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/*
FreeRTOS V7.4.1 - Copyright (C) 2013 Real Time Engineers Ltd.
FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
***************************************************************************
* *
* FreeRTOS tutorial books are available in pdf and paperback. *
* Complete, revised, and edited pdf reference manuals are also *
* available. *
* *
* Purchasing FreeRTOS documentation will not only help you, by *
* ensuring you get running as quickly as possible and with an *
* in-depth knowledge of how to use FreeRTOS, it will also help *
* the FreeRTOS project to continue with its mission of providing *
* professional grade, cross platform, de facto standard solutions *
* for microcontrollers - completely free of charge! *
* *
* >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
* *
* Thank you for using FreeRTOS, and thank you for your support! *
* *
***************************************************************************
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. See the GNU General Public License for more
details. You should have received a copy of the GNU General Public License
and the FreeRTOS license exception along with FreeRTOS; if not it can be
viewed here: http://www.freertos.org/a00114.html and also obtained by
writing to Real Time Engineers Ltd., contact details for whom are available
on the FreeRTOS WEB site.
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 *
* *
***************************************************************************
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license and Real Time Engineers Ltd. contact details.
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including FreeRTOS+Trace - an indispensable productivity tool, and our new
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engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
*/
/*
Changes from V4.2.1
+ Introduced the configKERNEL_INTERRUPT_PRIORITY definition.
*/
/*-----------------------------------------------------------
* Implementation of functions defined in portable.h for the PIC24 port.
*----------------------------------------------------------*/
/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"
/* Hardware specifics. */
#define portBIT_SET 1
#define portTIMER_PRESCALE 8
#define portINITIAL_SR 0
/* Defined for backward compatability with project created prior to
FreeRTOS.org V4.3.0. */
#ifndef configKERNEL_INTERRUPT_PRIORITY
#define configKERNEL_INTERRUPT_PRIORITY 1
#endif
/* The program counter is only 23 bits. */
#define portUNUSED_PR_BITS 0x7f
/* Records the nesting depth of calls to portENTER_CRITICAL(). */
unsigned portBASE_TYPE uxCriticalNesting = 0xef;
#if configKERNEL_INTERRUPT_PRIORITY != 1
#error If configKERNEL_INTERRUPT_PRIORITY is not 1 then the #32 in the following macros needs changing to equal the portINTERRUPT_BITS value, which is ( configKERNEL_INTERRUPT_PRIORITY << 5 )
#endif
#ifdef MPLAB_PIC24_PORT
#ifdef __HAS_EDS__
#define portRESTORE_CONTEXT() \
asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
"MOV [W0], W15 \n" \
"POP W0 \n" /* Restore the critical nesting counter for the task. */ \
"MOV W0, _uxCriticalNesting \n" \
"POP DSWPAG \n" \
"POP DSRPAG \n" \
"POP CORCON \n" \
"POP TBLPAG \n" \
"POP RCOUNT \n" /* Restore the registers from the stack. */ \
"POP W14 \n" \
"POP.D W12 \n" \
"POP.D W10 \n" \
"POP.D W8 \n" \
"POP.D W6 \n" \
"POP.D W4 \n" \
"POP.D W2 \n" \
"POP.D W0 \n" \
"POP SR " );
#else /* __HAS_EDS__ */
#define portRESTORE_CONTEXT() \
asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
"MOV [W0], W15 \n" \
"POP W0 \n" /* Restore the critical nesting counter for the task. */ \
"MOV W0, _uxCriticalNesting \n" \
"POP PSVPAG \n" \
"POP CORCON \n" \
"POP TBLPAG \n" \
"POP RCOUNT \n" /* Restore the registers from the stack. */ \
"POP W14 \n" \
"POP.D W12 \n" \
"POP.D W10 \n" \
"POP.D W8 \n" \
"POP.D W6 \n" \
"POP.D W4 \n" \
"POP.D W2 \n" \
"POP.D W0 \n" \
"POP SR " );
#endif /* __HAS_EDS__ */
#endif /* MPLAB_PIC24_PORT */
#ifdef MPLAB_DSPIC_PORT
#define portRESTORE_CONTEXT() \
asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \
"MOV [W0], W15 \n" \
"POP W0 \n" /* Restore the critical nesting counter for the task. */ \
"MOV W0, _uxCriticalNesting \n" \
"POP PSVPAG \n" \
"POP CORCON \n" \
"POP DOENDH \n" \
"POP DOENDL \n" \
"POP DOSTARTH \n" \
"POP DOSTARTL \n" \
"POP DCOUNT \n" \
"POP ACCBU \n" \
"POP ACCBH \n" \
"POP ACCBL \n" \
"POP ACCAU \n" \
"POP ACCAH \n" \
"POP ACCAL \n" \
"POP TBLPAG \n" \
"POP RCOUNT \n" /* Restore the registers from the stack. */ \
"POP W14 \n" \
"POP.D W12 \n" \
"POP.D W10 \n" \
"POP.D W8 \n" \
"POP.D W6 \n" \
"POP.D W4 \n" \
"POP.D W2 \n" \
"POP.D W0 \n" \
"POP SR " );
#endif /* MPLAB_DSPIC_PORT */
/*
* Setup the timer used to generate the tick interrupt.
*/
static void prvSetupTimerInterrupt( void );
/*
* See header file for description.
*/
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
{
unsigned short usCode;
portBASE_TYPE i;
const portSTACK_TYPE xInitialStack[] =
{
0x1111, /* W1 */
0x2222, /* W2 */
0x3333, /* W3 */
0x4444, /* W4 */
0x5555, /* W5 */
0x6666, /* W6 */
0x7777, /* W7 */
0x8888, /* W8 */
0x9999, /* W9 */
0xaaaa, /* W10 */
0xbbbb, /* W11 */
0xcccc, /* W12 */
0xdddd, /* W13 */
0xeeee, /* W14 */
0xcdce, /* RCOUNT */
0xabac, /* TBLPAG */
/* dsPIC specific registers. */
#ifdef MPLAB_DSPIC_PORT
0x0202, /* ACCAL */
0x0303, /* ACCAH */
0x0404, /* ACCAU */
0x0505, /* ACCBL */
0x0606, /* ACCBH */
0x0707, /* ACCBU */
0x0808, /* DCOUNT */
0x090a, /* DOSTARTL */
0x1010, /* DOSTARTH */
0x1110, /* DOENDL */
0x1212, /* DOENDH */
#endif
};
/* Setup the stack as if a yield had occurred.
Save the low bytes of the program counter. */
usCode = ( unsigned short ) pxCode;
*pxTopOfStack = ( portSTACK_TYPE ) usCode;
pxTopOfStack++;
/* Save the high byte of the program counter. This will always be zero
here as it is passed in a 16bit pointer. If the address is greater than
16 bits then the pointer will point to a jump table. */
*pxTopOfStack = ( portSTACK_TYPE ) 0;
pxTopOfStack++;
/* Status register with interrupts enabled. */
*pxTopOfStack = portINITIAL_SR;
pxTopOfStack++;
/* Parameters are passed in W0. */
*pxTopOfStack = ( portSTACK_TYPE ) pvParameters;
pxTopOfStack++;
for( i = 0; i < ( sizeof( xInitialStack ) / sizeof( portSTACK_TYPE ) ); i++ )
{
*pxTopOfStack = xInitialStack[ i ];
pxTopOfStack++;
}
*pxTopOfStack = CORCON;
pxTopOfStack++;
#if defined(__HAS_EDS__)
*pxTopOfStack = DSRPAG;
pxTopOfStack++;
*pxTopOfStack = DSWPAG;
pxTopOfStack++;
#else /* __HAS_EDS__ */
*pxTopOfStack = PSVPAG;
pxTopOfStack++;
#endif /* __HAS_EDS__ */
/* Finally the critical nesting depth. */
*pxTopOfStack = 0x00;
pxTopOfStack++;
return pxTopOfStack;
}
/*-----------------------------------------------------------*/
portBASE_TYPE xPortStartScheduler( void )
{
/* Setup a timer for the tick ISR. */
prvSetupTimerInterrupt();
/* Restore the context of the first task to run. */
portRESTORE_CONTEXT();
/* Simulate the end of the yield function. */
asm volatile ( "return" );
/* Should not reach here. */
return pdTRUE;
}
/*-----------------------------------------------------------*/
void vPortEndScheduler( void )
{
/* It is unlikely that the scheduler for the PIC port will get stopped
once running. If required disable the tick interrupt here, then return
to xPortStartScheduler(). */
}
/*-----------------------------------------------------------*/
/*
* Setup a timer for a regular tick.
*/
static void prvSetupTimerInterrupt( void )
{
const unsigned long ulCompareMatch = ( ( configCPU_CLOCK_HZ / portTIMER_PRESCALE ) / configTICK_RATE_HZ ) - 1;
/* Prescale of 8. */
T1CON = 0;
TMR1 = 0;
PR1 = ( unsigned short ) ulCompareMatch;
/* Setup timer 1 interrupt priority. */
IPC0bits.T1IP = configKERNEL_INTERRUPT_PRIORITY;
/* Clear the interrupt as a starting condition. */
IFS0bits.T1IF = 0;
/* Enable the interrupt. */
IEC0bits.T1IE = 1;
/* Setup the prescale value. */
T1CONbits.TCKPS0 = 1;
T1CONbits.TCKPS1 = 0;
/* Start the timer. */
T1CONbits.TON = 1;
}
/*-----------------------------------------------------------*/
void vPortEnterCritical( void )
{
portDISABLE_INTERRUPTS();
uxCriticalNesting++;
}
/*-----------------------------------------------------------*/
void vPortExitCritical( void )
{
uxCriticalNesting--;
if( uxCriticalNesting == 0 )
{
portENABLE_INTERRUPTS();
}
}
/*-----------------------------------------------------------*/
void __attribute__((__interrupt__, auto_psv)) _T1Interrupt( void )
{
/* Clear the timer interrupt. */
IFS0bits.T1IF = 0;
vTaskIncrementTick();
#if configUSE_PREEMPTION == 1
portYIELD();
#endif
}