2 FreeRTOS V7.5.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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6 ***************************************************************************
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8 * FreeRTOS provides completely free yet professionally developed, *
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9 * robust, strictly quality controlled, supported, and cross *
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10 * platform software that has become a de facto standard. *
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12 * Help yourself get started quickly and support the FreeRTOS *
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13 * project by purchasing a FreeRTOS tutorial book, reference *
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14 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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18 ***************************************************************************
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20 This file is part of the FreeRTOS distribution.
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22 FreeRTOS is free software; you can redistribute it and/or modify it under
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23 the terms of the GNU General Public License (version 2) as published by the
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24 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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26 >>! NOTE: The modification to the GPL is included to allow you to distribute
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27 >>! a combined work that includes FreeRTOS without being obliged to provide
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28 >>! the source code for proprietary components outside of the FreeRTOS
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31 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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32 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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33 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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34 link: http://www.freertos.org/a00114.html
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38 ***************************************************************************
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40 * Having a problem? Start by reading the FAQ "My application does *
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41 * not run, what could be wrong?" *
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43 * http://www.FreeRTOS.org/FAQHelp.html *
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45 ***************************************************************************
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47 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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48 license and Real Time Engineers Ltd. contact details.
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50 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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51 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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52 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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54 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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55 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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56 licenses offer ticketed support, indemnification and middleware.
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58 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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59 engineered and independently SIL3 certified version for use in safety and
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60 mission critical applications that require provable dependability.
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65 /* High speed timer test as described in main.c. */
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67 /* Scheduler includes. */
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68 #include "FreeRTOS.h"
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70 /* Library includes. */
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71 #include "hw_ints.h"
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72 #include "hw_memmap.h"
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73 #include "hw_types.h"
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74 #include "interrupt.h"
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76 #include "lmi_timer.h"
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78 /* The set frequency of the interrupt. Deviations from this are measured as
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80 #define timerINTERRUPT_FREQUENCY ( 20000UL )
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82 /* The expected time between each of the timer interrupts - if the jitter was
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84 #define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
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86 /* The highest available interrupt priority. */
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87 #define timerHIGHEST_PRIORITY ( 0 )
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90 #define timerMAX_32BIT_VALUE ( 0xffffffffUL )
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91 #define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) )
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93 /*-----------------------------------------------------------*/
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95 /* Interrupt handler in which the jitter is measured. */
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96 void Timer0IntHandler( void );
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98 /* Stores the value of the maximum recorded jitter between interrupts. */
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99 volatile unsigned portLONG ulMaxJitter = 0UL;
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101 /* Counts the total number of times that the high frequency timer has 'ticked'.
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102 This value is used by the run time stats function to work out what percentage
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103 of CPU time each task is taking. */
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104 volatile unsigned portLONG ulHighFrequencyTimerTicks = 0UL;
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105 /*-----------------------------------------------------------*/
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107 void vSetupHighFrequencyTimer( void )
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109 unsigned long ulFrequency;
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111 /* Timer zero is used to generate the interrupts, and timer 1 is used
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112 to measure the jitter. */
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113 SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER0 );
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114 SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER1 );
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115 TimerConfigure( TIMER0_BASE, TIMER_CFG_32_BIT_PER );
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116 TimerConfigure( TIMER1_BASE, TIMER_CFG_32_BIT_PER );
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118 /* Set the timer interrupt to be above the kernel - highest. */
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119 IntPrioritySet( INT_TIMER0A, timerHIGHEST_PRIORITY );
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121 /* Just used to measure time. */
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122 TimerLoadSet(TIMER1_BASE, TIMER_A, timerMAX_32BIT_VALUE );
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124 /* Ensure interrupts do not start until the scheduler is running. */
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125 portDISABLE_INTERRUPTS();
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127 /* The rate at which the timer will interrupt. */
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128 ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
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129 TimerLoadSet( TIMER0_BASE, TIMER_A, ulFrequency );
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130 IntEnable( INT_TIMER0A );
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131 TimerIntEnable( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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133 /* Enable both timers. */
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134 TimerEnable( TIMER0_BASE, TIMER_A );
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135 TimerEnable( TIMER1_BASE, TIMER_A );
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137 /*-----------------------------------------------------------*/
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139 void Timer0IntHandler( void )
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141 unsigned portLONG ulDifference;
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142 volatile unsigned portLONG ulCurrentCount;
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143 static unsigned portLONG ulMaxDifference = 0, ulLastCount = 0;
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145 /* We use the timer 1 counter value to measure the clock cycles between
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146 the timer 0 interrupts. */
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147 ulCurrentCount = timerTIMER_1_COUNT_VALUE;
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149 TimerIntClear( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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151 if( ulCurrentCount < ulLastCount )
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153 /* How many times has timer 1 counted since the last interrupt? */
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154 ulDifference = ulLastCount - ulCurrentCount;
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156 /* Is this the largest difference we have measured yet? */
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157 if( ulDifference > ulMaxDifference )
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159 ulMaxDifference = ulDifference;
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160 ulMaxJitter = ulMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
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164 ulLastCount = ulCurrentCount;
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166 /* Keep a count of the total number of 20KHz ticks. This is used by the
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167 run time stats functionality to calculate how much CPU time is used by
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169 ulHighFrequencyTimerTicks++;
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