/* | |
FreeRTOS V7.2.0 - Copyright (C) 2012 Real Time Engineers Ltd. | |
*************************************************************************** | |
* * | |
* 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 Richard Barry, 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 * | |
* * | |
*************************************************************************** | |
http://www.FreeRTOS.org - Documentation, training, latest information, | |
license and contact details. | |
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products, | |
including FreeRTOS+Trace - an indispensable productivity tool. | |
Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell | |
the code with commercial support, indemnification, and middleware, under | |
the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also | |
provide a safety engineered and independently SIL3 certified version under | |
the SafeRTOS brand: http://www.SafeRTOS.com. | |
*/ | |
/* | |
Changes between V1.2.4 and V1.2.5 | |
+ Introduced portGLOBAL_INTERRUPT_FLAG definition to test the global | |
interrupt flag setting. Using the two bits defined within | |
portINITAL_INTERRUPT_STATE was causing the w register to get clobbered | |
before the test was performed. | |
Changes from V1.2.5 | |
+ Set the interrupt vector address to 0x08. Previously it was at the | |
incorrect address for compatibility mode of 0x18. | |
Changes from V2.1.1 | |
+ PCLATU and PCLATH are now saved as part of the context. This allows | |
function pointers to be used within tasks. Thanks to Javier Espeche | |
for the enhancement. | |
Changes from V2.3.1 | |
+ TABLAT is now saved as part of the task context. | |
Changes from V3.2.0 | |
+ TBLPTRU is now initialised to zero as the MPLAB compiler expects this | |
value and does not write to the register. | |
*/ | |
/* Scheduler include files. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
/* MPLAB library include file. */ | |
#include "timers.h" | |
/*----------------------------------------------------------- | |
* Implementation of functions defined in portable.h for the PIC port. | |
*----------------------------------------------------------*/ | |
/* Hardware setup for tick. */ | |
#define portTIMER_FOSC_SCALE ( ( unsigned long ) 4 ) | |
/* Initial interrupt enable state for newly created tasks. This value is | |
copied into INTCON when a task switches in for the first time. */ | |
#define portINITAL_INTERRUPT_STATE 0xc0 | |
/* Just the bit within INTCON for the global interrupt flag. */ | |
#define portGLOBAL_INTERRUPT_FLAG 0x80 | |
/* Constant used for context switch macro when we require the interrupt | |
enable state to be unchanged when the interrupted task is switched back in. */ | |
#define portINTERRUPTS_UNCHANGED 0x00 | |
/* Some memory areas get saved as part of the task context. These memory | |
area's get used by the compiler for temporary storage, especially when | |
performing mathematical operations, or when using 32bit data types. This | |
constant defines the size of memory area which must be saved. */ | |
#define portCOMPILER_MANAGED_MEMORY_SIZE ( ( unsigned char ) 0x13 ) | |
/* We require the address of the pxCurrentTCB variable, but don't want to know | |
any details of its type. */ | |
typedef void tskTCB; | |
extern volatile tskTCB * volatile pxCurrentTCB; | |
/* IO port constants. */ | |
#define portBIT_SET ( ( unsigned char ) 1 ) | |
#define portBIT_CLEAR ( ( unsigned char ) 0 ) | |
/* | |
* The serial port ISR's are defined in serial.c, but are called from portable | |
* as they use the same vector as the tick ISR. | |
*/ | |
void vSerialTxISR( void ); | |
void vSerialRxISR( void ); | |
/* | |
* Perform hardware setup to enable ticks. | |
*/ | |
static void prvSetupTimerInterrupt( void ); | |
/* | |
* ISR to maintain the tick, and perform tick context switches if the | |
* preemptive scheduler is being used. | |
*/ | |
static void prvTickISR( void ); | |
/* | |
* ISR placed on the low priority vector. This calls the appropriate ISR for | |
* the actual interrupt. | |
*/ | |
static void prvLowInterrupt( void ); | |
/* | |
* Macro that pushes all the registers that make up the context of a task onto | |
* the stack, then saves the new top of stack into the TCB. | |
* | |
* If this is called from an ISR then the interrupt enable bits must have been | |
* set for the ISR to ever get called. Therefore we want to save the INTCON | |
* register with the enable bits forced to be set - and ucForcedInterruptFlags | |
* must contain these bit settings. This means the interrupts will again be | |
* enabled when the interrupted task is switched back in. | |
* | |
* If this is called from a manual context switch (i.e. from a call to yield), | |
* then we want to save the INTCON so it is restored with its current state, | |
* and ucForcedInterruptFlags must be 0. This allows a yield from within | |
* a critical section. | |
* | |
* The compiler uses some locations at the bottom of the memory for temporary | |
* storage during math and other computations. This is especially true if | |
* 32bit data types are utilised (as they are by the scheduler). The .tmpdata | |
* and MATH_DATA sections have to be stored in there entirety as part of a task | |
* context. This macro stores from data address 0x00 to | |
* portCOMPILER_MANAGED_MEMORY_SIZE. This is sufficient for the demo | |
* applications but you should check the map file for your project to ensure | |
* this is sufficient for your needs. It is not clear whether this size is | |
* fixed for all compilations or has the potential to be program specific. | |
*/ | |
#define portSAVE_CONTEXT( ucForcedInterruptFlags ) \ | |
{ \ | |
_asm \ | |
/* Save the status and WREG registers first, as these will get modified \ | |
by the operations below. */ \ | |
MOVFF WREG, PREINC1 \ | |
MOVFF STATUS, PREINC1 \ | |
/* Save the INTCON register with the appropriate bits forced if \ | |
necessary - as described above. */ \ | |
MOVFF INTCON, WREG \ | |
IORLW ucForcedInterruptFlags \ | |
MOVFF WREG, PREINC1 \ | |
_endasm \ | |
\ | |
portDISABLE_INTERRUPTS(); \ | |
\ | |
_asm \ | |
/* Store the necessary registers to the stack. */ \ | |
MOVFF BSR, PREINC1 \ | |
MOVFF FSR2L, PREINC1 \ | |
MOVFF FSR2H, PREINC1 \ | |
MOVFF FSR0L, PREINC1 \ | |
MOVFF FSR0H, PREINC1 \ | |
MOVFF TABLAT, PREINC1 \ | |
MOVFF TBLPTRU, PREINC1 \ | |
MOVFF TBLPTRH, PREINC1 \ | |
MOVFF TBLPTRL, PREINC1 \ | |
MOVFF PRODH, PREINC1 \ | |
MOVFF PRODL, PREINC1 \ | |
MOVFF PCLATU, PREINC1 \ | |
MOVFF PCLATH, PREINC1 \ | |
/* Store the .tempdata and MATH_DATA areas as described above. */ \ | |
CLRF FSR0L, 0 \ | |
CLRF FSR0H, 0 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF POSTINC0, PREINC1 \ | |
MOVFF INDF0, PREINC1 \ | |
MOVFF FSR0L, PREINC1 \ | |
MOVFF FSR0H, PREINC1 \ | |
/* Store the hardware stack pointer in a temp register before we \ | |
modify it. */ \ | |
MOVFF STKPTR, FSR0L \ | |
_endasm \ | |
\ | |
/* Store each address from the hardware stack. */ \ | |
while( STKPTR > ( unsigned char ) 0 ) \ | |
{ \ | |
_asm \ | |
MOVFF TOSL, PREINC1 \ | |
MOVFF TOSH, PREINC1 \ | |
MOVFF TOSU, PREINC1 \ | |
POP \ | |
_endasm \ | |
} \ | |
\ | |
_asm \ | |
/* Store the number of addresses on the hardware stack (from the \ | |
temporary register). */ \ | |
MOVFF FSR0L, PREINC1 \ | |
MOVF PREINC1, 1, 0 \ | |
_endasm \ | |
\ | |
/* Save the new top of the software stack in the TCB. */ \ | |
_asm \ | |
MOVFF pxCurrentTCB, FSR0L \ | |
MOVFF pxCurrentTCB + 1, FSR0H \ | |
MOVFF FSR1L, POSTINC0 \ | |
MOVFF FSR1H, POSTINC0 \ | |
_endasm \ | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* This is the reverse of portSAVE_CONTEXT. See portSAVE_CONTEXT for more | |
* details. | |
*/ | |
#define portRESTORE_CONTEXT() \ | |
{ \ | |
_asm \ | |
/* Set FSR0 to point to pxCurrentTCB->pxTopOfStack. */ \ | |
MOVFF pxCurrentTCB, FSR0L \ | |
MOVFF pxCurrentTCB + 1, FSR0H \ | |
\ | |
/* De-reference FSR0 to set the address it holds into FSR1. \ | |
(i.e. *( pxCurrentTCB->pxTopOfStack ) ). */ \ | |
MOVFF POSTINC0, FSR1L \ | |
MOVFF POSTINC0, FSR1H \ | |
\ | |
/* How many return addresses are there on the hardware stack? Discard \ | |
the first byte as we are pointing to the next free space. */ \ | |
MOVFF POSTDEC1, FSR0L \ | |
MOVFF POSTDEC1, FSR0L \ | |
_endasm \ | |
\ | |
/* Fill the hardware stack from our software stack. */ \ | |
STKPTR = 0; \ | |
\ | |
while( STKPTR < FSR0L ) \ | |
{ \ | |
_asm \ | |
PUSH \ | |
MOVF POSTDEC1, 0, 0 \ | |
MOVWF TOSU, 0 \ | |
MOVF POSTDEC1, 0, 0 \ | |
MOVWF TOSH, 0 \ | |
MOVF POSTDEC1, 0, 0 \ | |
MOVWF TOSL, 0 \ | |
_endasm \ | |
} \ | |
\ | |
_asm \ | |
/* Restore the .tmpdata and MATH_DATA memory. */ \ | |
MOVFF POSTDEC1, FSR0H \ | |
MOVFF POSTDEC1, FSR0L \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, POSTDEC0 \ | |
MOVFF POSTDEC1, INDF0 \ | |
/* Restore the other registers forming the tasks context. */ \ | |
MOVFF POSTDEC1, PCLATH \ | |
MOVFF POSTDEC1, PCLATU \ | |
MOVFF POSTDEC1, PRODL \ | |
MOVFF POSTDEC1, PRODH \ | |
MOVFF POSTDEC1, TBLPTRL \ | |
MOVFF POSTDEC1, TBLPTRH \ | |
MOVFF POSTDEC1, TBLPTRU \ | |
MOVFF POSTDEC1, TABLAT \ | |
MOVFF POSTDEC1, FSR0H \ | |
MOVFF POSTDEC1, FSR0L \ | |
MOVFF POSTDEC1, FSR2H \ | |
MOVFF POSTDEC1, FSR2L \ | |
MOVFF POSTDEC1, BSR \ | |
/* The next byte is the INTCON register. Read this into WREG as some \ | |
manipulation is required. */ \ | |
MOVFF POSTDEC1, WREG \ | |
_endasm \ | |
\ | |
/* From the INTCON register, only the interrupt enable bits form part \ | |
of the tasks context. It is perfectly legitimate for another task to \ | |
have modified any other bits. We therefore only restore the top two bits. \ | |
*/ \ | |
if( WREG & portGLOBAL_INTERRUPT_FLAG ) \ | |
{ \ | |
_asm \ | |
MOVFF POSTDEC1, STATUS \ | |
MOVFF POSTDEC1, WREG \ | |
/* Return enabling interrupts. */ \ | |
RETFIE 0 \ | |
_endasm \ | |
} \ | |
else \ | |
{ \ | |
_asm \ | |
MOVFF POSTDEC1, STATUS \ | |
MOVFF POSTDEC1, WREG \ | |
/* Return without effecting interrupts. The context may have \ | |
been saved from a critical region. */ \ | |
RETURN 0 \ | |
_endasm \ | |
} \ | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* See header file for description. | |
*/ | |
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters ) | |
{ | |
unsigned long ulAddress; | |
unsigned char ucBlock; | |
/* Place a few bytes of known values on the bottom of the stack. | |
This is just useful for debugging. */ | |
*pxTopOfStack = 0x11; | |
pxTopOfStack++; | |
*pxTopOfStack = 0x22; | |
pxTopOfStack++; | |
*pxTopOfStack = 0x33; | |
pxTopOfStack++; | |
/* Simulate how the stack would look after a call to vPortYield() generated | |
by the compiler. | |
First store the function parameters. This is where the task will expect to | |
find them when it starts running. */ | |
ulAddress = ( unsigned long ) pvParameters; | |
*pxTopOfStack = ( portSTACK_TYPE ) ( ulAddress & ( unsigned long ) 0x00ff ); | |
pxTopOfStack++; | |
ulAddress >>= 8; | |
*pxTopOfStack = ( portSTACK_TYPE ) ( ulAddress & ( unsigned long ) 0x00ff ); | |
pxTopOfStack++; | |
/* Next we just leave a space. When a context is saved the stack pointer | |
is incremented before it is used so as not to corrupt whatever the stack | |
pointer is actually pointing to. This is especially necessary during | |
function epilogue code generated by the compiler. */ | |
*pxTopOfStack = 0x44; | |
pxTopOfStack++; | |
/* Next are all the registers that form part of the task context. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x66; /* WREG. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xcc; /* Status. */ | |
pxTopOfStack++; | |
/* INTCON is saved with interrupts enabled. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) portINITAL_INTERRUPT_STATE; /* INTCON */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x11; /* BSR. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x22; /* FSR2L. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x33; /* FSR2H. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x44; /* FSR0L. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x55; /* FSR0H. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x66; /* TABLAT. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x00; /* TBLPTRU. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x88; /* TBLPTRUH. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x99; /* TBLPTRUL. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xaa; /* PRODH. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xbb; /* PRODL. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x00; /* PCLATU. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x00; /* PCLATH. */ | |
pxTopOfStack++; | |
/* Next the .tmpdata and MATH_DATA sections. */ | |
for( ucBlock = 0; ucBlock <= portCOMPILER_MANAGED_MEMORY_SIZE; ucBlock++ ) | |
{ | |
*pxTopOfStack = ( portSTACK_TYPE ) ucBlock; | |
*pxTopOfStack++; | |
} | |
/* Store the top of the global data section. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) portCOMPILER_MANAGED_MEMORY_SIZE; /* Low. */ | |
pxTopOfStack++; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x00; /* High. */ | |
pxTopOfStack++; | |
/* The only function return address so far is the address of the | |
task. */ | |
ulAddress = ( unsigned long ) pxCode; | |
/* TOS low. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) ( ulAddress & ( unsigned long ) 0x00ff ); | |
pxTopOfStack++; | |
ulAddress >>= 8; | |
/* TOS high. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) ( ulAddress & ( unsigned long ) 0x00ff ); | |
pxTopOfStack++; | |
ulAddress >>= 8; | |
/* TOS even higher. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) ( ulAddress & ( unsigned long ) 0x00ff ); | |
pxTopOfStack++; | |
/* Store the number of return addresses on the hardware stack - so far only | |
the address of the task entry point. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) 1; | |
pxTopOfStack++; | |
return pxTopOfStack; | |
} | |
/*-----------------------------------------------------------*/ | |
portBASE_TYPE xPortStartScheduler( void ) | |
{ | |
/* Setup a timer for the tick ISR is using the preemptive scheduler. */ | |
prvSetupTimerInterrupt(); | |
/* Restore the context of the first task to run. */ | |
portRESTORE_CONTEXT(); | |
/* Should not get here. Use the function name to stop compiler warnings. */ | |
( void ) prvLowInterrupt; | |
( void ) prvTickISR; | |
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(). */ | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* Manual context switch. This is similar to the tick context switch, | |
* but does not increment the tick count. It must be identical to the | |
* tick context switch in how it stores the stack of a task. | |
*/ | |
void vPortYield( void ) | |
{ | |
/* This can get called with interrupts either enabled or disabled. We | |
will save the INTCON register with the interrupt enable bits unmodified. */ | |
portSAVE_CONTEXT( portINTERRUPTS_UNCHANGED ); | |
/* Switch to the highest priority task that is ready to run. */ | |
vTaskSwitchContext(); | |
/* Start executing the task we have just switched to. */ | |
portRESTORE_CONTEXT(); | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* Vector for ISR. Nothing here must alter any registers! | |
*/ | |
#pragma code high_vector=0x08 | |
static void prvLowInterrupt( void ) | |
{ | |
/* Was the interrupt the tick? */ | |
if( PIR1bits.CCP1IF ) | |
{ | |
_asm | |
goto prvTickISR | |
_endasm | |
} | |
/* Was the interrupt a byte being received? */ | |
if( PIR1bits.RCIF ) | |
{ | |
_asm | |
goto vSerialRxISR | |
_endasm | |
} | |
/* Was the interrupt the Tx register becoming empty? */ | |
if( PIR1bits.TXIF ) | |
{ | |
if( PIE1bits.TXIE ) | |
{ | |
_asm | |
goto vSerialTxISR | |
_endasm | |
} | |
} | |
} | |
#pragma code | |
/*-----------------------------------------------------------*/ | |
/* | |
* ISR for the tick. | |
* This increments the tick count and, if using the preemptive scheduler, | |
* performs a context switch. This must be identical to the manual | |
* context switch in how it stores the context of a task. | |
*/ | |
static void prvTickISR( void ) | |
{ | |
/* Interrupts must have been enabled for the ISR to fire, so we have to | |
save the context with interrupts enabled. */ | |
portSAVE_CONTEXT( portGLOBAL_INTERRUPT_FLAG ); | |
PIR1bits.CCP1IF = 0; | |
/* Maintain the tick count. */ | |
vTaskIncrementTick(); | |
#if configUSE_PREEMPTION == 1 | |
{ | |
/* Switch to the highest priority task that is ready to run. */ | |
vTaskSwitchContext(); | |
} | |
#endif | |
portRESTORE_CONTEXT(); | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* Setup a timer for a regular tick. | |
*/ | |
static void prvSetupTimerInterrupt( void ) | |
{ | |
const unsigned long ulConstCompareValue = ( ( configCPU_CLOCK_HZ / portTIMER_FOSC_SCALE ) / configTICK_RATE_HZ ); | |
unsigned long ulCompareValue; | |
unsigned char ucByte; | |
/* Interrupts are disabled when this function is called. | |
Setup CCP1 to provide the tick interrupt using a compare match on timer | |
1. | |
Clear the time count then setup timer. */ | |
TMR1H = ( unsigned char ) 0x00; | |
TMR1L = ( unsigned char ) 0x00; | |
/* Set the compare match value. */ | |
ulCompareValue = ulConstCompareValue; | |
CCPR1L = ( unsigned char ) ( ulCompareValue & ( unsigned long ) 0xff ); | |
ulCompareValue >>= ( unsigned long ) 8; | |
CCPR1H = ( unsigned char ) ( ulCompareValue & ( unsigned long ) 0xff ); | |
CCP1CONbits.CCP1M0 = portBIT_SET; /*< Compare match mode. */ | |
CCP1CONbits.CCP1M1 = portBIT_SET; /*< Compare match mode. */ | |
CCP1CONbits.CCP1M2 = portBIT_CLEAR; /*< Compare match mode. */ | |
CCP1CONbits.CCP1M3 = portBIT_SET; /*< Compare match mode. */ | |
PIE1bits.CCP1IE = portBIT_SET; /*< Interrupt enable. */ | |
/* We are only going to use the global interrupt bit, so set the peripheral | |
bit to true. */ | |
INTCONbits.GIEL = portBIT_SET; | |
/* Provided library function for setting up the timer that will produce the | |
tick. */ | |
OpenTimer1( T1_16BIT_RW & T1_SOURCE_INT & T1_PS_1_1 & T1_CCP1_T3_CCP2 ); | |
} | |