| /* | |
| FreeRTOS V7.4.0 - 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 itcan 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 * | |
| * * | |
| *************************************************************************** | |
| 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, and our new | |
| fully thread aware and reentrant UDP/IP stack. | |
| http://www.OpenRTOS.com - 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.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. | |
| */ | |
| /*----------------------------------------------------------- | |
| * Implementation of functions defined in portable.h for the ARM CM0 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 portMIN_INTERRUPT_PRIORITY ( 255UL ) | |
| #define portNVIC_PENDSV_PRI ( portMIN_INTERRUPT_PRIORITY << 16UL ) | |
| #define portNVIC_SYSTICK_PRI ( portMIN_INTERRUPT_PRIORITY << 24UL ) | |
| /* 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 -= 6; /* LR, R12, R3..R1 */ | |
| *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */ | |
| pxTopOfStack -= 8; /* R11..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 CM0 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. | |
| */ | |
| static 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; | |
| } | |
| /*-----------------------------------------------------------*/ | |