2 FreeRTOS V7.5.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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6 ***************************************************************************
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8 * FreeRTOS provides completely free yet professionally developed, *
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9 * robust, strictly quality controlled, supported, and cross *
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10 * platform software that has become a de facto standard. *
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12 * Help yourself get started quickly and support the FreeRTOS *
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13 * project by purchasing a FreeRTOS tutorial book, reference *
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14 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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18 ***************************************************************************
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20 This file is part of the FreeRTOS distribution.
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22 FreeRTOS is free software; you can redistribute it and/or modify it under
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23 the terms of the GNU General Public License (version 2) as published by the
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24 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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26 >>! NOTE: The modification to the GPL is included to allow you to distribute
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27 >>! a combined work that includes FreeRTOS without being obliged to provide
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28 >>! the source code for proprietary components outside of the FreeRTOS
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31 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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32 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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33 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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34 link: http://www.freertos.org/a00114.html
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38 ***************************************************************************
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40 * Having a problem? Start by reading the FAQ "My application does *
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41 * not run, what could be wrong?" *
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43 * http://www.FreeRTOS.org/FAQHelp.html *
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45 ***************************************************************************
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47 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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48 license and Real Time Engineers Ltd. contact details.
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50 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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51 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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52 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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54 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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55 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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56 licenses offer ticketed support, indemnification and middleware.
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58 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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59 engineered and independently SIL3 certified version for use in safety and
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60 mission critical applications that require provable dependability.
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65 /* High speed timer test as described in main.c. */
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67 /* Scheduler includes. */
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68 #include "FreeRTOS.h"
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70 /* Library includes. */
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71 #include "stm32f10x_lib.h"
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72 #include "stm32f10x_tim.h"
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73 #include "stm32f10x_map.h"
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75 /* The set frequency of the interrupt. Deviations from this are measured as
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77 #define timerINTERRUPT_FREQUENCY ( ( unsigned portSHORT ) 20000 )
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79 /* The expected time between each of the timer interrupts - if the jitter was
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81 #define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
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83 /* The highest available interrupt priority. */
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84 #define timerHIGHEST_PRIORITY ( 0 )
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87 #define timerMAX_32BIT_VALUE ( 0xffffffffUL )
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88 #define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) )
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90 /* The number of interrupts to pass before we start looking at the jitter. */
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91 #define timerSETTLE_TIME 5
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93 /*-----------------------------------------------------------*/
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96 * Configures the two timers used to perform the test.
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98 void vSetupTimerTest( void );
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100 /* Interrupt handler in which the jitter is measured. */
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101 void vTimer2IntHandler( void );
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103 /* Stores the value of the maximum recorded jitter between interrupts. */
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104 volatile unsigned portSHORT usMaxJitter = 0;
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106 /*-----------------------------------------------------------*/
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108 void vSetupTimerTest( void )
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110 unsigned long ulFrequency;
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111 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
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112 NVIC_InitTypeDef NVIC_InitStructure;
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115 /* Enable timer clocks */
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116 RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM2, ENABLE );
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117 RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM3, ENABLE );
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119 /* Initialise data. */
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120 TIM_DeInit( TIM2 );
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121 TIM_DeInit( TIM3 );
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122 TIM_TimeBaseStructInit( &TIM_TimeBaseStructure );
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124 /* Time base configuration for timer 2 - which generates the interrupts. */
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125 ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
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126 TIM_TimeBaseStructure.TIM_Period = ( unsigned portSHORT ) ( ulFrequency & 0xffffUL );
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127 TIM_TimeBaseStructure.TIM_Prescaler = 0x0;
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128 TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
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129 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
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130 TIM_TimeBaseInit( TIM2, &TIM_TimeBaseStructure );
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131 TIM_ARRPreloadConfig( TIM2, ENABLE );
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134 /* Configuration for timer 3 which is used as a high resolution time
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136 TIM_TimeBaseStructure.TIM_Period = ( unsigned portSHORT ) 0xffff;
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137 TIM_TimeBaseInit( TIM3, &TIM_TimeBaseStructure );
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138 TIM_ARRPreloadConfig( TIM3, ENABLE );
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140 /* Enable TIM2 IT. TIM3 does not generate an interrupt. */
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141 NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQChannel;
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142 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
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143 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = timerHIGHEST_PRIORITY;
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144 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
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145 NVIC_Init( &NVIC_InitStructure );
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146 TIM_ITConfig( TIM2, TIM_IT_Update, ENABLE );
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148 /* Finally, enable both timers. */
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149 TIM_Cmd( TIM2, ENABLE );
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150 TIM_Cmd( TIM3, ENABLE );
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152 /*-----------------------------------------------------------*/
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154 void vTimer2IntHandler( void )
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156 static unsigned portSHORT usLastCount = 0, usSettleCount = 0, usMaxDifference = 0;
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157 unsigned portSHORT usThisCount, usDifference;
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159 /* Capture the free running timer 3 value as we enter the interrupt. */
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160 usThisCount = TIM3->CNT;
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162 if( usSettleCount >= timerSETTLE_TIME )
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164 /* What is the difference between the timer value in this interrupt
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165 and the value from the last interrupt. */
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166 usDifference = usThisCount - usLastCount;
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168 /* Store the difference in the timer values if it is larger than the
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169 currently stored largest value. The difference over and above the
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170 expected difference will give the 'jitter' in the processing of these
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172 if( usDifference > usMaxDifference )
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174 usMaxDifference = usDifference;
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175 usMaxJitter = usMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
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180 /* Don't bother storing any values for the first couple of
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185 /* Remember what the timer value was this time through, so we can calculate
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186 the difference the next time through. */
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187 usLastCount = usThisCount;
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189 TIM_ClearITPendingBit( TIM2, TIM_IT_Update );
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