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159 lines
5.6 KiB
C
159 lines
5.6 KiB
C
/*
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FreeRTOS V5.4.2 - Copyright (C) 2009 Real Time Engineers Ltd.
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation and modified by the FreeRTOS exception.
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**NOTE** The exception to the GPL is included to allow you to distribute a
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combined work that includes FreeRTOS without being obliged to provide the
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source code for proprietary components outside of the FreeRTOS kernel.
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Alternative commercial license and support terms are also available upon
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request. See the licensing section of http://www.FreeRTOS.org for full
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license details.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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You should have received a copy of the GNU General Public License along
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with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
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Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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***************************************************************************
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* *
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* Looking for a quick start? Then check out the FreeRTOS eBook! *
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* See http://www.FreeRTOS.org/Documentation for details *
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* *
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***************************************************************************
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1 tab == 4 spaces!
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Please ensure to read the configuration and relevant port sections of the
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online documentation.
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http://www.FreeRTOS.org - Documentation, latest information, license and
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contact details.
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http://www.SafeRTOS.com - A version that is certified for use in safety
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critical systems.
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http://www.OpenRTOS.com - Commercial support, development, porting,
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licensing and training services.
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*/
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/* High speed timer test as described in main.c. */
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/* Scheduler includes. */
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#include "FreeRTOS.h"
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/* Library includes. */
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#include "hw_ints.h"
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#include "hw_memmap.h"
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#include "hw_types.h"
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#include "interrupt.h"
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#include "sysctl.h"
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#include "lmi_timer.h"
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/* The set frequency of the interrupt. Deviations from this are measured as
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the jitter. */
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#define timerINTERRUPT_FREQUENCY ( 20000UL )
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/* The expected time between each of the timer interrupts - if the jitter was
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zero. */
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#define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
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/* The highest available interrupt priority. */
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#define timerHIGHEST_PRIORITY ( 0 )
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/* Misc defines. */
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#define timerMAX_32BIT_VALUE ( 0xffffffffUL )
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#define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) )
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/*-----------------------------------------------------------*/
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/* Interrupt handler in which the jitter is measured. */
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void Timer0IntHandler( void );
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/* Stores the value of the maximum recorded jitter between interrupts. */
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volatile unsigned portLONG ulMaxJitter = 0UL;
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/* Counts the total number of times that the high frequency timer has 'ticked'.
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This value is used by the run time stats function to work out what percentage
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of CPU time each task is taking. */
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volatile unsigned portLONG ulHighFrequencyTimerTicks = 0UL;
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/*-----------------------------------------------------------*/
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void vSetupHighFrequencyTimer( void )
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{
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unsigned long ulFrequency;
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/* Timer zero is used to generate the interrupts, and timer 1 is used
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to measure the jitter. */
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SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER0 );
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SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER1 );
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TimerConfigure( TIMER0_BASE, TIMER_CFG_32_BIT_PER );
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TimerConfigure( TIMER1_BASE, TIMER_CFG_32_BIT_PER );
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/* Set the timer interrupt to be above the kernel - highest. */
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IntPrioritySet( INT_TIMER0A, timerHIGHEST_PRIORITY );
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/* Just used to measure time. */
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TimerLoadSet(TIMER1_BASE, TIMER_A, timerMAX_32BIT_VALUE );
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/* Ensure interrupts do not start until the scheduler is running. */
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portDISABLE_INTERRUPTS();
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/* The rate at which the timer will interrupt. */
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ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
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TimerLoadSet( TIMER0_BASE, TIMER_A, ulFrequency );
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IntEnable( INT_TIMER0A );
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TimerIntEnable( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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/* Enable both timers. */
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TimerEnable( TIMER0_BASE, TIMER_A );
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TimerEnable( TIMER1_BASE, TIMER_A );
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}
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/*-----------------------------------------------------------*/
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void Timer0IntHandler( void )
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{
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unsigned portLONG ulDifference;
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volatile unsigned portLONG ulCurrentCount;
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static unsigned portLONG ulMaxDifference = 0, ulLastCount = 0;
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/* We use the timer 1 counter value to measure the clock cycles between
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the timer 0 interrupts. */
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ulCurrentCount = timerTIMER_1_COUNT_VALUE;
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TimerIntClear( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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if( ulCurrentCount < ulLastCount )
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{
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/* How many times has timer 1 counted since the last interrupt? */
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ulDifference = ulLastCount - ulCurrentCount;
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/* Is this the largest difference we have measured yet? */
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if( ulDifference > ulMaxDifference )
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{
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ulMaxDifference = ulDifference;
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ulMaxJitter = ulMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
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}
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}
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ulLastCount = ulCurrentCount;
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/* Keep a count of the total number of 20KHz ticks. This is used by the
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run time stats functionality to calculate how much CPU time is used by
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each task. */
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ulHighFrequencyTimerTicks++;
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}
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