2 FreeRTOS V8.2.2 - Copyright (C) 2015 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 This file is part of the FreeRTOS distribution.
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9 FreeRTOS is free software; you can redistribute it and/or modify it under
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10 the terms of the GNU General Public License (version 2) as published by the
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11 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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13 ***************************************************************************
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14 >>! NOTE: The modification to the GPL is included to allow you to !<<
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15 >>! distribute a combined work that includes FreeRTOS without being !<<
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16 >>! obliged to provide the source code for proprietary components !<<
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17 >>! outside of the FreeRTOS kernel. !<<
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18 ***************************************************************************
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20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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22 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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23 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * FreeRTOS provides completely free yet professionally developed, *
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28 * robust, strictly quality controlled, supported, and cross *
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29 * platform software that is more than just the market leader, it *
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30 * is the industry's de facto standard. *
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32 * Help yourself get started quickly while simultaneously helping *
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33 * to support the FreeRTOS project by purchasing a FreeRTOS *
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34 * tutorial book, reference manual, or both: *
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35 * http://www.FreeRTOS.org/Documentation *
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37 ***************************************************************************
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39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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40 the FAQ page "My application does not run, what could be wrong?". Have you
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41 defined configASSERT()?
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43 http://www.FreeRTOS.org/support - In return for receiving this top quality
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44 embedded software for free we request you assist our global community by
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45 participating in the support forum.
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47 http://www.FreeRTOS.org/training - Investing in training allows your team to
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48 be as productive as possible as early as possible. Now you can receive
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49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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50 Ltd, and the world's leading authority on the world's leading RTOS.
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52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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54 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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61 licenses offer ticketed support, indemnification and commercial middleware.
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63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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64 engineered and independently SIL3 certified version for use in safety and
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65 mission critical applications that require provable dependability.
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71 * High frequency timer test as described in main.c.
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74 /* Scheduler includes. */
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75 #include "FreeRTOS.h"
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77 /* The set frequency of the interrupt. Deviations from this are measured as
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79 #define timerINTERRUPT_FREQUENCY ( 20000UL )
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81 /* The expected time between each of the timer interrupts - if the jitter was
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83 #define timerEXPECTED_DIFFERENCE_VALUE ( ( unsigned short ) ( ( configPERIPHERAL_CLOCK_HZ / 8UL ) / timerINTERRUPT_FREQUENCY ) )
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85 /* The highest available interrupt priority. */
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86 #define timerHIGHEST_PRIORITY ( 15 )
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89 #define timerTIMER_3_COUNT_VALUE ( *( ( unsigned short * ) 0x8801a ) ) /*( CMT3.CMCNT )*/
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91 /*-----------------------------------------------------------*/
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93 /* Interrupt handler in which the jitter is measured. */
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94 static void prvTimer2IntHandler( void );
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96 /* Stores the value of the maximum recorded jitter between interrupts. This is
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97 displayed on one of the served web pages. */
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98 volatile unsigned short usMaxJitter = 0;
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100 /* Counts the number of high frequency interrupts - used to generate the run
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102 volatile unsigned long ulHighFrequencyTickCount = 0UL;
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104 /*-----------------------------------------------------------*/
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106 void vSetupHighFrequencyTimer( void )
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108 /* Timer CMT2 is used to generate the interrupts, and CMT3 is used
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109 to measure the jitter. */
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111 /* Enable compare match timer 2 and 3. */
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115 /* Interrupt on compare match. */
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116 CMT2.CMCR.BIT.CMIE = 1;
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118 /* Set the compare match value. */
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119 CMT2.CMCOR = ( unsigned short ) ( ( ( configPERIPHERAL_CLOCK_HZ / timerINTERRUPT_FREQUENCY ) -1 ) / 8 );
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121 /* Divide the PCLK by 8. */
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122 CMT2.CMCR.BIT.CKS = 0;
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123 CMT3.CMCR.BIT.CKS = 0;
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125 /* Enable the interrupt... */
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126 _IEN( _CMT2_CMI2 ) = 1;
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128 /* ...and set its priority to the maximum possible, this is above the priority
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129 set by configMAX_SYSCALL_INTERRUPT_PRIORITY so will nest. */
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130 _IPR( _CMT2_CMI2 ) = timerHIGHEST_PRIORITY;
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132 /* Start the timers. */
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133 CMT.CMSTR1.BIT.STR2 = 1;
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134 CMT.CMSTR1.BIT.STR3 = 1;
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136 /*-----------------------------------------------------------*/
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138 #pragma interrupt ( prvTimer2IntHandler( vect = _VECT( _CMT2_CMI2 ), enable ) )
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139 static void prvTimer2IntHandler( void )
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141 volatile unsigned short usCurrentCount;
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142 static unsigned short usMaxCount = 0;
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143 static unsigned long ulErrorCount = 0UL;
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145 /* We use the timer 1 counter value to measure the clock cycles between
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146 the timer 0 interrupts. First stop the clock. */
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147 CMT.CMSTR1.BIT.STR3 = 0;
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150 usCurrentCount = timerTIMER_3_COUNT_VALUE;
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152 /* Is this the largest count we have measured yet? */
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153 if( usCurrentCount > usMaxCount )
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155 if( usCurrentCount > timerEXPECTED_DIFFERENCE_VALUE )
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157 usMaxJitter = usCurrentCount - timerEXPECTED_DIFFERENCE_VALUE;
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161 /* This should not happen! */
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165 usMaxCount = usCurrentCount;
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168 /* Used to generate the run time stats. */
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169 ulHighFrequencyTickCount++;
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171 /* Clear the timer. */
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172 timerTIMER_3_COUNT_VALUE = 0;
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174 /* Then start the clock again. */
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175 CMT.CMSTR1.BIT.STR3 = 1;
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