/* FreeRTOS V8.1.0 - Copyright (C) 2014 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 frequency timer test as described in main.c. */ /* Scheduler includes. */ #include "FreeRTOS.h" /* Hardware specifics. */ #include "iodefine.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 ( ( unsigned short ) ( ( configPERIPHERAL_CLOCK_HZ / 8UL ) / timerINTERRUPT_FREQUENCY ) ) /* The highest available interrupt priority. */ #define timerHIGHEST_PRIORITY ( 15 ) /* Misc defines. */ #define timerTIMER_3_COUNT_VALUE ( *( ( unsigned short * ) 0x8801a ) ) /*( CMT3.CMCNT )*/ /*-----------------------------------------------------------*/ /* Interrupt handler in which the jitter is measured. */ static void prvTimer2IntHandler( void ); /* Stores the value of the maximum recorded jitter between interrupts. This is displayed on one of the served web pages. */ volatile unsigned short usMaxJitter = 0; /* Counts the number of high frequency interrupts - used to generate the run time stats. */ volatile unsigned long ulHighFrequencyTickCount = 0UL; /*-----------------------------------------------------------*/ void vSetupHighFrequencyTimer( void ) { /* Timer CMT2 is used to generate the interrupts, and CMT3 is used to measure the jitter. */ /* Enable compare match timer 2 and 3. */ MSTP( CMT2 ) = 0; MSTP( CMT3 ) = 0; /* Interrupt on compare match. */ CMT2.CMCR.BIT.CMIE = 1; /* Set the compare match value. */ CMT2.CMCOR = ( unsigned short ) ( ( ( configPERIPHERAL_CLOCK_HZ / timerINTERRUPT_FREQUENCY ) -1 ) / 8 ); /* Divide the PCLK by 8. */ CMT2.CMCR.BIT.CKS = 0; CMT3.CMCR.BIT.CKS = 0; /* Enable the interrupt... */ _IEN( _CMT2_CMI2 ) = 1; /* ...and set its priority to the maximum possible, this is above the priority set by configMAX_SYSCALL_INTERRUPT_PRIORITY so will nest. */ _IPR( _CMT2_CMI2 ) = timerHIGHEST_PRIORITY; /* Start the timers. */ CMT.CMSTR1.BIT.STR2 = 1; CMT.CMSTR1.BIT.STR3 = 1; } /*-----------------------------------------------------------*/ #pragma interrupt ( prvTimer2IntHandler( vect = _VECT( _CMT2_CMI2 ), enable ) ) static void prvTimer2IntHandler( void ) { volatile unsigned short usCurrentCount; static unsigned short usMaxCount = 0; static unsigned long ulErrorCount = 0UL; /* We use the timer 1 counter value to measure the clock cycles between the timer 0 interrupts. First stop the clock. */ CMT.CMSTR1.BIT.STR3 = 0; nop(); nop(); usCurrentCount = timerTIMER_3_COUNT_VALUE; /* Is this the largest count we have measured yet? */ if( usCurrentCount > usMaxCount ) { if( usCurrentCount > timerEXPECTED_DIFFERENCE_VALUE ) { usMaxJitter = usCurrentCount - timerEXPECTED_DIFFERENCE_VALUE; } else { /* This should not happen! */ ulErrorCount++; } usMaxCount = usCurrentCount; } /* Used to generate the run time stats. */ ulHighFrequencyTickCount++; /* Clear the timer. */ timerTIMER_3_COUNT_VALUE = 0; /* Then start the clock again. */ CMT.CMSTR1.BIT.STR3 = 1; }