/* FreeRTOS V8.2.0rc1 - Copyright (C) 2014 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 1 tab == 4 spaces! *************************************************************************** * * * Having a problem? Start by reading the FAQ "My application does * * not run, what could be wrong?". Have you defined configASSERT()? * * * * http://www.FreeRTOS.org/FAQHelp.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 * * * *************************************************************************** *************************************************************************** * * * Investing in training allows your team to be as productive as * * possible as early as possible, lowering your overall development * * cost, and enabling you to bring a more robust product to market * * earlier than would otherwise be possible. Richard Barry is both * * the architect and key author of FreeRTOS, and so also the world's * * leading authority on what is the world's most popular real time * * kernel for deeply embedded MCU designs. Obtaining your training * * from Richard ensures your team will gain directly from his in-depth * * product knowledge and years of usage experience. Contact Real Time * * Engineers Ltd to enquire about the FreeRTOS Masterclass, presented * * by Richard Barry: http://www.FreeRTOS.org/contact * * *************************************************************************** *************************************************************************** * * * You are receiving this top quality software for free. Please play * * fair and reciprocate by reporting any suspected issues and * * participating in the community forum: * * http://www.FreeRTOS.org/support * * * * Thank you! * * * *************************************************************************** http://www.FreeRTOS.org - Documentation, books, training, latest versions, license and Real Time Engineers Ltd. contact details. 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 speed timer test as described in main.c. */ /* Scheduler includes. */ #include "FreeRTOS.h" /* Library includes. */ #include "hw_ints.h" #include "hw_memmap.h" #include "hw_types.h" #include "interrupt.h" #include "sysctl.h" #include "lmi_timer.h" #include "hw_timer.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 ( 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 ( * ( ( volatile unsigned long * ) ( ( unsigned long ) TIMER1_BASE + 0x48UL ) ) ) /*-----------------------------------------------------------*/ /* Interrupt handler in which the jitter is measured. */ void Timer0IntHandler( void ); /* Stores the value of the maximum recorded jitter between interrupts. */ volatile unsigned long ulMaxJitter = 0; /*-----------------------------------------------------------*/ void vSetupHighFrequencyTimer( void ) { unsigned long ulFrequency; /* Timer zero is used to generate the interrupts, and timer 1 is used to measure the jitter. */ SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER0 ); SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER1 ); TimerConfigure( TIMER0_BASE, TIMER_CFG_32_BIT_PER ); TimerConfigure( TIMER1_BASE, TIMER_CFG_32_BIT_PER ); /* Set the timer interrupt to be above the kernel - highest. */ IntPrioritySet( INT_TIMER0A, timerHIGHEST_PRIORITY ); /* Just used to measure time. */ TimerLoadSet(TIMER1_BASE, TIMER_A, timerMAX_32BIT_VALUE ); /* Ensure interrupts do not start until the scheduler is running. */ portDISABLE_INTERRUPTS(); /* The rate at which the timer will interrupt. */ ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY; TimerLoadSet( TIMER0_BASE, TIMER_A, ulFrequency ); IntEnable( INT_TIMER0A ); TimerIntEnable( TIMER0_BASE, TIMER_TIMA_TIMEOUT ); /* Enable both timers. */ TimerEnable( TIMER0_BASE, TIMER_A ); TimerEnable( TIMER1_BASE, TIMER_A ); } /*-----------------------------------------------------------*/ void Timer0IntHandler( void ) { unsigned long ulDifference; volatile unsigned long ulCurrentCount; static unsigned long ulMaxDifference = 0, ulLastCount = 0; /* We use the timer 1 counter value to measure the clock cycles between the timer 0 interrupts. */ ulCurrentCount = timerTIMER_1_COUNT_VALUE; TimerIntClear( TIMER0_BASE, TIMER_TIMA_TIMEOUT ); if( ulCurrentCount < ulLastCount ) { /* How many times has timer 1 counted since the last interrupt? */ ulDifference = ulLastCount - ulCurrentCount; /* Is this the largest difference we have measured yet? */ if( ulDifference > ulMaxDifference ) { ulMaxDifference = ulDifference; ulMaxJitter = ulMaxDifference - timerEXPECTED_DIFFERENCE_VALUE; } } ulLastCount = ulCurrentCount; }