/* | |
FreeRTOS V7.0.1 - 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 speed timer test as described in main.c. */ | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
/* The maximum value the 16bit timer can contain. */ | |
#define timerMAX_COUNT 0xffff | |
/* The timer 2 interrupt handler. As this interrupt uses the FreeRTOS assembly | |
entry point the IPL setting in the following function prototype has no effect. | |
The interrupt priority is set by ConfigIntTimer2() in vSetupTimerTest(). */ | |
void __attribute__( (interrupt(ipl0), vector(_TIMER_2_VECTOR))) vT2InterruptWrapper( void ); | |
/*-----------------------------------------------------------*/ | |
/* Incremented every 20,000 interrupts, so should count in seconds. */ | |
unsigned long ulHighFrequencyTimerInterrupts = 0; | |
/* The frequency at which the timer is interrupting. */ | |
static unsigned long ulFrequencyHz; | |
/*-----------------------------------------------------------*/ | |
void vSetupTimerTest( unsigned short usFrequencyHz ) | |
{ | |
/* Remember the frequency so it can be used from the ISR. */ | |
ulFrequencyHz = ( unsigned long ) usFrequencyHz; | |
/* T2 is used to generate interrupts above the kernel and max syscall interrupt | |
priority. */ | |
T2CON = 0; | |
TMR2 = 0; | |
/* Timer 2 is going to interrupt at usFrequencyHz Hz. */ | |
PR2 = ( unsigned short ) ( ( configPERIPHERAL_CLOCK_HZ / ( unsigned long ) usFrequencyHz ) - 1 ); | |
/* Setup timer 2 interrupt priority to be above the kernel priority so | |
the timer jitter is not effected by the kernel activity. */ | |
ConfigIntTimer2( T2_INT_ON | ( configMAX_SYSCALL_INTERRUPT_PRIORITY + 1 ) ); | |
/* Clear the interrupt as a starting condition. */ | |
IFS0bits.T2IF = 0; | |
/* Enable the interrupt. */ | |
IEC0bits.T2IE = 1; | |
/* Start the timer. */ | |
T2CONbits.TON = 1; | |
} | |
/*-----------------------------------------------------------*/ | |
void vT2InterruptHandler( void ) | |
{ | |
static unsigned long ulCalls = 0; | |
++ulCalls; | |
if( ulCalls >= ulFrequencyHz ) | |
{ | |
/* Increment the count that will be shown on the LCD. | |
The increment occurs once every 20,000 interrupts so | |
ulHighFrequencyTimerInterrupts should count in seconds. */ | |
ulHighFrequencyTimerInterrupts++; | |
ulCalls = 0; | |
} | |
/* Clear the timer interrupt. */ | |
IFS0bits.T2IF = 0; | |
} | |