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/*
FreeRTOS V8.2.0 - Copyright (C) 2015 Real Time Engineers Ltd.
All rights reserved
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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 on the following
link: http://www.freertos.org/a00114.html
***************************************************************************
* *
* FreeRTOS provides completely free yet professionally developed, *
* robust, strictly quality controlled, supported, and cross *
* platform software that is more than just the market leader, it *
* is the industry's de facto standard. *
* *
* Help yourself get started quickly while simultaneously helping *
* to support the FreeRTOS project by purchasing a FreeRTOS *
* tutorial book, reference manual, or both: *
* http://www.FreeRTOS.org/Documentation *
* *
***************************************************************************
http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
the FAQ page "My application does not run, what could be wrong?". Have you
defined configASSERT()?
http://www.FreeRTOS.org/support - In return for receiving this top quality
embedded software for free we request you assist our global community by
participating in the support forum.
http://www.FreeRTOS.org/training - Investing in training allows your team to
be as productive as possible as early as possible. Now you can receive
FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
Ltd, and the world's leading authority on the world's leading RTOS.
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool, a DOS
compatible FAT file system, and our tiny thread aware UDP/IP stack.
http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
licenses offer ticketed support, indemnification and commercial middleware.
http://www.SafeRTOS.com - High Integrity Systems also provide a safety
engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
1 tab == 4 spaces!
*/
/*
* High frequency timer test as described in main.c.
*/
/* Scheduler includes. */
#include "FreeRTOS.h"
/* Hardware specifics. */
#include "iodefine.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 ( ( unsigned short ) ( ( configPERIPHERAL_CLOCK_HZ / 8UL ) / timerINTERRUPT_FREQUENCY ) )
/* The highest available interrupt priority. */
#define timerHIGHEST_PRIORITY ( 15 )
/* Misc defines. */
#define timerTIMER_3_COUNT_VALUE ( *( ( unsigned short * ) 0x8801a ) ) /*( CMT3.CMCNT )*/
/*-----------------------------------------------------------*/
/* Interrupt handler in which the jitter is measured. */
static void prvTimer2IntHandler( void );
/* Stores the value of the maximum recorded jitter between interrupts. This is
displayed on one of the served web pages. */
volatile unsigned short usMaxJitter = 0;
/* Counts the number of high frequency interrupts - used to generate the run
time stats. */
volatile unsigned long ulHighFrequencyTickCount = 0UL;
/*-----------------------------------------------------------*/
void vSetupHighFrequencyTimer( void )
{
/* Timer CMT2 is used to generate the interrupts, and CMT3 is used
to measure the jitter. */
/* Enable compare match timer 2 and 3. */
MSTP( CMT2 ) = 0;
MSTP( CMT3 ) = 0;
/* Interrupt on compare match. */
CMT2.CMCR.BIT.CMIE = 1;
/* Set the compare match value. */
CMT2.CMCOR = ( unsigned short ) ( ( ( configPERIPHERAL_CLOCK_HZ / timerINTERRUPT_FREQUENCY ) -1 ) / 8 );
/* Divide the PCLK by 8. */
CMT2.CMCR.BIT.CKS = 0;
CMT3.CMCR.BIT.CKS = 0;
/* Enable the interrupt... */
_IEN( _CMT2_CMI2 ) = 1;
/* ...and set its priority to the maximum possible, this is above the priority
set by configMAX_SYSCALL_INTERRUPT_PRIORITY so will nest. */
_IPR( _CMT2_CMI2 ) = timerHIGHEST_PRIORITY;
/* Start the timers. */
CMT.CMSTR1.BIT.STR2 = 1;
CMT.CMSTR1.BIT.STR3 = 1;
}
/*-----------------------------------------------------------*/
#pragma interrupt ( prvTimer2IntHandler( vect = _VECT( _CMT2_CMI2 ), enable ) )
static void prvTimer2IntHandler( void )
{
volatile unsigned short usCurrentCount;
static unsigned short usMaxCount = 0;
static unsigned long ulErrorCount = 0UL;
/* We use the timer 1 counter value to measure the clock cycles between
the timer 0 interrupts. First stop the clock. */
CMT.CMSTR1.BIT.STR3 = 0;
nop();
nop();
usCurrentCount = timerTIMER_3_COUNT_VALUE;
/* Is this the largest count we have measured yet? */
if( usCurrentCount > usMaxCount )
{
if( usCurrentCount > timerEXPECTED_DIFFERENCE_VALUE )
{
usMaxJitter = usCurrentCount - timerEXPECTED_DIFFERENCE_VALUE;
}
else
{
/* This should not happen! */
ulErrorCount++;
}
usMaxCount = usCurrentCount;
}
/* Used to generate the run time stats. */
ulHighFrequencyTickCount++;
/* Clear the timer. */
timerTIMER_3_COUNT_VALUE = 0;
/* Then start the clock again. */
CMT.CMSTR1.BIT.STR3 = 1;
}
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