2 FreeRTOS V8.1.2 - 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 "hw_ints.h"
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73 #include "hw_memmap.h"
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74 #include "hw_types.h"
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75 #include "interrupt.h"
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77 #include "lmi_timer.h"
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79 /* The set frequency of the interrupt. Deviations from this are measured as
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81 #define timerINTERRUPT_FREQUENCY ( 20000UL )
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83 /* The expected time between each of the timer interrupts - if the jitter was
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85 #define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
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87 /* The highest available interrupt priority. */
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88 #define timerHIGHEST_PRIORITY ( 0 )
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91 #define timerMAX_32BIT_VALUE ( 0xffffffffUL )
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92 #define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) )
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94 /*-----------------------------------------------------------*/
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96 /* Interrupt handler in which the jitter is measured. */
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97 void Timer0IntHandler( void );
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99 /* Stores the value of the maximum recorded jitter between interrupts. */
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100 volatile unsigned long ulMaxJitter = 0UL;
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102 /* Counts the total number of times that the high frequency timer has 'ticked'.
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103 This value is used by the run time stats function to work out what percentage
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104 of CPU time each task is taking. */
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105 volatile unsigned long ulHighFrequencyTimerTicks = 0UL;
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106 /*-----------------------------------------------------------*/
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108 void vSetupHighFrequencyTimer( void )
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110 unsigned long ulFrequency;
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112 /* Timer zero is used to generate the interrupts, and timer 1 is used
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113 to measure the jitter. */
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114 SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER0 );
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115 SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER1 );
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116 TimerConfigure( TIMER0_BASE, TIMER_CFG_32_BIT_PER );
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117 TimerConfigure( TIMER1_BASE, TIMER_CFG_32_BIT_PER );
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119 /* Set the timer interrupt to be above the kernel - highest. */
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120 IntPrioritySet( INT_TIMER0A, timerHIGHEST_PRIORITY );
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122 /* Just used to measure time. */
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123 TimerLoadSet(TIMER1_BASE, TIMER_A, timerMAX_32BIT_VALUE );
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125 /* Ensure interrupts do not start until the scheduler is running. */
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126 portDISABLE_INTERRUPTS();
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128 /* The rate at which the timer will interrupt. */
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129 ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
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130 TimerLoadSet( TIMER0_BASE, TIMER_A, ulFrequency );
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131 IntEnable( INT_TIMER0A );
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132 TimerIntEnable( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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134 /* Enable both timers. */
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135 TimerEnable( TIMER0_BASE, TIMER_A );
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136 TimerEnable( TIMER1_BASE, TIMER_A );
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138 /*-----------------------------------------------------------*/
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140 void Timer0IntHandler( void )
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142 unsigned long ulDifference;
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143 volatile unsigned long ulCurrentCount;
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144 static unsigned long ulMaxDifference = 0, ulLastCount = 0;
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146 /* We use the timer 1 counter value to measure the clock cycles between
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147 the timer 0 interrupts. */
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148 ulCurrentCount = timerTIMER_1_COUNT_VALUE;
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150 TimerIntClear( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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152 if( ulCurrentCount < ulLastCount )
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154 /* How many times has timer 1 counted since the last interrupt? */
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155 ulDifference = ulLastCount - ulCurrentCount;
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157 /* Is this the largest difference we have measured yet? */
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158 if( ulDifference > ulMaxDifference )
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160 ulMaxDifference = ulDifference;
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161 ulMaxJitter = ulMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
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165 ulLastCount = ulCurrentCount;
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167 /* Keep a count of the total number of 20KHz ticks. This is used by the
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168 run time stats functionality to calculate how much CPU time is used by
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170 ulHighFrequencyTimerTicks++;
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