have received a copy of the GNU General Public
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37 License and the FreeRTOS license exception along with FreeRTOS; if not it
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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39 by writing to Richard Barry, contact details for whom are available on the
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44 http://www.FreeRTOS.org - Documentation, latest information, license and
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47 http://www.SafeRTOS.com - A version that is certified for use in safety
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50 http://www.OpenRTOS.com - Commercial support, development, porting,
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51 licensing and training services.
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54 /* Kernel includes. */
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55 #include "FreeRTOS.h"
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59 #define portINITIAL_FORMAT_VECTOR ( ( portSTACK_TYPE ) 0x4000 )
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61 /* Supervisor mode set. */
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62 #define portINITIAL_STATUS_REGISTER ( ( portSTACK_TYPE ) 0x2000)
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64 /* The clock prescale into the timer peripheral. */
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65 #define portPRESCALE_VALUE ( ( unsigned char ) 10 )
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67 /* The clock frequency into the RTC. */
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68 #define portRTC_CLOCK_HZ ( ( unsigned long ) 1000 )
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70 asm void interrupt VectorNumber_VL1swi vPortYieldISR( void );
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71 static void prvSetupTimerInterrupt( void );
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73 /* Used to keep track of the number of nested calls to taskENTER_CRITICAL(). This
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74 will be set to 0 prior to the first task being started. */
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75 static unsigned long ulCriticalNesting = 0x9999UL;
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77 /*-----------------------------------------------------------*/
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79 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE * pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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82 unsigned long ulOriginalA5;
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84 __asm{ MOVE.L A5, ulOriginalA5 };
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87 *pxTopOfStack = (portSTACK_TYPE) 0xDEADBEEF;
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90 /* Exception stack frame starts with the return address. */
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91 *pxTopOfStack = ( portSTACK_TYPE ) pxCode;
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94 *pxTopOfStack = ( portINITIAL_FORMAT_VECTOR << 16UL ) | ( portINITIAL_STATUS_REGISTER );
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97 *pxTopOfStack = ( portSTACK_TYPE ) 0x0; /*FP*/
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98 pxTopOfStack -= 14; /* A5 to D0. */
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100 /* Parameter in A0. */
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101 *( pxTopOfStack + 8 ) = ( portSTACK_TYPE ) pvParameters;
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103 /* A5 must be maintained as it is resurved by the compiler. */
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104 *( pxTopOfStack + 13 ) = ulOriginalA5;
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106 return pxTopOfStack;
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108 /*-----------------------------------------------------------*/
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110 portBASE_TYPE xPortStartScheduler( void )
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112 extern void vPortStartFirstTask( void );
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114 ulCriticalNesting = 0UL;
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116 /* Configure a timer to generate the tick interrupt. */
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117 prvSetupTimerInterrupt();
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119 /* Start the first task executing. */
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120 vPortStartFirstTask();
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124 /*-----------------------------------------------------------*/
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126 static void prvSetupTimerInterrupt( void )
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128 /* Prescale by 1 - ie no prescale. */
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131 /* Compare match value. */
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132 RTCMOD = portRTC_CLOCK_HZ / configTICK_RATE_HZ;
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134 /* Enable the RTC to generate interrupts - interrupts are already disabled
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135 when this code executes. */
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138 /*-----------------------------------------------------------*/
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140 void vPortEndScheduler( void )
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142 /* Not implemented as there is nothing to return to. */
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144 /*-----------------------------------------------------------*/
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146 void vPortEnterCritical( void )
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148 if( ulCriticalNesting == 0UL )
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150 /* Guard against context switches being pended simultaneously with a
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151 critical section being entered. */
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154 portDISABLE_INTERRUPTS();
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155 if( INTC_FRC == 0UL )
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160 portENABLE_INTERRUPTS();
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164 ulCriticalNesting++;
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166 /*-----------------------------------------------------------*/
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168 void vPortExitCritical( void )
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170 ulCriticalNesting--;
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171 if( ulCriticalNesting == 0 )
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173 portENABLE_INTERRUPTS();
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176 /*-----------------------------------------------------------*/
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178 void vPortYieldHandler( void )
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180 unsigned long ulSavedInterruptMask;
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182 ulSavedInterruptMask = portSET_INTERRUPT_MASK_FROM_ISR();
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184 /* Note this will clear all forced interrupts - this is done for speed. */
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186 vTaskSwitchContext();
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188 portCLEAR_INTERRUPT_MASK_FROM_ISR( ulSavedInterruptMask );
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190 /*-----------------------------------------------------------*/
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192 void interrupt VectorNumber_Vrtc vPortTickISR( void )
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194 unsigned long ulSavedInterruptMask;
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196 /* Clear the interrupt. */
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197 RTCSC |= RTCSC_RTIF_MASK;
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199 /* Increment the RTOS tick. */
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200 ulSavedInterruptMask = portSET_INTERRUPT_MASK_FROM_ISR();
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202 vTaskIncrementTick();
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204 portCLEAR_INTERRUPT_MASK_FROM_ISR( ulSavedInterruptMask );
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206 /* If we are using the pre-emptive scheduler then also request a
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207 context switch as incrementing the tick could have unblocked a task. */
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208 #if configUSE_PREEMPTION == 1
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