2 FreeRTOS V7.4.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not it can be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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78 + Introduced the configKERNEL_INTERRUPT_PRIORITY definition.
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81 /*-----------------------------------------------------------
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82 * Implementation of functions defined in portable.h for the PIC24 port.
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83 *----------------------------------------------------------*/
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85 /* Scheduler include files. */
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86 #include "FreeRTOS.h"
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89 /* Hardware specifics. */
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90 #define portBIT_SET 1
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91 #define portTIMER_PRESCALE 8
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92 #define portINITIAL_SR 0
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94 /* Defined for backward compatability with project created prior to
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95 FreeRTOS.org V4.3.0. */
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96 #ifndef configKERNEL_INTERRUPT_PRIORITY
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97 #define configKERNEL_INTERRUPT_PRIORITY 1
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100 /* The program counter is only 23 bits. */
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101 #define portUNUSED_PR_BITS 0x7f
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103 /* Records the nesting depth of calls to portENTER_CRITICAL(). */
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104 unsigned portBASE_TYPE uxCriticalNesting = 0xef;
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106 #if configKERNEL_INTERRUPT_PRIORITY != 1
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107 #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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110 #ifdef MPLAB_PIC24_PORT
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113 #define portRESTORE_CONTEXT() \
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114 asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
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115 "MOV [W0], W15 \n" \
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116 "POP W0 \n" /* Restore the critical nesting counter for the task. */ \
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117 "MOV W0, _uxCriticalNesting \n" \
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122 "POP RCOUNT \n" /* Restore the registers from the stack. */ \
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132 #else /* __HAS_EDS__ */
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133 #define portRESTORE_CONTEXT() \
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134 asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
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135 "MOV [W0], W15 \n" \
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136 "POP W0 \n" /* Restore the critical nesting counter for the task. */ \
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137 "MOV W0, _uxCriticalNesting \n" \
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141 "POP RCOUNT \n" /* Restore the registers from the stack. */ \
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151 #endif /* __HAS_EDS__ */
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152 #endif /* MPLAB_PIC24_PORT */
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154 #ifdef MPLAB_DSPIC_PORT
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156 #define portRESTORE_CONTEXT() \
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157 asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
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158 "MOV [W0], W15 \n" \
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159 "POP W0 \n" /* Restore the critical nesting counter for the task. */ \
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160 "MOV W0, _uxCriticalNesting \n" \
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165 "POP DOSTARTH \n" \
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166 "POP DOSTARTL \n" \
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175 "POP RCOUNT \n" /* Restore the registers from the stack. */ \
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186 #endif /* MPLAB_DSPIC_PORT */
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189 * Setup the timer used to generate the tick interrupt.
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191 static void prvSetupTimerInterrupt( void );
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194 * See header file for description.
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196 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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198 unsigned short usCode;
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201 const portSTACK_TYPE xInitialStack[] =
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217 0xcdce, /* RCOUNT */
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218 0xabac, /* TBLPAG */
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220 /* dsPIC specific registers. */
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221 #ifdef MPLAB_DSPIC_PORT
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222 0x0202, /* ACCAL */
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223 0x0303, /* ACCAH */
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224 0x0404, /* ACCAU */
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225 0x0505, /* ACCBL */
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226 0x0606, /* ACCBH */
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227 0x0707, /* ACCBU */
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228 0x0808, /* DCOUNT */
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229 0x090a, /* DOSTARTL */
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230 0x1010, /* DOSTARTH */
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231 0x1110, /* DOENDL */
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232 0x1212, /* DOENDH */
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236 /* Setup the stack as if a yield had occurred.
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238 Save the low bytes of the program counter. */
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239 usCode = ( unsigned short ) pxCode;
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240 *pxTopOfStack = ( portSTACK_TYPE ) usCode;
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243 /* Save the high byte of the program counter. This will always be zero
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244 here as it is passed in a 16bit pointer. If the address is greater than
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245 16 bits then the pointer will point to a jump table. */
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246 *pxTopOfStack = ( portSTACK_TYPE ) 0;
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249 /* Status register with interrupts enabled. */
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250 *pxTopOfStack = portINITIAL_SR;
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253 /* Parameters are passed in W0. */
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254 *pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
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257 for( i = 0; i < ( sizeof( xInitialStack ) / sizeof( portSTACK_TYPE ) ); i++ )
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259 *pxTopOfStack = xInitialStack[ i ];
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263 *pxTopOfStack = CORCON;
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266 #if defined(__HAS_EDS__)
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267 *pxTopOfStack = DSRPAG;
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269 *pxTopOfStack = DSWPAG;
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271 #else /* __HAS_EDS__ */
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272 *pxTopOfStack = PSVPAG;
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274 #endif /* __HAS_EDS__ */
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276 /* Finally the critical nesting depth. */
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277 *pxTopOfStack = 0x00;
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280 return pxTopOfStack;
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282 /*-----------------------------------------------------------*/
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284 portBASE_TYPE xPortStartScheduler( void )
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286 /* Setup a timer for the tick ISR. */
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287 prvSetupTimerInterrupt();
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289 /* Restore the context of the first task to run. */
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290 portRESTORE_CONTEXT();
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292 /* Simulate the end of the yield function. */
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293 asm volatile ( "return" );
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295 /* Should not reach here. */
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298 /*-----------------------------------------------------------*/
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300 void vPortEndScheduler( void )
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302 /* It is unlikely that the scheduler for the PIC port will get stopped
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303 once running. If required disable the tick interrupt here, then return
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304 to xPortStartScheduler(). */
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306 /*-----------------------------------------------------------*/
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309 * Setup a timer for a regular tick.
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311 static void prvSetupTimerInterrupt( void )
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313 const unsigned long ulCompareMatch = ( ( configCPU_CLOCK_HZ / portTIMER_PRESCALE ) / configTICK_RATE_HZ ) - 1;
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315 /* Prescale of 8. */
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319 PR1 = ( unsigned short ) ulCompareMatch;
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321 /* Setup timer 1 interrupt priority. */
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322 IPC0bits.T1IP = configKERNEL_INTERRUPT_PRIORITY;
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324 /* Clear the interrupt as a starting condition. */
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327 /* Enable the interrupt. */
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330 /* Setup the prescale value. */
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331 T1CONbits.TCKPS0 = 1;
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332 T1CONbits.TCKPS1 = 0;
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334 /* Start the timer. */
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337 /*-----------------------------------------------------------*/
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339 void vPortEnterCritical( void )
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341 portDISABLE_INTERRUPTS();
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342 uxCriticalNesting++;
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344 /*-----------------------------------------------------------*/
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346 void vPortExitCritical( void )
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348 uxCriticalNesting--;
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349 if( uxCriticalNesting == 0 )
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351 portENABLE_INTERRUPTS();
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354 /*-----------------------------------------------------------*/
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356 void __attribute__((__interrupt__, auto_psv)) _T1Interrupt( void )
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358 /* Clear the timer interrupt. */
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361 if( xTaskIncrementTick() != pdFALSE )
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projects / freertos / blob