/* | |
FreeRTOS V8.0.1 - Copyright (C) 2014 Real Time Engineers Ltd. | |
All rights reserved | |
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. | |
*************************************************************************** | |
* * | |
* FreeRTOS provides completely free yet professionally developed, * | |
* robust, strictly quality controlled, supported, and cross * | |
* platform software that has become a de facto standard. * | |
* * | |
* Help yourself get started quickly and support the FreeRTOS * | |
* project by purchasing a FreeRTOS tutorial book, reference * | |
* manual, or both from: http://www.FreeRTOS.org/Documentation * | |
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* Thank you! * | |
* * | |
*************************************************************************** | |
This file is part of the FreeRTOS distribution. | |
FreeRTOS is free software; you can redistribute it and/or modify it under | |
the terms of the GNU General Public License (version 2) as published by the | |
Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception. | |
>>! NOTE: The modification to the GPL is included to allow you to !<< | |
>>! distribute a combined work that includes FreeRTOS without being !<< | |
>>! obliged to provide the source code for proprietary components !<< | |
>>! outside of the FreeRTOS kernel. !<< | |
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY | |
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | |
FOR A PARTICULAR PURPOSE. Full license text is available from the following | |
link: http://www.freertos.org/a00114.html | |
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*************************************************************************** | |
* * | |
* Having a problem? Start by reading the FAQ "My application does * | |
* not run, what could be wrong?" * | |
* * | |
* http://www.FreeRTOS.org/FAQHelp.html * | |
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*************************************************************************** | |
http://www.FreeRTOS.org - Documentation, books, training, latest versions, | |
license and Real Time Engineers Ltd. contact details. | |
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products, | |
including FreeRTOS+Trace - an indispensable productivity tool, a DOS | |
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*/ | |
/* High speed timer test as described in main.c. */ | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
/* Library includes. */ | |
#include "hw_ints.h" | |
#include "hw_memmap.h" | |
#include "hw_types.h" | |
#include "interrupt.h" | |
#include "sysctl.h" | |
#include "lmi_timer.h" | |
/* The set frequency of the interrupt. Deviations from this are measured as | |
the jitter. */ | |
#define timerINTERRUPT_FREQUENCY ( 20000UL ) | |
/* The expected time between each of the timer interrupts - if the jitter was | |
zero. */ | |
#define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY ) | |
/* The highest available interrupt priority. */ | |
#define timerHIGHEST_PRIORITY ( 0 ) | |
/* Misc defines. */ | |
#define timerMAX_32BIT_VALUE ( 0xffffffffUL ) | |
#define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) ) | |
/*-----------------------------------------------------------*/ | |
/* Interrupt handler in which the jitter is measured. */ | |
void Timer0IntHandler( void ); | |
/* Stores the value of the maximum recorded jitter between interrupts. */ | |
volatile unsigned long ulMaxJitter = 0UL; | |
/* Counts the total number of times that the high frequency timer has 'ticked'. | |
This value is used by the run time stats function to work out what percentage | |
of CPU time each task is taking. */ | |
volatile unsigned long ulHighFrequencyTimerTicks = 0UL; | |
/*-----------------------------------------------------------*/ | |
void vSetupHighFrequencyTimer( void ) | |
{ | |
unsigned long ulFrequency; | |
/* Timer zero is used to generate the interrupts, and timer 1 is used | |
to measure the jitter. */ | |
SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER0 ); | |
SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER1 ); | |
TimerConfigure( TIMER0_BASE, TIMER_CFG_32_BIT_PER ); | |
TimerConfigure( TIMER1_BASE, TIMER_CFG_32_BIT_PER ); | |
/* Set the timer interrupt to be above the kernel - highest. */ | |
IntPrioritySet( INT_TIMER0A, timerHIGHEST_PRIORITY ); | |
/* Just used to measure time. */ | |
TimerLoadSet(TIMER1_BASE, TIMER_A, timerMAX_32BIT_VALUE ); | |
/* Ensure interrupts do not start until the scheduler is running. */ | |
portDISABLE_INTERRUPTS(); | |
/* The rate at which the timer will interrupt. */ | |
ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY; | |
TimerLoadSet( TIMER0_BASE, TIMER_A, ulFrequency ); | |
IntEnable( INT_TIMER0A ); | |
TimerIntEnable( TIMER0_BASE, TIMER_TIMA_TIMEOUT ); | |
/* Enable both timers. */ | |
TimerEnable( TIMER0_BASE, TIMER_A ); | |
TimerEnable( TIMER1_BASE, TIMER_A ); | |
} | |
/*-----------------------------------------------------------*/ | |
void Timer0IntHandler( void ) | |
{ | |
unsigned long ulDifference; | |
volatile unsigned long ulCurrentCount; | |
static unsigned long ulMaxDifference = 0, ulLastCount = 0; | |
/* We use the timer 1 counter value to measure the clock cycles between | |
the timer 0 interrupts. */ | |
ulCurrentCount = timerTIMER_1_COUNT_VALUE; | |
TimerIntClear( TIMER0_BASE, TIMER_TIMA_TIMEOUT ); | |
if( ulCurrentCount < ulLastCount ) | |
{ | |
/* How many times has timer 1 counted since the last interrupt? */ | |
ulDifference = ulLastCount - ulCurrentCount; | |
/* Is this the largest difference we have measured yet? */ | |
if( ulDifference > ulMaxDifference ) | |
{ | |
ulMaxDifference = ulDifference; | |
ulMaxJitter = ulMaxDifference - timerEXPECTED_DIFFERENCE_VALUE; | |
} | |
} | |
ulLastCount = ulCurrentCount; | |
/* Keep a count of the total number of 20KHz ticks. This is used by the | |
run time stats functionality to calculate how much CPU time is used by | |
each task. */ | |
ulHighFrequencyTimerTicks++; | |
} | |