| /*
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| FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 Richard Barry.
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|
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| This file is part of the FreeRTOS.org distribution.
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|
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| FreeRTOS.org is free software; you can redistribute it and/or modify it
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| under the terms of the GNU General Public License (version 2) as published
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| by the Free Software Foundation and modified by the FreeRTOS exception.
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|
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| FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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| more details.
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|
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| You should have received a copy of the GNU General Public License along
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| with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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| Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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|
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| A special exception to the GPL is included to allow you to distribute a
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| combined work that includes FreeRTOS.org without being obliged to provide
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| the source code for any proprietary components. See the licensing section
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| of http://www.FreeRTOS.org for full details.
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|
|
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| ***************************************************************************
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| * *
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| * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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| * *
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| * This is a concise, step by step, 'hands on' guide that describes both *
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| * general multitasking concepts and FreeRTOS specifics. It presents and *
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| * explains numerous examples that are written using the FreeRTOS API. *
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| * Full source code for all the examples is provided in an accompanying *
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| * .zip file. *
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| * *
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| ***************************************************************************
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|
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| 1 tab == 4 spaces!
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| Please ensure to read the configuration and relevant port sections of the
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| online documentation.
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| http://www.FreeRTOS.org - Documentation, latest information, license and
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| contact details.
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|
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| http://www.SafeRTOS.com - A version that is certified for use in safety
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| critical systems.
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|
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| http://www.OpenRTOS.com - Commercial support, development, porting,
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| licensing and training services.
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| */
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|
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| /* High speed timer test as described in main.c. */
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|
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| /* Scheduler includes. */
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| #include "FreeRTOS.h"
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|
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| /* Library includes. */
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| #include "hw_ints.h"
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| #include "hw_memmap.h"
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| #include "hw_types.h"
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| #include "interrupt.h"
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| #include "sysctl.h"
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| #include "lmi_timer.h"
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|
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| /* The set frequency of the interrupt. Deviations from this are measured as
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| the jitter. */
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| #define timerINTERRUPT_FREQUENCY ( 20000UL )
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|
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| /* The expected time between each of the timer interrupts - if the jitter was
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| zero. */
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| #define timerEXPECTED_DIFFERENCE_VALUE ( configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY )
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|
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| /* The highest available interrupt priority. */
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| #define timerHIGHEST_PRIORITY ( 0 )
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|
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| /* Misc defines. */
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| #define timerMAX_32BIT_VALUE ( 0xffffffffUL )
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| #define timerTIMER_1_COUNT_VALUE ( * ( ( unsigned long * ) ( TIMER1_BASE + 0x48 ) ) )
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|
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| /*-----------------------------------------------------------*/
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|
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| /* Interrupt handler in which the jitter is measured. */
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| void Timer0IntHandler( void );
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|
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| /* Stores the value of the maximum recorded jitter between interrupts. */
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| volatile unsigned portLONG ulMaxJitter = 0UL;
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|
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| /* Counts the total number of times that the high frequency timer has 'ticked'.
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| This value is used by the run time stats function to work out what percentage
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| of CPU time each task is taking. */ |
| volatile unsigned portLONG ulHighFrequencyTimerTicks = 0UL;
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| /*-----------------------------------------------------------*/
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| void vSetupHighFrequencyTimer( void )
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| {
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| unsigned long ulFrequency;
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|
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| /* Timer zero is used to generate the interrupts, and timer 1 is used
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| to measure the jitter. */
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| SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER0 );
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| SysCtlPeripheralEnable( SYSCTL_PERIPH_TIMER1 );
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| TimerConfigure( TIMER0_BASE, TIMER_CFG_32_BIT_PER );
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| TimerConfigure( TIMER1_BASE, TIMER_CFG_32_BIT_PER );
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| /* Set the timer interrupt to be above the kernel - highest. */
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| IntPrioritySet( INT_TIMER0A, timerHIGHEST_PRIORITY );
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| /* Just used to measure time. */
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| TimerLoadSet(TIMER1_BASE, TIMER_A, timerMAX_32BIT_VALUE );
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| /* Ensure interrupts do not start until the scheduler is running. */
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| portDISABLE_INTERRUPTS();
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|
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| /* The rate at which the timer will interrupt. */
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| ulFrequency = configCPU_CLOCK_HZ / timerINTERRUPT_FREQUENCY;
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| TimerLoadSet( TIMER0_BASE, TIMER_A, ulFrequency );
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| IntEnable( INT_TIMER0A );
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| TimerIntEnable( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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| /* Enable both timers. */
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| TimerEnable( TIMER0_BASE, TIMER_A );
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| TimerEnable( TIMER1_BASE, TIMER_A );
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| }
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| /*-----------------------------------------------------------*/
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|
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| void Timer0IntHandler( void )
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| {
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| unsigned portLONG ulDifference;
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| volatile unsigned portLONG ulCurrentCount;
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| static unsigned portLONG ulMaxDifference = 0, ulLastCount = 0;
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|
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| /* We use the timer 1 counter value to measure the clock cycles between
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| the timer 0 interrupts. */
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| ulCurrentCount = timerTIMER_1_COUNT_VALUE;
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| TimerIntClear( TIMER0_BASE, TIMER_TIMA_TIMEOUT );
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| if( ulCurrentCount < ulLastCount )
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| {
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| /* How many times has timer 1 counted since the last interrupt? */
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| ulDifference = ulLastCount - ulCurrentCount;
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|
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| /* Is this the largest difference we have measured yet? */
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| if( ulDifference > ulMaxDifference )
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| {
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| ulMaxDifference = ulDifference;
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| ulMaxJitter = ulMaxDifference - timerEXPECTED_DIFFERENCE_VALUE;
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| }
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| }
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| ulLastCount = ulCurrentCount;
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|
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| /* Keep a count of the total number of 20KHz ticks. This is used by the
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| run time stats functionality to calculate how much CPU time is used by
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| each task. */
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| ulHighFrequencyTimerTicks++; |
| }
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