2 FreeRTOS V8.1.0 - Copyright (C) 2014 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 ***************************************************************************
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9 * FreeRTOS provides completely free yet professionally developed, *
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10 * robust, strictly quality controlled, supported, and cross *
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11 * platform software that has become a de facto standard. *
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13 * Help yourself get started quickly and support the FreeRTOS *
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14 * project by purchasing a FreeRTOS tutorial book, reference *
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15 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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19 ***************************************************************************
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21 This file is part of the FreeRTOS distribution.
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23 FreeRTOS is free software; you can redistribute it and/or modify it under
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24 the terms of the GNU General Public License (version 2) as published by the
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25 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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27 >>! NOTE: The modification to the GPL is included to allow you to !<<
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28 >>! distribute a combined work that includes FreeRTOS without being !<<
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29 >>! obliged to provide the source code for proprietary components !<<
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30 >>! outside of the FreeRTOS kernel. !<<
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32 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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33 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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34 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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35 link: http://www.freertos.org/a00114.html
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39 ***************************************************************************
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41 * Having a problem? Start by reading the FAQ "My application does *
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42 * not run, what could be wrong?" *
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44 * http://www.FreeRTOS.org/FAQHelp.html *
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46 ***************************************************************************
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48 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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49 license and Real Time Engineers Ltd. contact details.
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51 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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52 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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53 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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55 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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56 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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57 licenses offer ticketed support, indemnification and middleware.
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59 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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60 engineered and independently SIL3 certified version for use in safety and
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61 mission critical applications that require provable dependability.
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66 /* High speed timer test as described in main.c. */
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68 /* Scheduler includes. */
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69 #include "FreeRTOS.h"
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71 /* Library includes. */
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72 #include "stm32f10x_lib.h"
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73 #include "stm32f10x_tim.h"
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74 #include "stm32f10x_map.h"
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76 /* The set frequency of the interrupt. Deviations from this are measured as
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78 #define timerINTERRUPT_FREQUENCY ( ( unsigned short ) 20000 )
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80 /* The expected time between each of the timer interrupts - if the jitter was
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82 #define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
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84 /* The highest available interrupt priority. */
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85 #define timerHIGHEST_PRIORITY ( 0 )
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88 #define timerMAX_32BIT_VALUE ( 0xffffffffUL )
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89 #define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) )
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91 /* The number of interrupts to pass before we start looking at the jitter. */
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92 #define timerSETTLE_TIME 5
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94 /*-----------------------------------------------------------*/
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97 * Configures the two timers used to perform the test.
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99 void vSetupTimerTest( void );
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101 /* Interrupt handler in which the jitter is measured. */
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102 void vTimer2IntHandler( void );
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104 /* Stores the value of the maximum recorded jitter between interrupts. */
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105 volatile unsigned short usMaxJitter = 0;
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107 /*-----------------------------------------------------------*/
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109 void vSetupTimerTest( void )
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111 unsigned long ulFrequency;
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112 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
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113 NVIC_InitTypeDef NVIC_InitStructure;
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116 /* Enable timer clocks */
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117 RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM2, ENABLE );
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118 RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM3, ENABLE );
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120 /* Initialise data. */
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121 TIM_DeInit( TIM2 );
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122 TIM_DeInit( TIM3 );
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123 TIM_TimeBaseStructInit( &TIM_TimeBaseStructure );
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125 /* Time base configuration for timer 2 - which generates the interrupts. */
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126 ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
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127 TIM_TimeBaseStructure.TIM_Period = ( unsigned short ) ( ulFrequency & 0xffffUL );
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128 TIM_TimeBaseStructure.TIM_Prescaler = 0x0;
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129 TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
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130 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
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131 TIM_TimeBaseInit( TIM2, &TIM_TimeBaseStructure );
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132 TIM_ARRPreloadConfig( TIM2, ENABLE );
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135 /* Configuration for timer 3 which is used as a high resolution time
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137 TIM_TimeBaseStructure.TIM_Period = ( unsigned short ) 0xffff;
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138 TIM_TimeBaseInit( TIM3, &TIM_TimeBaseStructure );
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139 TIM_ARRPreloadConfig( TIM3, ENABLE );
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141 /* Enable TIM2 IT. TIM3 does not generate an interrupt. */
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142 NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQChannel;
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143 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
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144 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = timerHIGHEST_PRIORITY;
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145 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
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146 NVIC_Init( &NVIC_InitStructure );
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147 TIM_ITConfig( TIM2, TIM_IT_Update, ENABLE );
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149 /* Finally, enable both timers. */
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150 TIM_Cmd( TIM2, ENABLE );
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151 TIM_Cmd( TIM3, ENABLE );
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153 /*-----------------------------------------------------------*/
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155 void vTimer2IntHandler( void )
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157 static unsigned short usLastCount = 0, usSettleCount = 0, usMaxDifference = 0;
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158 unsigned short usThisCount, usDifference;
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160 /* Capture the free running timer 3 value as we enter the interrupt. */
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161 usThisCount = TIM3->CNT;
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163 if( usSettleCount >= timerSETTLE_TIME )
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165 /* What is the difference between the timer value in this interrupt
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166 and the value from the last interrupt. */
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167 usDifference = usThisCount - usLastCount;
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169 /* Store the difference in the timer values if it is larger than the
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170 currently stored largest value. The difference over and above the
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171 expected difference will give the 'jitter' in the processing of these
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173 if( usDifference > usMaxDifference )
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175 usMaxDifference = usDifference;
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176 usMaxJitter = usMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
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181 /* Don't bother storing any values for the first couple of
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186 /* Remember what the timer value was this time through, so we can calculate
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187 the difference the next time through. */
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188 usLastCount = usThisCount;
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190 TIM_ClearITPendingBit( TIM2, TIM_IT_Update );
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