2 FreeRTOS V8.2.0rc1 - 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 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 >>! NOTE: The modification to the GPL is included to allow you to !<<
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14 >>! distribute a combined work that includes FreeRTOS without being !<<
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15 >>! obliged to provide the source code for proprietary components !<<
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16 >>! outside of the FreeRTOS kernel. !<<
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18 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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19 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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20 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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21 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * Having a problem? Start by reading the FAQ "My application does *
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28 * not run, what could be wrong?". Have you defined configASSERT()? *
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30 * http://www.FreeRTOS.org/FAQHelp.html *
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32 ***************************************************************************
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34 ***************************************************************************
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36 * FreeRTOS provides completely free yet professionally developed, *
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37 * robust, strictly quality controlled, supported, and cross *
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38 * platform software that is more than just the market leader, it *
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39 * is the industry's de facto standard. *
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41 * Help yourself get started quickly while simultaneously helping *
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42 * to support the FreeRTOS project by purchasing a FreeRTOS *
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43 * tutorial book, reference manual, or both: *
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44 * http://www.FreeRTOS.org/Documentation *
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46 ***************************************************************************
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48 ***************************************************************************
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50 * Investing in training allows your team to be as productive as *
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51 * possible as early as possible, lowering your overall development *
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52 * cost, and enabling you to bring a more robust product to market *
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53 * earlier than would otherwise be possible. Richard Barry is both *
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54 * the architect and key author of FreeRTOS, and so also the world's *
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55 * leading authority on what is the world's most popular real time *
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56 * kernel for deeply embedded MCU designs. Obtaining your training *
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57 * from Richard ensures your team will gain directly from his in-depth *
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58 * product knowledge and years of usage experience. Contact Real Time *
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59 * Engineers Ltd to enquire about the FreeRTOS Masterclass, presented *
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60 * by Richard Barry: http://www.FreeRTOS.org/contact
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62 ***************************************************************************
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64 ***************************************************************************
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66 * You are receiving this top quality software for free. Please play *
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67 * fair and reciprocate by reporting any suspected issues and *
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68 * participating in the community forum: *
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69 * http://www.FreeRTOS.org/support *
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73 ***************************************************************************
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75 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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76 license and Real Time Engineers Ltd. contact details.
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78 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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79 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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80 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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82 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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83 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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85 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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86 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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87 licenses offer ticketed support, indemnification and commercial middleware.
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89 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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90 engineered and independently SIL3 certified version for use in safety and
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91 mission critical applications that require provable dependability.
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96 /* High speed timer test as described in main.c. */
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98 /* Scheduler includes. */
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99 #include "FreeRTOS.h"
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101 /* Library includes. */
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102 #include "stm32f10x_lib.h"
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103 #include "stm32f10x_tim.h"
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104 #include "stm32f10x_map.h"
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106 /* The set frequency of the interrupt. Deviations from this are measured as
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108 #define timerINTERRUPT_FREQUENCY ( ( unsigned short ) 20000 )
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110 /* The expected time between each of the timer interrupts - if the jitter was
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112 #define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
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114 /* The highest available interrupt priority. */
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115 #define timerHIGHEST_PRIORITY ( 0 )
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117 /* Misc defines. */
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118 #define timerMAX_32BIT_VALUE ( 0xffffffffUL )
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119 #define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) )
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121 /* The number of interrupts to pass before we start looking at the jitter. */
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122 #define timerSETTLE_TIME 5
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124 /*-----------------------------------------------------------*/
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127 * Configures the two timers used to perform the test.
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129 void vSetupHighFrequencyTimer( void );
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131 /* Stores the value of the maximum recorded jitter between interrupts. */
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132 volatile unsigned short usMaxJitter = 0;
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134 /* Variable that counts at 20KHz to provide the time base for the run time
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136 unsigned long ulRunTimeStatsClock = 0UL;
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138 /*-----------------------------------------------------------*/
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140 void vSetupHighFrequencyTimer( void )
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142 unsigned long ulFrequency;
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143 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
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144 NVIC_InitTypeDef NVIC_InitStructure;
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147 /* Enable timer clocks */
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148 RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM2, ENABLE );
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149 RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM3, ENABLE );
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151 /* Initialise data. */
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152 TIM_DeInit( TIM2 );
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153 TIM_DeInit( TIM3 );
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154 TIM_TimeBaseStructInit( &TIM_TimeBaseStructure );
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156 /* Time base configuration for timer 2 - which generates the interrupts. */
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157 ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
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158 TIM_TimeBaseStructure.TIM_Period = ( unsigned short ) ( ulFrequency & 0xffffUL );
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159 TIM_TimeBaseStructure.TIM_Prescaler = 0x0;
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160 TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
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161 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
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162 TIM_TimeBaseInit( TIM2, &TIM_TimeBaseStructure );
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163 TIM_ARRPreloadConfig( TIM2, ENABLE );
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166 /* Configuration for timer 3 which is used as a high resolution time
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168 TIM_TimeBaseStructure.TIM_Period = ( unsigned short ) 0xffff;
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169 TIM_TimeBaseInit( TIM3, &TIM_TimeBaseStructure );
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170 TIM_ARRPreloadConfig( TIM3, ENABLE );
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172 /* Enable TIM2 IT. TIM3 does not generate an interrupt. */
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173 NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQChannel;
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174 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
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175 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = timerHIGHEST_PRIORITY;
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176 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
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177 NVIC_Init( &NVIC_InitStructure );
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178 TIM_ITConfig( TIM2, TIM_IT_Update, ENABLE );
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180 /* Finally, enable both timers. */
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181 TIM_Cmd( TIM2, ENABLE );
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182 TIM_Cmd( TIM3, ENABLE );
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184 /*-----------------------------------------------------------*/
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186 void TIM2_IRQHandler( void )
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188 static unsigned short usLastCount = 0, usSettleCount = 0, usMaxDifference = 0;
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189 unsigned short usThisCount, usDifference;
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191 /* Capture the free running timer 3 value as we enter the interrupt. */
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192 usThisCount = TIM3->CNT;
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194 if( usSettleCount >= timerSETTLE_TIME )
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196 /* What is the difference between the timer value in this interrupt
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197 and the value from the last interrupt. */
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198 usDifference = usThisCount - usLastCount;
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200 /* Store the difference in the timer values if it is larger than the
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201 currently stored largest value. The difference over and above the
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202 expected difference will give the 'jitter' in the processing of these
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204 if( usDifference > usMaxDifference )
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206 usMaxDifference = usDifference;
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207 usMaxJitter = usMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
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212 /* Don't bother storing any values for the first couple of
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217 /* Remember what the timer value was this time through, so we can calculate
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218 the difference the next time through. */
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219 usLastCount = usThisCount;
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221 /* Keep a count of the number of interrupts as a time base for the run time
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222 stats collection. */
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223 ulRunTimeStatsClock++;
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225 TIM_ClearITPendingBit( TIM2, TIM_IT_Update );
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