/* | |
FreeRTOS V7.0.0 - Copyright (C) 2011 Real Time Engineers Ltd. | |
*************************************************************************** | |
* * | |
* FreeRTOS tutorial books are available in pdf and paperback. * | |
* Complete, revised, and edited pdf reference manuals are also * | |
* available. * | |
* * | |
* Purchasing FreeRTOS documentation will not only help you, by * | |
* ensuring you get running as quickly as possible and with an * | |
* in-depth knowledge of how to use FreeRTOS, it will also help * | |
* the FreeRTOS project to continue with its mission of providing * | |
* professional grade, cross platform, de facto standard solutions * | |
* for microcontrollers - completely free of charge! * | |
* * | |
* >>> See http://www.FreeRTOS.org/Documentation for details. <<< * | |
* * | |
* Thank you for using FreeRTOS, and thank you for your support! * | |
* * | |
*************************************************************************** | |
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. See the GNU General Public License for | |
more details. You should have received a copy of the GNU General Public | |
License and the FreeRTOS license exception along with FreeRTOS; if not it | |
can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
by writing to Richard Barry, contact details for whom are available on the | |
FreeRTOS WEB site. | |
1 tab == 4 spaces! | |
http://www.FreeRTOS.org - Documentation, latest information, license and | |
contact details. | |
http://www.SafeRTOS.com - A version that is certified for use in safety | |
critical systems. | |
http://www.OpenRTOS.com - Commercial support, development, porting, | |
licensing and training services. | |
*/ | |
/* | |
* 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. */ | |
void vTimer2_ISR_Handler( void ) __attribute__((interrupt)); | |
/* 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; | |
} | |
/*-----------------------------------------------------------*/ | |
void vTimer2_ISR_Handler( void ) | |
{ | |
volatile unsigned short usCurrentCount; | |
static unsigned short usMaxCount = 0; | |
static unsigned long ulErrorCount = 0UL; | |
/* This is the highest priority interrupt in the system, so there is no | |
advantage to re-enabling interrupts here. | |
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; | |
portNOP(); | |
portNOP(); | |
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; | |
} | |