/* FreeRTOS V7.6.0 - Copyright (C) 2013 Real Time Engineers Ltd. All rights reserved VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. *************************************************************************** * * * FreeRTOS provides completely free yet professionally developed, * * robust, strictly quality controlled, supported, and cross * * platform software that has become a de facto standard. * * * * Help yourself get started quickly and support the FreeRTOS * * project by purchasing a FreeRTOS tutorial book, reference * * manual, or both from: http://www.FreeRTOS.org/Documentation * * * * Thank you! * * * *************************************************************************** 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 1 tab == 4 spaces! *************************************************************************** * * * Having a problem? Start by reading the FAQ "My application does * * not run, what could be wrong?" * * * * http://www.FreeRTOS.org/FAQHelp.html * * * *************************************************************************** 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.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS licenses offer ticketed support, indemnification and 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 portLONG ) 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 portLONG 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 portLONG ulDifference; volatile unsigned portLONG ulCurrentCount; static unsigned portLONG 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; }