2 FreeRTOS V7.1.1 - Copyright (C) 2012 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 ***************************************************************************
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46 * Having a problem? Start by reading the FAQ "My application does *
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47 * not run, what could be wrong? *
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49 * http://www.FreeRTOS.org/FAQHelp.html *
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51 ***************************************************************************
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54 http://www.FreeRTOS.org - Documentation, training, latest information,
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55 license and contact details.
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57 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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58 including FreeRTOS+Trace - an indispensable productivity tool.
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60 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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61 the code with commercial support, indemnification, and middleware, under
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62 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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63 provide a safety engineered and independently SIL3 certified version under
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64 the SafeRTOS brand: http://www.SafeRTOS.com.
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70 + Introduced the configKERNEL_INTERRUPT_PRIORITY definition.
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73 /*-----------------------------------------------------------
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74 * Implementation of functions defined in portable.h for the PIC24 port.
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75 *----------------------------------------------------------*/
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77 /* Scheduler include files. */
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78 #include "FreeRTOS.h"
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81 /* Hardware specifics. */
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82 #define portBIT_SET 1
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83 #define portTIMER_PRESCALE 8
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84 #define portINITIAL_SR 0
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86 /* Defined for backward compatability with project created prior to
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87 FreeRTOS.org V4.3.0. */
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88 #ifndef configKERNEL_INTERRUPT_PRIORITY
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89 #define configKERNEL_INTERRUPT_PRIORITY 1
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92 /* The program counter is only 23 bits. */
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93 #define portUNUSED_PR_BITS 0x7f
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95 /* Records the nesting depth of calls to portENTER_CRITICAL(). */
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96 unsigned portBASE_TYPE uxCriticalNesting = 0xef;
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98 #if configKERNEL_INTERRUPT_PRIORITY != 1
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99 #error If configKERNEL_INTERRUPT_PRIORITY is not 1 then the #32 in the following macros needs changing to equal the portINTERRUPT_BITS value, which is ( configKERNEL_INTERRUPT_PRIORITY << 5 )
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102 #ifdef MPLAB_PIC24_PORT
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104 #define portRESTORE_CONTEXT() \
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105 asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
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106 "MOV [W0], W15 \n" \
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107 "POP W0 \n" /* Restore the critical nesting counter for the task. */ \
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108 "MOV W0, _uxCriticalNesting \n" \
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112 "POP RCOUNT \n" /* Restore the registers from the stack. */ \
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123 #endif /* MPLAB_PIC24_PORT */
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125 #ifdef MPLAB_DSPIC_PORT
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127 #define portRESTORE_CONTEXT() \
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128 asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
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129 "MOV [W0], W15 \n" \
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130 "POP W0 \n" /* Restore the critical nesting counter for the task. */ \
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131 "MOV W0, _uxCriticalNesting \n" \
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136 "POP DOSTARTH \n" \
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137 "POP DOSTARTL \n" \
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146 "POP RCOUNT \n" /* Restore the registers from the stack. */ \
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157 #endif /* MPLAB_DSPIC_PORT */
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160 * Setup the timer used to generate the tick interrupt.
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162 static void prvSetupTimerInterrupt( void );
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165 * See header file for description.
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167 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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169 unsigned short usCode;
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172 const portSTACK_TYPE xInitialStack[] =
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188 0xcdce, /* RCOUNT */
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189 0xabac, /* TBLPAG */
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191 /* dsPIC specific registers. */
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192 #ifdef MPLAB_DSPIC_PORT
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193 0x0202, /* ACCAL */
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194 0x0303, /* ACCAH */
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195 0x0404, /* ACCAU */
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196 0x0505, /* ACCBL */
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197 0x0606, /* ACCBH */
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198 0x0707, /* ACCBU */
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199 0x0808, /* DCOUNT */
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200 0x090a, /* DOSTARTL */
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201 0x1010, /* DOSTARTH */
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202 0x1110, /* DOENDL */
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203 0x1212, /* DOENDH */
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207 /* Setup the stack as if a yield had occurred.
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209 Save the low bytes of the program counter. */
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210 usCode = ( unsigned short ) pxCode;
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211 *pxTopOfStack = ( portSTACK_TYPE ) usCode;
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214 /* Save the high byte of the program counter. This will always be zero
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215 here as it is passed in a 16bit pointer. If the address is greater than
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216 16 bits then the pointer will point to a jump table. */
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217 *pxTopOfStack = ( portSTACK_TYPE ) 0;
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220 /* Status register with interrupts enabled. */
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221 *pxTopOfStack = portINITIAL_SR;
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224 /* Parameters are passed in W0. */
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225 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
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228 for( i = 0; i < ( sizeof( xInitialStack ) / sizeof( portSTACK_TYPE ) ); i++ )
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230 *pxTopOfStack = xInitialStack[ i ];
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234 *pxTopOfStack = CORCON;
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236 *pxTopOfStack = PSVPAG;
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239 /* Finally the critical nesting depth. */
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240 *pxTopOfStack = 0x00;
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243 return pxTopOfStack;
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245 /*-----------------------------------------------------------*/
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247 portBASE_TYPE xPortStartScheduler( void )
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249 /* Setup a timer for the tick ISR. */
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250 prvSetupTimerInterrupt();
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252 /* Restore the context of the first task to run. */
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253 portRESTORE_CONTEXT();
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255 /* Simulate the end of the yield function. */
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256 asm volatile ( "return" );
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258 /* Should not reach here. */
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261 /*-----------------------------------------------------------*/
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263 void vPortEndScheduler( void )
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265 /* It is unlikely that the scheduler for the PIC port will get stopped
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266 once running. If required disable the tick interrupt here, then return
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267 to xPortStartScheduler(). */
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269 /*-----------------------------------------------------------*/
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272 * Setup a timer for a regular tick.
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274 static void prvSetupTimerInterrupt( void )
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276 const unsigned long ulCompareMatch = ( ( configCPU_CLOCK_HZ / portTIMER_PRESCALE ) / configTICK_RATE_HZ ) - 1;
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278 /* Prescale of 8. */
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282 PR1 = ( unsigned short ) ulCompareMatch;
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284 /* Setup timer 1 interrupt priority. */
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285 IPC0bits.T1IP = configKERNEL_INTERRUPT_PRIORITY;
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287 /* Clear the interrupt as a starting condition. */
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290 /* Enable the interrupt. */
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293 /* Setup the prescale value. */
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294 T1CONbits.TCKPS0 = 1;
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295 T1CONbits.TCKPS1 = 0;
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297 /* Start the timer. */
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300 /*-----------------------------------------------------------*/
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302 void vPortEnterCritical( void )
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304 portDISABLE_INTERRUPTS();
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305 uxCriticalNesting++;
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307 /*-----------------------------------------------------------*/
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309 void vPortExitCritical( void )
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311 uxCriticalNesting--;
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312 if( uxCriticalNesting == 0 )
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314 portENABLE_INTERRUPTS();
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317 /*-----------------------------------------------------------*/
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319 void __attribute__((__interrupt__, auto_psv)) _T1Interrupt( void )
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321 /* Clear the timer interrupt. */
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324 vTaskIncrementTick();
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326 #if configUSE_PREEMPTION == 1
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projects / freertos / blob