2 FreeRTOS.org V4.3.1 - Copyright (C) 2003-2007 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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31 Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along
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32 with commercial development and support options.
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33 ***************************************************************************
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36 /* High speed timer test as described in main.c. */
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38 /* Scheduler includes. */
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39 #include "FreeRTOS.h"
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41 /* Library includes. */
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42 #include "stm32f10x_lib.h"
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43 #include "stm32f10x_tim.h"
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44 #include "stm32f10x_map.h"
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46 /* The set frequency of the interrupt. Deviations from this are measured as
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48 #define timerINTERRUPT_FREQUENCY ( ( unsigned portSHORT ) 20000 )
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50 /* The expected time between each of the timer interrupts - if the jitter was
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52 #define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
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54 /* The highest available interrupt priority. */
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55 #define timerHIGHEST_PRIORITY ( 0 )
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58 #define timerMAX_32BIT_VALUE ( 0xffffffffUL )
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59 #define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) )
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61 /* The number of interrupts to pass before we start looking at the jitter. */
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62 #define timerSETTLE_TIME 5
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64 /*-----------------------------------------------------------*/
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67 * Configures the two timers used to perform the test.
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69 void vSetupTimerTest( void );
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71 /* Interrupt handler in which the jitter is measured. */
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72 void vTimer2IntHandler( void );
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74 /* Stores the value of the maximum recorded jitter between interrupts. */
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75 volatile unsigned portSHORT usMaxJitter = 0;
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77 /*-----------------------------------------------------------*/
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79 void vSetupTimerTest( void )
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81 unsigned long ulFrequency;
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82 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
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83 NVIC_InitTypeDef NVIC_InitStructure;
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86 /* Enable timer clocks */
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87 RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM2, ENABLE );
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88 RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM3, ENABLE );
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90 /* Initialise data. */
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93 TIM_TimeBaseStructInit( &TIM_TimeBaseStructure );
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95 /* Time base configuration for timer 2 - which generates the interrupts. */
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96 ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
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97 TIM_TimeBaseStructure.TIM_Period = ( unsigned portSHORT ) ( ulFrequency & 0xffffUL );
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98 TIM_TimeBaseStructure.TIM_Prescaler = 0x0;
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99 TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
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100 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
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101 TIM_TimeBaseInit( TIM2, &TIM_TimeBaseStructure );
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102 TIM_ARRPreloadConfig( TIM2, ENABLE );
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105 /* Configuration for timer 3 which is used as a high resolution time
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107 TIM_TimeBaseStructure.TIM_Period = ( unsigned portSHORT ) 0xffff;
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108 TIM_TimeBaseInit( TIM3, &TIM_TimeBaseStructure );
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109 TIM_ARRPreloadConfig( TIM3, ENABLE );
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111 /* Enable TIM2 IT. TIM3 does not generate an interrupt. */
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112 NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQChannel;
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113 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
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114 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = timerHIGHEST_PRIORITY;
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115 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
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116 NVIC_Init( &NVIC_InitStructure );
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117 TIM_ITConfig( TIM2, TIM_IT_Update, ENABLE );
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119 /* Finally, enable both timers. */
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120 TIM_Cmd( TIM2, ENABLE );
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121 TIM_Cmd( TIM3, ENABLE );
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123 /*-----------------------------------------------------------*/
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125 void vTimer2IntHandler( void )
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127 static unsigned portSHORT usLastCount = 0, usSettleCount = 0, usMaxDifference = 0;
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128 unsigned portSHORT usThisCount, usDifference;
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130 /* Capture the free running timer 3 value as we enter the interrupt. */
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131 usThisCount = TIM3->CNT;
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133 if( usSettleCount >= timerSETTLE_TIME )
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135 /* What is the difference between the timer value in this interrupt
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136 and the value from the last interrupt. */
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137 usDifference = usThisCount - usLastCount;
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139 /* Store the difference in the timer values if it is larger than the
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140 currently stored largest value. The difference over and above the
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141 expected difference will give the 'jitter' in the processing of these
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143 if( usDifference > usMaxDifference )
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145 usMaxDifference = usDifference;
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146 usMaxJitter = usMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
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151 /* Don't bother storing any values for the first couple of
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156 /* Remember what the timer value was this time through, so we can calculate
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157 the difference the next time through. */
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158 usLastCount = usThisCount;
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160 TIM_ClearITPendingBit( TIM2, TIM_IT_Update );
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