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134 lines
4.6 KiB
C
134 lines
4.6 KiB
C
/*
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FreeRTOS.org V4.3.0 - Copyright (C) 2003-2007 Richard Barry.
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This file is part of the FreeRTOS.org distribution.
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FreeRTOS.org is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FreeRTOS.org is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FreeRTOS.org; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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A special exception to the GPL can be applied should you wish to distribute
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a combined work that includes FreeRTOS.org, without being obliged to provide
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the source code for any proprietary components. See the licensing section
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of http://www.FreeRTOS.org for full details of how and when the exception
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can be applied.
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***************************************************************************
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See http://www.FreeRTOS.org for documentation, latest information, license
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and contact details. Please ensure to read the configuration and relevant
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port sections of the online documentation.
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Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along
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with commercial development and support options.
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***************************************************************************
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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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unsigned portLONG ulMaxJitter = 0;
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/*-----------------------------------------------------------*/
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void vSetupTimer( 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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/* 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, ulCurrentCount;
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static 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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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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TimerIntClear( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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}
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