2 FreeRTOS V8.2.0 - Copyright (C) 2015 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 "hw_ints.h"
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77 #include "hw_memmap.h"
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78 #include "hw_types.h"
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79 #include "interrupt.h"
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81 #include "lmi_timer.h"
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82 #include "hw_timer.h"
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84 /* The set frequency of the interrupt. Deviations from this are measured as
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86 #define timerINTERRUPT_FREQUENCY ( 20000UL )
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88 /* The expected time between each of the timer interrupts - if the jitter was
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90 #define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
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92 /* The highest available interrupt priority. */
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93 #define timerHIGHEST_PRIORITY ( 0 )
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96 #define timerMAX_32BIT_VALUE ( 0xffffffffUL )
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97 #define timerTIMER_1_COUNT_VALUE ( * ( ( volatile unsigned long * ) ( ( unsigned long ) TIMER1_BASE + 0x48UL ) ) )
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99 /*-----------------------------------------------------------*/
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101 /* Interrupt handler in which the jitter is measured. */
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102 void Timer0IntHandler( void );
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104 /* Stores the value of the maximum recorded jitter between interrupts. */
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105 volatile unsigned long ulMaxJitter = 0;
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107 /*-----------------------------------------------------------*/
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109 void vSetupHighFrequencyTimer( void )
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111 unsigned long ulFrequency;
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113 /* Timer zero is used to generate the interrupts, and timer 1 is used
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114 to measure the jitter. */
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115 SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER0 );
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116 SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER1 );
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117 TimerConfigure( TIMER0_BASE, TIMER_CFG_32_BIT_PER );
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118 TimerConfigure( TIMER1_BASE, TIMER_CFG_32_BIT_PER );
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120 /* Set the timer interrupt to be above the kernel - highest. */
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121 IntPrioritySet( INT_TIMER0A, timerHIGHEST_PRIORITY );
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123 /* Just used to measure time. */
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124 TimerLoadSet(TIMER1_BASE, TIMER_A, timerMAX_32BIT_VALUE );
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126 /* Ensure interrupts do not start until the scheduler is running. */
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127 portDISABLE_INTERRUPTS();
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129 /* The rate at which the timer will interrupt. */
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130 ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
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131 TimerLoadSet( TIMER0_BASE, TIMER_A, ulFrequency );
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132 IntEnable( INT_TIMER0A );
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133 TimerIntEnable( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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135 /* Enable both timers. */
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136 TimerEnable( TIMER0_BASE, TIMER_A );
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137 TimerEnable( TIMER1_BASE, TIMER_A );
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139 /*-----------------------------------------------------------*/
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141 void Timer0IntHandler( void )
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143 unsigned long ulDifference;
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144 volatile unsigned long ulCurrentCount;
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145 static unsigned long ulMaxDifference = 0, ulLastCount = 0;
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147 /* We use the timer 1 counter value to measure the clock cycles between
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148 the timer 0 interrupts. */
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149 ulCurrentCount = timerTIMER_1_COUNT_VALUE;
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151 TimerIntClear( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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153 if( ulCurrentCount < ulLastCount )
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155 /* How many times has timer 1 counted since the last interrupt? */
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156 ulDifference = ulLastCount - ulCurrentCount;
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158 /* Is this the largest difference we have measured yet? */
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159 if( ulDifference > ulMaxDifference )
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161 ulMaxDifference = ulDifference;
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162 ulMaxJitter = ulMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
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166 ulLastCount = ulCurrentCount;
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