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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75 /*-----------------------------------------------------------
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76 * Implementation of functions defined in portable.h for the PIC32MX port.
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77 *----------------------------------------------------------*/
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80 #error This port is designed to work with XC32. Please update your C compiler version.
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83 /* Scheduler include files. */
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84 #include "FreeRTOS.h"
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87 /* Hardware specifics. */
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88 #define portTIMER_PRESCALE 8
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89 #define portPRESCALE_BITS 1
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91 /* Bits within various registers. */
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92 #define portIE_BIT ( 0x00000001 )
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93 #define portEXL_BIT ( 0x00000002 )
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95 /* Bits within the CAUSE register. */
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96 #define portCORE_SW_0 ( 0x00000100 )
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97 #define portCORE_SW_1 ( 0x00000200 )
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99 /* The EXL bit is set to ensure interrupts do not occur while the context of
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100 the first task is being restored. */
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101 #define portINITIAL_SR ( portIE_BIT | portEXL_BIT )
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103 #ifndef configTICK_INTERRUPT_VECTOR
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104 #define configTICK_INTERRUPT_VECTOR _TIMER_1_VECTOR
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107 /* Records the interrupt nesting depth. This starts at one as it will be
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108 decremented to 0 when the first task starts. */
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109 volatile unsigned portBASE_TYPE uxInterruptNesting = 0x01;
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111 /* Stores the task stack pointer when a switch is made to use the system stack. */
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112 unsigned portBASE_TYPE uxSavedTaskStackPointer = 0;
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114 /* The stack used by interrupt service routines that cause a context switch. */
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115 portSTACK_TYPE xISRStack[ configISR_STACK_SIZE ] = { 0 };
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117 /* The top of stack value ensures there is enough space to store 6 registers on
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118 the callers stack, as some functions seem to want to do this. */
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119 const portSTACK_TYPE * const xISRStackTop = &( xISRStack[ configISR_STACK_SIZE - 7 ] );
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122 * Place the prototype here to ensure the interrupt vector is correctly installed.
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123 * Note that because the interrupt is written in assembly, the IPL setting in the
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124 * following line of code has no effect. The interrupt priority is set by the
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125 * call to ConfigIntTimer1() in vApplicationSetupTickTimerInterrupt().
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127 extern void __attribute__( (interrupt(ipl1), vector( configTICK_INTERRUPT_VECTOR ))) vPortTickInterruptHandler( void );
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130 * The software interrupt handler that performs the yield. Note that, because
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131 * the interrupt is written in assembly, the IPL setting in the following line of
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132 * code has no effect. The interrupt priority is set by the call to
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133 * mConfigIntCoreSW0() in xPortStartScheduler().
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135 void __attribute__( (interrupt(ipl1), vector(_CORE_SOFTWARE_0_VECTOR))) vPortYieldISR( void );
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137 /*-----------------------------------------------------------*/
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140 * See header file for description.
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142 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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144 /* Ensure byte alignment is maintained when leaving this function. */
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147 *pxTopOfStack = (portSTACK_TYPE) 0xDEADBEEF;
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150 *pxTopOfStack = (portSTACK_TYPE) 0x12345678; /* Word to which the stack pointer will be left pointing after context restore. */
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153 *pxTopOfStack = (portSTACK_TYPE) _CP0_GET_CAUSE();
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156 *pxTopOfStack = (portSTACK_TYPE) portINITIAL_SR; /* CP0_STATUS */
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159 *pxTopOfStack = (portSTACK_TYPE) pxCode; /* CP0_EPC */
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162 *pxTopOfStack = (portSTACK_TYPE) NULL; /* ra */
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163 pxTopOfStack -= 15;
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165 *pxTopOfStack = (portSTACK_TYPE) pvParameters; /* Parameters to pass in */
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166 pxTopOfStack -= 14;
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168 *pxTopOfStack = (portSTACK_TYPE) 0x00000000; /* critical nesting level - no longer used. */
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171 return pxTopOfStack;
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173 /*-----------------------------------------------------------*/
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176 * Setup a timer for a regular tick. This function uses peripheral timer 1.
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177 * The function is declared weak so an application writer can use a different
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178 * timer by redefining this implementation. If a different timer is used then
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179 * configTICK_INTERRUPT_VECTOR must also be defined in FreeRTOSConfig.h to
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180 * ensure the RTOS provided tick interrupt handler is installed on the correct
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181 * vector number. When Timer 1 is used the vector number is defined as
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184 __attribute__(( weak )) void vApplicationSetupTickTimerInterrupt( void )
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186 const unsigned long ulCompareMatch = ( (configPERIPHERAL_CLOCK_HZ / portTIMER_PRESCALE) / configTICK_RATE_HZ ) - 1;
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189 T1CONbits.TCKPS = portPRESCALE_BITS;
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190 PR1 = ulCompareMatch;
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191 IPC1bits.T1IP = configKERNEL_INTERRUPT_PRIORITY;
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193 /* Clear the interrupt as a starting condition. */
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196 /* Enable the interrupt. */
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199 /* Start the timer. */
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202 /*-----------------------------------------------------------*/
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204 void vPortEndScheduler(void)
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206 /* It is unlikely that the scheduler for the PIC port will get stopped
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207 once running. If required disable the tick interrupt here, then return
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208 to xPortStartScheduler(). */
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211 /*-----------------------------------------------------------*/
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213 portBASE_TYPE xPortStartScheduler( void )
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215 extern void vPortStartFirstTask( void );
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216 extern void *pxCurrentTCB;
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218 /* Clear the software interrupt flag. */
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219 IFS0CLR = _IFS0_CS0IF_MASK;
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221 /* Set software timer priority. */
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222 IPC0CLR = _IPC0_CS0IP_MASK;
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223 IPC0SET = ( configKERNEL_INTERRUPT_PRIORITY << _IPC0_CS0IP_POSITION );
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225 /* Enable software interrupt. */
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226 IEC0CLR = _IEC0_CS0IE_MASK;
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227 IEC0SET = 1 << _IEC0_CS0IE_POSITION;
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229 /* Setup the timer to generate the tick. Interrupts will have been
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230 disabled by the time we get here. */
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231 vApplicationSetupTickTimerInterrupt();
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233 /* Kick off the highest priority task that has been created so far.
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234 Its stack location is loaded into uxSavedTaskStackPointer. */
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235 uxSavedTaskStackPointer = *( unsigned portBASE_TYPE * ) pxCurrentTCB;
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236 vPortStartFirstTask();
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238 /* Should never get here as the tasks will now be executing. */
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241 /*-----------------------------------------------------------*/
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243 void vPortIncrementTick( void )
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245 unsigned portBASE_TYPE uxSavedStatus;
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247 uxSavedStatus = uxPortSetInterruptMaskFromISR();
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249 if( xTaskIncrementTick() != pdFALSE )
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251 /* Pend a context switch. */
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252 _CP0_BIS_CAUSE( portCORE_SW_0 );
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255 vPortClearInterruptMaskFromISR( uxSavedStatus );
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257 /* Clear timer 1 interrupt. */
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258 IFS0CLR = _IFS0_T1IF_MASK;
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260 /*-----------------------------------------------------------*/
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262 unsigned portBASE_TYPE uxPortSetInterruptMaskFromISR( void )
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264 unsigned portBASE_TYPE uxSavedStatusRegister;
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266 asm volatile ( "di" );
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267 uxSavedStatusRegister = _CP0_GET_STATUS() | 0x01;
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268 /* This clears the IPL bits, then sets them to
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269 configMAX_SYSCALL_INTERRUPT_PRIORITY. This function should not be called
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270 from an interrupt that has a priority above
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271 configMAX_SYSCALL_INTERRUPT_PRIORITY so, when used correctly, the action
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272 can only result in the IPL being unchanged or raised, and therefore never
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274 _CP0_SET_STATUS( ( ( uxSavedStatusRegister & ( ~portALL_IPL_BITS ) ) ) | ( configMAX_SYSCALL_INTERRUPT_PRIORITY << portIPL_SHIFT ) );
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276 return uxSavedStatusRegister;
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278 /*-----------------------------------------------------------*/
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280 void vPortClearInterruptMaskFromISR( unsigned portBASE_TYPE uxSavedStatusRegister )
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282 _CP0_SET_STATUS( uxSavedStatusRegister );
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284 /*-----------------------------------------------------------*/
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