/* | |
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. | |
*************************************************************************** | |
* * | |
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* robust, strictly quality controlled, supported, and cross * | |
* platform software that has become a de facto standard. * | |
* * | |
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*************************************************************************** | |
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. | |
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*/ | |
/* High speed timer test as described in main.c. */ | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
/* Library includes. */ | |
#include "stm32f10x_lib.h" | |
#include "stm32f10x_tim.h" | |
#include "stm32f10x_map.h" | |
/* The set frequency of the interrupt. Deviations from this are measured as | |
the jitter. */ | |
#define timerINTERRUPT_FREQUENCY ( ( unsigned short ) 20000 ) | |
/* 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 ) ) ) | |
/* The number of interrupts to pass before we start looking at the jitter. */ | |
#define timerSETTLE_TIME 5 | |
/*-----------------------------------------------------------*/ | |
/* | |
* Configures the two timers used to perform the test. | |
*/ | |
void vSetupHighFrequencyTimer( void ); | |
/* Stores the value of the maximum recorded jitter between interrupts. */ | |
volatile unsigned short usMaxJitter = 0; | |
/* Variable that counts at 20KHz to provide the time base for the run time | |
stats. */ | |
unsigned long ulRunTimeStatsClock = 0UL; | |
/*-----------------------------------------------------------*/ | |
void vSetupHighFrequencyTimer( void ) | |
{ | |
unsigned long ulFrequency; | |
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; | |
NVIC_InitTypeDef NVIC_InitStructure; | |
/* Enable timer clocks */ | |
RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM2, ENABLE ); | |
RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM3, ENABLE ); | |
/* Initialise data. */ | |
TIM_DeInit( TIM2 ); | |
TIM_DeInit( TIM3 ); | |
TIM_TimeBaseStructInit( &TIM_TimeBaseStructure ); | |
/* Time base configuration for timer 2 - which generates the interrupts. */ | |
ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY; | |
TIM_TimeBaseStructure.TIM_Period = ( unsigned short ) ( ulFrequency & 0xffffUL ); | |
TIM_TimeBaseStructure.TIM_Prescaler = 0x0; | |
TIM_TimeBaseStructure.TIM_ClockDivision = 0x0; | |
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; | |
TIM_TimeBaseInit( TIM2, &TIM_TimeBaseStructure ); | |
TIM_ARRPreloadConfig( TIM2, ENABLE ); | |
/* Configuration for timer 3 which is used as a high resolution time | |
measurement. */ | |
TIM_TimeBaseStructure.TIM_Period = ( unsigned short ) 0xffff; | |
TIM_TimeBaseInit( TIM3, &TIM_TimeBaseStructure ); | |
TIM_ARRPreloadConfig( TIM3, ENABLE ); | |
/* Enable TIM2 IT. TIM3 does not generate an interrupt. */ | |
NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQChannel; | |
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; | |
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = timerHIGHEST_PRIORITY; | |
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; | |
NVIC_Init( &NVIC_InitStructure ); | |
TIM_ITConfig( TIM2, TIM_IT_Update, ENABLE ); | |
/* Finally, enable both timers. */ | |
TIM_Cmd( TIM2, ENABLE ); | |
TIM_Cmd( TIM3, ENABLE ); | |
} | |
/*-----------------------------------------------------------*/ | |
void TIM2_IRQHandler( void ) | |
{ | |
static unsigned short usLastCount = 0, usSettleCount = 0, usMaxDifference = 0; | |
unsigned short usThisCount, usDifference; | |
/* Capture the free running timer 3 value as we enter the interrupt. */ | |
usThisCount = TIM3->CNT; | |
if( usSettleCount >= timerSETTLE_TIME ) | |
{ | |
/* What is the difference between the timer value in this interrupt | |
and the value from the last interrupt. */ | |
usDifference = usThisCount - usLastCount; | |
/* Store the difference in the timer values if it is larger than the | |
currently stored largest value. The difference over and above the | |
expected difference will give the 'jitter' in the processing of these | |
interrupts. */ | |
if( usDifference > usMaxDifference ) | |
{ | |
usMaxDifference = usDifference; | |
usMaxJitter = usMaxDifference - timerEXPECTED_DIFFERENCE_VALUE; | |
} | |
} | |
else | |
{ | |
/* Don't bother storing any values for the first couple of | |
interrupts. */ | |
usSettleCount++; | |
} | |
/* Remember what the timer value was this time through, so we can calculate | |
the difference the next time through. */ | |
usLastCount = usThisCount; | |
/* Keep a count of the number of interrupts as a time base for the run time | |
stats collection. */ | |
ulRunTimeStatsClock++; | |
TIM_ClearITPendingBit( TIM2, TIM_IT_Update ); | |
} | |