2 FreeRTOS V7.4.0 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not itcan be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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75 /* High speed timer test as described in main.c. */
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77 /* Scheduler includes. */
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78 #include "FreeRTOS.h"
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80 /* Library includes. */
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81 #include "hw_ints.h"
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82 #include "hw_memmap.h"
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83 #include "hw_types.h"
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84 #include "interrupt.h"
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86 #include "lmi_timer.h"
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88 /* The set frequency of the interrupt. Deviations from this are measured as
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90 #define timerINTERRUPT_FREQUENCY ( 20000UL )
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92 /* The expected time between each of the timer interrupts - if the jitter was
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94 #define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
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96 /* The highest available interrupt priority. */
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97 #define timerHIGHEST_PRIORITY ( 0 )
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100 #define timerMAX_32BIT_VALUE ( 0xffffffffUL )
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101 #define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) )
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103 /*-----------------------------------------------------------*/
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105 /* Interrupt handler in which the jitter is measured. */
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106 void Timer0IntHandler( void );
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108 /* Stores the value of the maximum recorded jitter between interrupts. */
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109 volatile unsigned portLONG ulMaxJitter = 0UL;
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111 /* Counts the total number of times that the high frequency timer has 'ticked'.
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112 This value is used by the run time stats function to work out what percentage
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113 of CPU time each task is taking. */
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114 volatile unsigned portLONG ulHighFrequencyTimerTicks = 0UL;
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115 /*-----------------------------------------------------------*/
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117 void vSetupHighFrequencyTimer( void )
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119 unsigned long ulFrequency;
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121 /* Timer zero is used to generate the interrupts, and timer 1 is used
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122 to measure the jitter. */
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123 SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER0 );
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124 SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER1 );
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125 TimerConfigure( TIMER0_BASE, TIMER_CFG_32_BIT_PER );
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126 TimerConfigure( TIMER1_BASE, TIMER_CFG_32_BIT_PER );
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128 /* Set the timer interrupt to be above the kernel - highest. */
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129 IntPrioritySet( INT_TIMER0A, timerHIGHEST_PRIORITY );
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131 /* Just used to measure time. */
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132 TimerLoadSet(TIMER1_BASE, TIMER_A, timerMAX_32BIT_VALUE );
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134 /* Ensure interrupts do not start until the scheduler is running. */
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135 portDISABLE_INTERRUPTS();
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137 /* The rate at which the timer will interrupt. */
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138 ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
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139 TimerLoadSet( TIMER0_BASE, TIMER_A, ulFrequency );
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140 IntEnable( INT_TIMER0A );
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141 TimerIntEnable( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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143 /* Enable both timers. */
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144 TimerEnable( TIMER0_BASE, TIMER_A );
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145 TimerEnable( TIMER1_BASE, TIMER_A );
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147 /*-----------------------------------------------------------*/
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149 void Timer0IntHandler( void )
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151 unsigned portLONG ulDifference;
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152 volatile unsigned portLONG ulCurrentCount;
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153 static unsigned portLONG ulMaxDifference = 0, ulLastCount = 0;
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155 /* We use the timer 1 counter value to measure the clock cycles between
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156 the timer 0 interrupts. */
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157 ulCurrentCount = timerTIMER_1_COUNT_VALUE;
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159 TimerIntClear( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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161 if( ulCurrentCount < ulLastCount )
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163 /* How many times has timer 1 counted since the last interrupt? */
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164 ulDifference = ulLastCount - ulCurrentCount;
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166 /* Is this the largest difference we have measured yet? */
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167 if( ulDifference > ulMaxDifference )
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169 ulMaxDifference = ulDifference;
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170 ulMaxJitter = ulMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
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174 ulLastCount = ulCurrentCount;
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176 /* Keep a count of the total number of 20KHz ticks. This is used by the
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177 run time stats functionality to calculate how much CPU time is used by
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179 ulHighFrequencyTimerTicks++;
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