/* | |
* FreeRTOS Kernel V10.2.1 | |
* Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved. | |
* | |
* Permission is hereby granted, free of charge, to any person obtaining a copy of | |
* this software and associated documentation files (the "Software"), to deal in | |
* the Software without restriction, including without limitation the rights to | |
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of | |
* the Software, and to permit persons to whom the Software is furnished to do so, | |
* subject to the following conditions: | |
* | |
* The above copyright notice and this permission notice shall be included in all | |
* copies or substantial portions of the Software. | |
* | |
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS | |
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR | |
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER | |
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | |
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. | |
* | |
* http://www.FreeRTOS.org | |
* http://aws.amazon.com/freertos | |
* | |
* 1 tab == 4 spaces! | |
*/ | |
/* High speed timer test as described in main.c. */ | |
#include <device.h> | |
/* Scheduler includes. */ | |
#include "FreeRTOS.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 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 vSetupTimerTest( void ); | |
/* Interrupt handler in which the jitter is measured. */ | |
CY_ISR_PROTO(vTimer20KHzISR); | |
/* Stores the value of the maximum recorded jitter between interrupts. */ | |
volatile unsigned short usMaxJitter = 0; | |
/*---------------------------------------------------------------------------*/ | |
void vSetupTimerTest( void ) | |
{ | |
/* Install the ISR. */ | |
isrTimer_20KHz_TC_StartEx(vTimer20KHzISR); | |
} | |
/*---------------------------------------------------------------------------*/ | |
CY_ISR(vTimer20KHzISR) | |
{ | |
static unsigned short usLastCount = 0, usSettleCount = 0, usMaxDifference = 0; | |
unsigned short usThisCount, usDifference; | |
/* Capture the free running timer value as we enter the interrupt. */ | |
usThisCount = Timer_48MHz_ReadCounter(); | |
if( usSettleCount >= timerSETTLE_TIME ) | |
{ | |
/* What is the difference between the timer value in this interrupt | |
and the value from the last interrupt. Timer counts down. */ | |
usDifference = usLastCount + ~usThisCount + 1; | |
/* 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; | |
/* Calculate the Jitter based on the difference we expect. */ | |
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; | |
} | |
/*---------------------------------------------------------------------------*/ |