/* | |
FreeRTOS V7.0.2 - Copyright (C) 2011 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! | |
http://www.FreeRTOS.org - Documentation, latest information, license and | |
contact details. | |
http://www.SafeRTOS.com - A version that is certified for use in safety | |
critical systems. | |
http://www.OpenRTOS.com - Commercial support, development, porting, | |
licensing and training services. | |
*/ | |
/* | |
Change from V4.2.1: | |
+ Introduced usage of configKERNEL_INTERRUPT_PRIORITY macro to set the | |
interrupt priority used by the kernel. | |
*/ | |
/*----------------------------------------------------------- | |
* Implementation of functions defined in portable.h for the ARM CM3 port. | |
*----------------------------------------------------------*/ | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
/* Constants required to manipulate the NVIC. */ | |
#define portNVIC_SYSTICK_CTRL ( ( volatile unsigned long *) 0xe000e010 ) | |
#define portNVIC_SYSTICK_LOAD ( ( volatile unsigned long *) 0xe000e014 ) | |
#define portNVIC_INT_CTRL ( ( volatile unsigned long *) 0xe000ed04 ) | |
#define portNVIC_SYSPRI2 ( ( volatile unsigned long *) 0xe000ed20 ) | |
#define portNVIC_SYSTICK_CLK 0x00000004 | |
#define portNVIC_SYSTICK_INT 0x00000002 | |
#define portNVIC_SYSTICK_ENABLE 0x00000001 | |
#define portNVIC_PENDSVSET 0x10000000 | |
#define portNVIC_PENDSV_PRI ( ( ( unsigned long ) configKERNEL_INTERRUPT_PRIORITY ) << 16 ) | |
#define portNVIC_SYSTICK_PRI ( ( ( unsigned long ) configKERNEL_INTERRUPT_PRIORITY ) << 24 ) | |
/* Constants required to set up the initial stack. */ | |
#define portINITIAL_XPSR ( 0x01000000 ) | |
/* For backward compatibility, ensure configKERNEL_INTERRUPT_PRIORITY is | |
defined. The value 255 should also ensure backward compatibility. | |
FreeRTOS.org versions prior to V4.3.0 did not include this definition. */ | |
#ifndef configKERNEL_INTERRUPT_PRIORITY | |
#define configKERNEL_INTERRUPT_PRIORITY 0 | |
#endif | |
/* Each task maintains its own interrupt status in the critical nesting | |
variable. */ | |
static unsigned portBASE_TYPE uxCriticalNesting = 0xaaaaaaaa; | |
/* | |
* Setup the timer to generate the tick interrupts. | |
*/ | |
static void prvSetupTimerInterrupt( void ); | |
/* | |
* Exception handlers. | |
*/ | |
void xPortSysTickHandler( void ); | |
/* | |
* Start first task is a separate function so it can be tested in isolation. | |
*/ | |
extern void vPortStartFirstTask( void ); | |
/*-----------------------------------------------------------*/ | |
/* | |
* See header file for description. | |
*/ | |
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters ) | |
{ | |
/* Simulate the stack frame as it would be created by a context switch | |
interrupt. */ | |
pxTopOfStack--; /* Offset added to account for the way the MCU uses the stack on entry/exit of interrupts. */ | |
*pxTopOfStack = portINITIAL_XPSR; /* xPSR */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) pxCode; /* PC */ | |
pxTopOfStack--; | |
*pxTopOfStack = 0; /* LR */ | |
pxTopOfStack -= 5; /* R12, R3, R2 and R1. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */ | |
pxTopOfStack -= 8; /* R11, R10, R9, R8, R7, R6, R5 and R4. */ | |
return pxTopOfStack; | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* See header file for description. | |
*/ | |
portBASE_TYPE xPortStartScheduler( void ) | |
{ | |
/* Make PendSV and SysTick the lowest priority interrupts. */ | |
*(portNVIC_SYSPRI2) |= portNVIC_PENDSV_PRI; | |
*(portNVIC_SYSPRI2) |= portNVIC_SYSTICK_PRI; | |
/* Start the timer that generates the tick ISR. Interrupts are disabled | |
here already. */ | |
prvSetupTimerInterrupt(); | |
/* Initialise the critical nesting count ready for the first task. */ | |
uxCriticalNesting = 0; | |
/* Start the first task. */ | |
vPortStartFirstTask(); | |
/* Should not get here! */ | |
return 0; | |
} | |
/*-----------------------------------------------------------*/ | |
void vPortEndScheduler( void ) | |
{ | |
/* It is unlikely that the CM3 port will require this function as there | |
is nothing to return to. */ | |
} | |
/*-----------------------------------------------------------*/ | |
void vPortYieldFromISR( void ) | |
{ | |
/* Set a PendSV to request a context switch. */ | |
*(portNVIC_INT_CTRL) = portNVIC_PENDSVSET; | |
} | |
/*-----------------------------------------------------------*/ | |
void vPortEnterCritical( void ) | |
{ | |
portDISABLE_INTERRUPTS(); | |
uxCriticalNesting++; | |
} | |
/*-----------------------------------------------------------*/ | |
void vPortExitCritical( void ) | |
{ | |
uxCriticalNesting--; | |
if( uxCriticalNesting == 0 ) | |
{ | |
portENABLE_INTERRUPTS(); | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
void xPortSysTickHandler( void ) | |
{ | |
unsigned long ulDummy; | |
/* If using preemption, also force a context switch. */ | |
#if configUSE_PREEMPTION == 1 | |
*(portNVIC_INT_CTRL) = portNVIC_PENDSVSET; | |
#endif | |
ulDummy = portSET_INTERRUPT_MASK_FROM_ISR(); | |
{ | |
vTaskIncrementTick(); | |
} | |
portCLEAR_INTERRUPT_MASK_FROM_ISR( ulDummy ); | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* Setup the systick timer to generate the tick interrupts at the required | |
* frequency. | |
*/ | |
void prvSetupTimerInterrupt( void ) | |
{ | |
/* Configure SysTick to interrupt at the requested rate. */ | |
*(portNVIC_SYSTICK_LOAD) = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1UL; | |
*(portNVIC_SYSTICK_CTRL) = portNVIC_SYSTICK_CLK | portNVIC_SYSTICK_INT | portNVIC_SYSTICK_ENABLE; | |
} | |
/*-----------------------------------------------------------*/ | |