2 FreeRTOS V9.0.0rc2 - Copyright (C) 2016 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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70 /* High speed timer test as described in main.c. */
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72 /* Scheduler includes. */
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73 #include "FreeRTOS.h"
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75 /* Library includes. */
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76 #include "stm32f10x_lib.h"
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77 #include "stm32f10x_tim.h"
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78 #include "stm32f10x_map.h"
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80 /* The set frequency of the interrupt. Deviations from this are measured as
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82 #define timerINTERRUPT_FREQUENCY ( ( unsigned short ) 20000 )
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84 /* The expected time between each of the timer interrupts - if the jitter was
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86 #define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
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88 /* The highest available interrupt priority. */
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89 #define timerHIGHEST_PRIORITY ( 0 )
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92 #define timerMAX_32BIT_VALUE ( 0xffffffffUL )
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93 #define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) )
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95 /* The number of interrupts to pass before we start looking at the jitter. */
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96 #define timerSETTLE_TIME 5
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98 /*-----------------------------------------------------------*/
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101 * Configures the two timers used to perform the test.
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103 void vSetupHighFrequencyTimer( void );
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105 /* Stores the value of the maximum recorded jitter between interrupts. */
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106 volatile unsigned short usMaxJitter = 0;
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108 /* Variable that counts at 20KHz to provide the time base for the run time
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110 unsigned long ulRunTimeStatsClock = 0UL;
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112 /*-----------------------------------------------------------*/
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114 void vSetupHighFrequencyTimer( void )
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116 unsigned long ulFrequency;
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117 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
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118 NVIC_InitTypeDef NVIC_InitStructure;
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121 /* Enable timer clocks */
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122 RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM2, ENABLE );
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123 RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM3, ENABLE );
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125 /* Initialise data. */
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126 TIM_DeInit( TIM2 );
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127 TIM_DeInit( TIM3 );
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128 TIM_TimeBaseStructInit( &TIM_TimeBaseStructure );
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130 /* Time base configuration for timer 2 - which generates the interrupts. */
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131 ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
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132 TIM_TimeBaseStructure.TIM_Period = ( unsigned short ) ( ulFrequency & 0xffffUL );
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133 TIM_TimeBaseStructure.TIM_Prescaler = 0x0;
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134 TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
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135 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
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136 TIM_TimeBaseInit( TIM2, &TIM_TimeBaseStructure );
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137 TIM_ARRPreloadConfig( TIM2, ENABLE );
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140 /* Configuration for timer 3 which is used as a high resolution time
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142 TIM_TimeBaseStructure.TIM_Period = ( unsigned short ) 0xffff;
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143 TIM_TimeBaseInit( TIM3, &TIM_TimeBaseStructure );
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144 TIM_ARRPreloadConfig( TIM3, ENABLE );
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146 /* Enable TIM2 IT. TIM3 does not generate an interrupt. */
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147 NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQChannel;
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148 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
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149 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = timerHIGHEST_PRIORITY;
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150 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
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151 NVIC_Init( &NVIC_InitStructure );
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152 TIM_ITConfig( TIM2, TIM_IT_Update, ENABLE );
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154 /* Finally, enable both timers. */
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155 TIM_Cmd( TIM2, ENABLE );
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156 TIM_Cmd( TIM3, ENABLE );
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158 /*-----------------------------------------------------------*/
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160 void TIM2_IRQHandler( void )
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162 static unsigned short usLastCount = 0, usSettleCount = 0, usMaxDifference = 0;
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163 unsigned short usThisCount, usDifference;
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165 /* Capture the free running timer 3 value as we enter the interrupt. */
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166 usThisCount = TIM3->CNT;
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168 if( usSettleCount >= timerSETTLE_TIME )
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170 /* What is the difference between the timer value in this interrupt
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171 and the value from the last interrupt. */
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172 usDifference = usThisCount - usLastCount;
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174 /* Store the difference in the timer values if it is larger than the
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175 currently stored largest value. The difference over and above the
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176 expected difference will give the 'jitter' in the processing of these
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178 if( usDifference > usMaxDifference )
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180 usMaxDifference = usDifference;
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181 usMaxJitter = usMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
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186 /* Don't bother storing any values for the first couple of
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191 /* Remember what the timer value was this time through, so we can calculate
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192 the difference the next time through. */
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193 usLastCount = usThisCount;
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195 /* Keep a count of the number of interrupts as a time base for the run time
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196 stats collection. */
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197 ulRunTimeStatsClock++;
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199 TIM_ClearITPendingBit( TIM2, TIM_IT_Update );
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