2 FreeRTOS V7.2.0 - Copyright (C) 2012 Real Time Engineers Ltd.
\r
5 ***************************************************************************
\r
7 * FreeRTOS tutorial books are available in pdf and paperback. *
\r
8 * Complete, revised, and edited pdf reference manuals are also *
\r
11 * Purchasing FreeRTOS documentation will not only help you, by *
\r
12 * ensuring you get running as quickly as possible and with an *
\r
13 * in-depth knowledge of how to use FreeRTOS, it will also help *
\r
14 * the FreeRTOS project to continue with its mission of providing *
\r
15 * professional grade, cross platform, de facto standard solutions *
\r
16 * for microcontrollers - completely free of charge! *
\r
18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
\r
20 * Thank you for using FreeRTOS, and thank you for your support! *
\r
22 ***************************************************************************
\r
25 This file is part of the FreeRTOS distribution.
\r
27 FreeRTOS is free software; you can redistribute it and/or modify it under
\r
28 the terms of the GNU General Public License (version 2) as published by the
\r
29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
\r
30 >>>NOTE<<< The modification to the GPL is included to allow you to
\r
31 distribute a combined work that includes FreeRTOS without being obliged to
\r
32 provide the source code for proprietary components outside of the FreeRTOS
\r
33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
\r
34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
\r
35 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
\r
36 more details. You should have received a copy of the GNU General Public
\r
37 License and the FreeRTOS license exception along with FreeRTOS; if not it
\r
38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
\r
39 by writing to Richard Barry, contact details for whom are available on the
\r
44 ***************************************************************************
\r
46 * Having a problem? Start by reading the FAQ "My application does *
\r
47 * not run, what could be wrong? *
\r
49 * http://www.FreeRTOS.org/FAQHelp.html *
\r
51 ***************************************************************************
\r
54 http://www.FreeRTOS.org - Documentation, training, latest information,
\r
55 license and contact details.
\r
57 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
\r
58 including FreeRTOS+Trace - an indispensable productivity tool.
\r
60 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
\r
61 the code with commercial support, indemnification, and middleware, under
\r
62 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
\r
63 provide a safety engineered and independently SIL3 certified version under
\r
64 the SafeRTOS brand: http://www.SafeRTOS.com.
\r
67 /* High speed timer test as described in main.c. */
\r
69 /* Scheduler includes. */
\r
70 #include "FreeRTOS.h"
\r
72 /* Library includes. */
\r
73 #include "hw_ints.h"
\r
74 #include "hw_memmap.h"
\r
75 #include "hw_types.h"
\r
76 #include "interrupt.h"
\r
78 #include "lmi_timer.h"
\r
80 /* The set frequency of the interrupt. Deviations from this are measured as
\r
82 #define timerINTERRUPT_FREQUENCY ( 20000UL )
\r
84 /* The expected time between each of the timer interrupts - if the jitter was
\r
86 #define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
\r
88 /* The highest available interrupt priority. */
\r
89 #define timerHIGHEST_PRIORITY ( 0 )
\r
92 #define timerMAX_32BIT_VALUE ( 0xffffffffUL )
\r
93 #define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) )
\r
95 /*-----------------------------------------------------------*/
\r
97 /* Interrupt handler in which the jitter is measured. */
\r
98 void Timer0IntHandler( void );
\r
100 /* Stores the value of the maximum recorded jitter between interrupts. */
\r
101 volatile unsigned portLONG ulMaxJitter = 0UL;
\r
103 /* Counts the total number of times that the high frequency timer has 'ticked'.
\r
104 This value is used by the run time stats function to work out what percentage
\r
105 of CPU time each task is taking. */
\r
106 volatile unsigned portLONG ulHighFrequencyTimerTicks = 0UL;
\r
107 /*-----------------------------------------------------------*/
\r
109 void vSetupHighFrequencyTimer( void )
\r
111 unsigned long ulFrequency;
\r
113 /* Timer zero is used to generate the interrupts, and timer 1 is used
\r
114 to measure the jitter. */
\r
115 SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER0 );
\r
116 SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER1 );
\r
117 TimerConfigure( TIMER0_BASE, TIMER_CFG_32_BIT_PER );
\r
118 TimerConfigure( TIMER1_BASE, TIMER_CFG_32_BIT_PER );
\r
120 /* Set the timer interrupt to be above the kernel - highest. */
\r
121 IntPrioritySet( INT_TIMER0A, timerHIGHEST_PRIORITY );
\r
123 /* Just used to measure time. */
\r
124 TimerLoadSet(TIMER1_BASE, TIMER_A, timerMAX_32BIT_VALUE );
\r
126 /* Ensure interrupts do not start until the scheduler is running. */
\r
127 portDISABLE_INTERRUPTS();
\r
129 /* The rate at which the timer will interrupt. */
\r
130 ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
\r
131 TimerLoadSet( TIMER0_BASE, TIMER_A, ulFrequency );
\r
132 IntEnable( INT_TIMER0A );
\r
133 TimerIntEnable( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
\r
135 /* Enable both timers. */
\r
136 TimerEnable( TIMER0_BASE, TIMER_A );
\r
137 TimerEnable( TIMER1_BASE, TIMER_A );
\r
139 /*-----------------------------------------------------------*/
\r
141 void Timer0IntHandler( void )
\r
143 unsigned portLONG ulDifference;
\r
144 volatile unsigned portLONG ulCurrentCount;
\r
145 static unsigned portLONG ulMaxDifference = 0, ulLastCount = 0;
\r
147 /* We use the timer 1 counter value to measure the clock cycles between
\r
148 the timer 0 interrupts. */
\r
149 ulCurrentCount = timerTIMER_1_COUNT_VALUE;
\r
151 TimerIntClear( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
\r
153 if( ulCurrentCount < ulLastCount )
\r
155 /* How many times has timer 1 counted since the last interrupt? */
\r
156 ulDifference = ulLastCount - ulCurrentCount;
\r
158 /* Is this the largest difference we have measured yet? */
\r
159 if( ulDifference > ulMaxDifference )
\r
161 ulMaxDifference = ulDifference;
\r
162 ulMaxJitter = ulMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
\r
166 ulLastCount = ulCurrentCount;
\r
168 /* Keep a count of the total number of 20KHz ticks. This is used by the
\r
169 run time stats functionality to calculate how much CPU time is used by
\r
171 ulHighFrequencyTimerTicks++;
\r