/*
FreeRTOS.org V4.2.1 - Copyright (C) 2003-2007 Richard Barry.
This file is part of the FreeRTOS.org distribution.
FreeRTOS.org is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FreeRTOS.org 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
along with FreeRTOS.org; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes FreeRTOS.org, without being obliged to provide
the source code for any proprietary components. See the licensing section
of http://www.FreeRTOS.org for full details of how and when the exception
can be applied.
***************************************************************************
See http://www.FreeRTOS.org for documentation, latest information, license
and contact details. Please ensure to read the configuration and relevant
port sections of the online documentation.
Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along
with commercial development and support options.
***************************************************************************
*/
#ifndef TASK_H
#define TASK_H
#include "portable.h"
#include "list.h"
/*-----------------------------------------------------------
* MACROS AND DEFINITIONS
*----------------------------------------------------------*/
#define tskKERNEL_VERSION_NUMBER "V4.2.1"
/**
* task. h
*
* Type by which tasks are referenced. For example, a call to xTaskCreate
* returns (via a pointer parameter) an xTaskHandle variable that can then
* be used as a parameter to vTaskDelete to delete the task.
*
* \page xTaskHandle xTaskHandle
* \ingroup Tasks
*/
typedef void *xTaskHandle;
/*
* Used internally only.
*/
typedef struct xTIME_OUT
{
portBASE_TYPE xOverflowCount;
portTickType xTimeOnEntering;
} xTimeOutType;
/*
* Defines the priority used by the idle task. This must not be modified.
*
* \ingroup TaskUtils
*/
#define tskIDLE_PRIORITY ( ( unsigned portBASE_TYPE ) 0 )
/**
* task. h
*
* Macro for forcing a context switch.
*
* \page taskYIELD taskYIELD
* \ingroup SchedulerControl
*/
#define taskYIELD() portYIELD()
/**
* task. h
*
* Macro to mark the start of a critical code region. Preemptive context
* switches cannot occur when in a critical region.
*
* NOTE: This may alter the stack (depending on the portable implementation)
* so must be used with care!
*
* \page taskENTER_CRITICAL taskENTER_CRITICAL
* \ingroup SchedulerControl
*/
#define taskENTER_CRITICAL() portENTER_CRITICAL()
/**
* task. h
*
* Macro to mark the end of a critical code region. Preemptive context
* switches cannot occur when in a critical region.
*
* NOTE: This may alter the stack (depending on the portable implementation)
* so must be used with care!
*
* \page taskEXIT_CRITICAL taskEXIT_CRITICAL
* \ingroup SchedulerControl
*/
#define taskEXIT_CRITICAL() portEXIT_CRITICAL()
/**
* task. h
*
* Macro to disable all maskable interrupts.
*
* \page taskDISABLE_INTERRUPTS taskDISABLE_INTERRUPTS
* \ingroup SchedulerControl
*/
#define taskDISABLE_INTERRUPTS() portDISABLE_INTERRUPTS()
/**
* task. h
*
* Macro to enable microcontroller interrupts.
*
* \page taskENABLE_INTERRUPTS taskENABLE_INTERRUPTS
* \ingroup SchedulerControl
*/
#define taskENABLE_INTERRUPTS() portENABLE_INTERRUPTS()
/*-----------------------------------------------------------
* TASK CREATION API
*----------------------------------------------------------*/
/**
* task. h
*
portBASE_TYPE xTaskCreate(
pdTASK_CODE pvTaskCode,
const portCHAR * const pcName,
unsigned portSHORT usStackDepth,
void *pvParameters,
unsigned portBASE_TYPE uxPriority,
xTaskHandle *pvCreatedTask
);
*
* Create a new task and add it to the list of tasks that are ready to run.
*
* @param pvTaskCode Pointer to the task entry function. Tasks
* must be implemented to never return (i.e. continuous loop).
*
* @param pcName A descriptive name for the task. This is mainly used to
* facilitate debugging. Max length defined by tskMAX_TASK_NAME_LEN - default
* is 16.
*
* @param usStackDepth The size of the task stack specified as the number of
* variables the stack can hold - not the number of bytes. For example, if
* the stack is 16 bits wide and usStackDepth is defined as 100, 200 bytes
* will be allocated for stack storage.
*
* @param pvParameters Pointer that will be used as the parameter for the task
* being created.
*
* @param uxPriority The priority at which the task should run.
*
* @param pvCreatedTask Used to pass back a handle by which the created task
* can be referenced.
*
* @return pdPASS if the task was successfully created and added to a ready
* list, otherwise an error code defined in the file errors. h
*
* Example usage:
// Task to be created.
void vTaskCode( void * pvParameters )
{
for( ;; )
{
// Task code goes here.
}
}
// Function that creates a task.
void vOtherFunction( void )
{
unsigned char ucParameterToPass;
xTaskHandle xHandle;
// Create the task, storing the handle.
xTaskCreate( vTaskCode, "NAME", STACK_SIZE, &ucParameterToPass, tskIDLE_PRIORITY, &xHandle );
// Use the handle to delete the task.
vTaskDelete( xHandle );
}
* \defgroup xTaskCreate xTaskCreate
* \ingroup Tasks
*/
signed portBASE_TYPE xTaskCreate (pdTASK_CODE pvTaskCode,
const signed portCHAR * const pcName,
unsigned portSHORT usStackDepth,
void *pvParameters,
unsigned portBASE_TYPE uxPriority,
xTaskHandle * pvCreatedTask);
/**
* task. h
* void vTaskDelete( xTaskHandle pxTask );
*
* INCLUDE_vTaskDelete must be defined as 1 for this function to be available.
* See the configuration section for more information.
*
* Remove a task from the RTOS real time kernels management. The task being
* deleted will be removed from all ready, blocked, suspended and event lists.
*
* NOTE: The idle task is responsible for freeing the kernel allocated
* memory from tasks that have been deleted. It is therefore important that
* the idle task is not starved of microcontroller processing time if your
* application makes any calls to vTaskDelete (). Memory allocated by the
* task code is not automatically freed, and should be freed before the task
* is deleted.
*
* See the demo application file death.c for sample code that utilises
* vTaskDelete ().
*
* @param pxTask The handle of the task to be deleted. Passing NULL will
* cause the calling task to be deleted.
*
* Example usage:
void vOtherFunction( void )
{
xTaskHandle xHandle;
// Create the task, storing the handle.
xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
// Use the handle to delete the task.
vTaskDelete( xHandle );
}
* \defgroup vTaskDelete vTaskDelete
* \ingroup Tasks
*/
void vTaskDelete (xTaskHandle pxTask);
/*-----------------------------------------------------------
* TASK CONTROL API
*----------------------------------------------------------*/
/**
* task. h
* void vTaskDelay( portTickType xTicksToDelay );
*
* Delay a task for a given number of ticks. The actual time that the
* task remains blocked depends on the tick rate. The constant
* portTICK_RATE_MS can be used to calculate real time from the tick
* rate - with the resolution of one tick period.
*
* INCLUDE_vTaskDelay must be defined as 1 for this function to be available.
* See the configuration section for more information.
*
* @param xTicksToDelay The amount of time, in tick periods, that
* the calling task should block.
*
* Example usage:
// Wait 10 ticks before performing an action.
// NOTE:
// This is for demonstration only and would be better achieved
// using vTaskDelayUntil ().
void vTaskFunction( void * pvParameters )
{
portTickType xDelay, xNextTime;
// Calc the time at which we want to perform the action
// next.
xNextTime = xTaskGetTickCount () + ( portTickType ) 10;
for( ;; )
{
xDelay = xNextTime - xTaskGetTickCount ();
xNextTime += ( portTickType ) 10;
// Guard against overflow
if( xDelay <= ( portTickType ) 10 )
{
vTaskDelay( xDelay );
}
// Perform action here.
}
}
* \defgroup vTaskDelay vTaskDelay
* \ingroup TaskCtrl
*/
void vTaskDelay (portTickType xTicksToDelay);
/**
* task. h
* void vTaskDelayUntil( portTickType *pxPreviousWakeTime, portTickType xTimeIncrement );
*
* INCLUDE_vTaskDelayUntil must be defined as 1 for this function to be available.
* See the configuration section for more information.
*
* Delay a task until a specified time. This function can be used by cyclical
* tasks to ensure a constant execution frequency.
*
* This function differs from vTaskDelay () in one important aspect: vTaskDelay () will
* cause a task to block for the specified number of ticks from the time vTaskDelay () is
* called. It is therefore difficult to use vTaskDelay () by itself to generate a fixed
* execution frequency as the time between a task starting to execute and that task
* calling vTaskDelay () may not be fixed [the task may take a different path though the
* code between calls, or may get interrupted or preempted a different number of times
* each time it executes].
*
* Whereas vTaskDelay () specifies a wake time relative to the time at which the function
* is called, vTaskDelayUntil () specifies the absolute (exact) time at which it wishes to
* unblock.
*
* The constant portTICK_RATE_MS can be used to calculate real time from the tick
* rate - with the resolution of one tick period.
*
* @param pxPreviousWakeTime Pointer to a variable that holds the time at which the
* task was last unblocked. The variable must be initialised with the current time
* prior to its first use (see the example below). Following this the variable is
* automatically updated within vTaskDelayUntil ().
*
* @param xTimeIncrement The cycle time period. The task will be unblocked at
* time *pxPreviousWakeTime + xTimeIncrement. Calling vTaskDelayUntil with the
* same xTimeIncrement parameter value will cause the task to execute with
* a fixed interface period.
*
* Example usage:
// Perform an action every 10 ticks.
void vTaskFunction( void * pvParameters )
{
portTickType xLastWakeTime;
const portTickType xFrequency = 10;
// Initialise the xLastWakeTime variable with the current time.
xLastWakeTime = xTaskGetTickCount ();
for( ;; )
{
// Wait for the next cycle.
vTaskDelayUntil( &xLastWakeTime, xFrequency );
// Perform action here.
}
}
* \defgroup vTaskDelayUntil vTaskDelayUntil
* \ingroup TaskCtrl
*/
void vTaskDelayUntil (portTickType * pxPreviousWakeTime,
portTickType xTimeIncrement);
/**
* task. h
* unsigned portBASE_TYPE uxTaskPriorityGet( xTaskHandle pxTask );
*
* INCLUDE_xTaskPriorityGet must be defined as 1 for this function to be available.
* See the configuration section for more information.
*
* Obtain the priority of any task.
*
* @param pxTask Handle of the task to be queried. Passing a NULL
* handle results in the priority of the calling task being returned.
*
* @return The priority of pxTask.
*
* Example usage:
void vAFunction( void )
{
xTaskHandle xHandle;
// Create a task, storing the handle.
xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
// ...
// Use the handle to obtain the priority of the created task.
// It was created with tskIDLE_PRIORITY, but may have changed
// it itself.
if( uxTaskPriorityGet( xHandle ) != tskIDLE_PRIORITY )
{
// The task has changed it's priority.
}
// ...
// Is our priority higher than the created task?
if( uxTaskPriorityGet( xHandle ) < uxTaskPriorityGet( NULL ) )
{
// Our priority (obtained using NULL handle) is higher.
}
}
* \defgroup uxTaskPriorityGet uxTaskPriorityGet
* \ingroup TaskCtrl
*/
unsigned portBASE_TYPE uxTaskPriorityGet (xTaskHandle pxTask);
/**
* task. h
* void vTaskPrioritySet( xTaskHandle pxTask, unsigned portBASE_TYPE uxNewPriority );
*
* INCLUDE_vTaskPrioritySet must be defined as 1 for this function to be available.
* See the configuration section for more information.
*
* Set the priority of any task.
*
* A context switch will occur before the function returns if the priority
* being set is higher than the currently executing task.
*
* @param pxTask Handle to the task for which the priority is being set.
* Passing a NULL handle results in the priority of the calling task being set.
*
* @param uxNewPriority The priority to which the task will be set.
*
* Example usage:
void vAFunction( void )
{
xTaskHandle xHandle;
// Create a task, storing the handle.
xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
// ...
// Use the handle to raise the priority of the created task.
vTaskPrioritySet( xHandle, tskIDLE_PRIORITY + 1 );
// ...
// Use a NULL handle to raise our priority to the same value.
vTaskPrioritySet( NULL, tskIDLE_PRIORITY + 1 );
}
* \defgroup vTaskPrioritySet vTaskPrioritySet
* \ingroup TaskCtrl
*/
void vTaskPrioritySet (xTaskHandle pxTask,
unsigned portBASE_TYPE uxNewPriority);
/**
* task. h
* void vTaskSuspend( xTaskHandle pxTaskToSuspend );
*
* INCLUDE_vTaskSuspend must be defined as 1 for this function to be available.
* See the configuration section for more information.
*
* Suspend any task. When suspended a task will never get any microcontroller
* processing time, no matter what its priority.
*
* Calls to vTaskSuspend are not accumulative -
* i.e. calling vTaskSuspend () twice on the same task still only requires one
* call to vTaskResume () to ready the suspended task.
*
* @param pxTaskToSuspend Handle to the task being suspended. Passing a NULL
* handle will cause the calling task to be suspended.
*
* Example usage:
void vAFunction( void )
{
xTaskHandle xHandle;
// Create a task, storing the handle.
xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
// ...
// Use the handle to suspend the created task.
vTaskSuspend( xHandle );
// ...
// The created task will not run during this period, unless
// another task calls vTaskResume( xHandle ).
//...
// Suspend ourselves.
vTaskSuspend( NULL );
// We cannot get here unless another task calls vTaskResume
// with our handle as the parameter.
}
* \defgroup vTaskSuspend vTaskSuspend
* \ingroup TaskCtrl
*/
void vTaskSuspend (xTaskHandle pxTaskToSuspend);
/**
* task. h
* void vTaskResume( xTaskHandle pxTaskToResume );
*
* INCLUDE_vTaskSuspend must be defined as 1 for this function to be available.
* See the configuration section for more information.
*
* Resumes a suspended task.
*
* A task that has been suspended by one of more calls to vTaskSuspend ()
* will be made available for running again by a single call to
* vTaskResume ().
*
* @param pxTaskToResume Handle to the task being readied.
*
* Example usage:
void vAFunction( void )
{
xTaskHandle xHandle;
// Create a task, storing the handle.
xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, &xHandle );
// ...
// Use the handle to suspend the created task.
vTaskSuspend( xHandle );
// ...
// The created task will not run during this period, unless
// another task calls vTaskResume( xHandle ).
//...
// Resume the suspended task ourselves.
vTaskResume( xHandle );
// The created task will once again get microcontroller processing
// time in accordance with it priority within the system.
}
* \defgroup vTaskResume vTaskResume
* \ingroup TaskCtrl
*/
void vTaskResume (xTaskHandle pxTaskToResume);
/**
* task. h
* void xTaskResumeFromISR( xTaskHandle pxTaskToResume );
*
* INCLUDE_xTaskResumeFromISR must be defined as 1 for this function to be
* available. See the configuration section for more information.
*
* An implementation of vTaskResume() that can be called from within an ISR.
*
* A task that has been suspended by one of more calls to vTaskSuspend ()
* will be made available for running again by a single call to
* xTaskResumeFromISR ().
*
* @param pxTaskToResume Handle to the task being readied.
*
* \defgroup vTaskResumeFromISR vTaskResumeFromISR
* \ingroup TaskCtrl
*/
portBASE_TYPE xTaskResumeFromISR (xTaskHandle pxTaskToResume);
/*-----------------------------------------------------------
* SCHEDULER CONTROL
*----------------------------------------------------------*/
/**
* task. h
* void vTaskStartScheduler( void );
*
* Starts the real time kernel tick processing. After calling the kernel
* has control over which tasks are executed and when. This function
* does not return until an executing task calls vTaskEndScheduler ().
*
* At least one task should be created via a call to xTaskCreate ()
* before calling vTaskStartScheduler (). The idle task is created
* automatically when the first application task is created.
*
* See the demo application file main.c for an example of creating
* tasks and starting the kernel.
*
* Example usage:
void vAFunction( void )
{
// Create at least one task before starting the kernel.
xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
// Start the real time kernel with preemption.
vTaskStartScheduler ();
// Will not get here unless a task calls vTaskEndScheduler ()
}
*
* \defgroup vTaskStartScheduler vTaskStartScheduler
* \ingroup SchedulerControl
*/
void vTaskStartScheduler (void);
/**
* task. h
* void vTaskEndScheduler( void );
*
* Stops the real time kernel tick. All created tasks will be automatically
* deleted and multitasking (either preemptive or cooperative) will
* stop. Execution then resumes from the point where vTaskStartScheduler ()
* was called, as if vTaskStartScheduler () had just returned.
*
* See the demo application file main. c in the demo/PC directory for an
* example that uses vTaskEndScheduler ().
*
* vTaskEndScheduler () requires an exit function to be defined within the
* portable layer (see vPortEndScheduler () in port. c for the PC port). This
* performs hardware specific operations such as stopping the kernel tick.
*
* vTaskEndScheduler () will cause all of the resources allocated by the
* kernel to be freed - but will not free resources allocated by application
* tasks.
*
* Example usage:
void vTaskCode( void * pvParameters )
{
for( ;; )
{
// Task code goes here.
// At some point we want to end the real time kernel processing
// so call ...
vTaskEndScheduler ();
}
}
void vAFunction( void )
{
// Create at least one task before starting the kernel.
xTaskCreate( vTaskCode, "NAME", STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
// Start the real time kernel with preemption.
vTaskStartScheduler ();
// Will only get here when the vTaskCode () task has called
// vTaskEndScheduler (). When we get here we are back to single task
// execution.
}
*
* \defgroup vTaskEndScheduler vTaskEndScheduler
* \ingroup SchedulerControl
*/
void vTaskEndScheduler (void);
/**
* task. h
* void vTaskSuspendAll( void );
*
* Suspends all real time kernel activity while keeping interrupts (including the
* kernel tick) enabled.
*
* After calling vTaskSuspendAll () the calling task will continue to execute
* without risk of being swapped out until a call to xTaskResumeAll () has been
* made.
*
* Example usage:
void vTask1( void * pvParameters )
{
for( ;; )
{
// Task code goes here.
// ...
// At some point the task wants to perform a long operation during
// which it does not want to get swapped out. It cannot use
// taskENTER_CRITICAL ()/taskEXIT_CRITICAL () as the length of the
// operation may cause interrupts to be missed - including the
// ticks.
// Prevent the real time kernel swapping out the task.
vTaskSuspendAll ();
// Perform the operation here. There is no need to use critical
// sections as we have all the microcontroller processing time.
// During this time interrupts will still operate and the kernel
// tick count will be maintained.
// ...
// The operation is complete. Restart the kernel.
xTaskResumeAll ();
}
}
* \defgroup vTaskSuspendAll vTaskSuspendAll
* \ingroup SchedulerControl
*/
void vTaskSuspendAll (void);
/**
* task. h
* portCHAR xTaskResumeAll( void );
*
* Resumes real time kernel activity following a call to vTaskSuspendAll ().
* After a call to vTaskSuspendAll () the kernel will take control of which
* task is executing at any time.
*
* @return If resuming the scheduler caused a context switch then pdTRUE is
* returned, otherwise pdFALSE is returned.
*
* Example usage:
void vTask1( void * pvParameters )
{
for( ;; )
{
// Task code goes here.
// ...
// At some point the task wants to perform a long operation during
// which it does not want to get swapped out. It cannot use
// taskENTER_CRITICAL ()/taskEXIT_CRITICAL () as the length of the
// operation may cause interrupts to be missed - including the
// ticks.
// Prevent the real time kernel swapping out the task.
vTaskSuspendAll ();
// Perform the operation here. There is no need to use critical
// sections as we have all the microcontroller processing time.
// During this time interrupts will still operate and the real
// time kernel tick count will be maintained.
// ...
// The operation is complete. Restart the kernel. We want to force
// a context switch - but there is no point if resuming the scheduler
// caused a context switch already.
if( !xTaskResumeAll () )
{
taskYIELD ();
}
}
}
* \defgroup xTaskResumeAll xTaskResumeAll
* \ingroup SchedulerControl
*/
signed portBASE_TYPE xTaskResumeAll (void);
/*-----------------------------------------------------------
* TASK UTILITIES
*----------------------------------------------------------*/
/**
* task. h
* volatile portTickType xTaskGetTickCount( void );
*
* @return The count of ticks since vTaskStartScheduler was called.
*
* \page xTaskGetTickCount xTaskGetTickCount
* \ingroup TaskUtils
*/
portTickType xTaskGetTickCount (void);
/**
* task. h
* unsigned portSHORT uxTaskGetNumberOfTasks( void );
*
* @return The number of tasks that the real time kernel is currently managing.
* This includes all ready, blocked and suspended tasks. A task that
* has been deleted but not yet freed by the idle task will also be
* included in the count.
*
* \page uxTaskGetNumberOfTasks uxTaskGetNumberOfTasks
* \ingroup TaskUtils
*/
unsigned portBASE_TYPE uxTaskGetNumberOfTasks (void);
/**
* task. h
* void vTaskList( portCHAR *pcWriteBuffer );
*
* configUSE_TRACE_FACILITY, INCLUDE_vTaskDelete and INCLUDE_vTaskSuspend
* must all be defined as 1 for this function to be available.
* See the configuration section for more information.
*
* NOTE: This function will disable interrupts for its duration. It is
* not intended for normal application runtime use but as a debug aid.
*
* Lists all the current tasks, along with their current state and stack
* usage high water mark.
*
* Tasks are reported as blocked ('B'), ready ('R'), deleted ('D') or
* suspended ('S').
*
* @param pcWriteBuffer A buffer into which the above mentioned details
* will be written, in ascii form. This buffer is assumed to be large
* enough to contain the generated report. Approximately 40 bytes per
* task should be sufficient.
*
* \page vTaskList vTaskList
* \ingroup TaskUtils
*/
void vTaskList (signed portCHAR * pcWriteBuffer);
/**
* task. h
* void vTaskStartTrace( portCHAR * pcBuffer, unsigned portBASE_TYPE uxBufferSize );
*
* Starts a real time kernel activity trace. The trace logs the identity of
* which task is running when.
*
* The trace file is stored in binary format. A separate DOS utility called
* convtrce.exe is used to convert this into a tab delimited text file which
* can be viewed and plotted in a spread sheet.
*
* @param pcBuffer The buffer into which the trace will be written.
*
* @param ulBufferSize The size of pcBuffer in bytes. The trace will continue
* until either the buffer in full, or ulTaskEndTrace () is called.
*
* \page vTaskStartTrace vTaskStartTrace
* \ingroup TaskUtils
*/
void vTaskStartTrace (signed portCHAR * pcBuffer,
unsigned portLONG ulBufferSize);
/**
* task. h
* unsigned portLONG ulTaskEndTrace( void );
*
* Stops a kernel activity trace. See vTaskStartTrace ().
*
* @return The number of bytes that have been written into the trace buffer.
*
* \page usTaskEndTrace usTaskEndTrace
* \ingroup TaskUtils
*/
unsigned portLONG ulTaskEndTrace (void);
/*-----------------------------------------------------------
* SCHEDULER INTERNALS AVAILABLE FOR PORTING PURPOSES
*----------------------------------------------------------*/
/*
* THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS ONLY
* INTENDED FOR USE WHEN IMPLEMENTING A PORT OF THE SCHEDULER AND IS
* AN INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
*
* Called from the real time kernel tick (either preemptive or cooperative),
* this increments the tick count and checks if any tasks that are blocked
* for a finite period required removing from a blocked list and placing on
* a ready list.
*/
inline void vTaskIncrementTick (void);
/*
* THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS AN
* INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
*
* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED.
*
* Removes the calling task from the ready list and places it both
* on the list of tasks waiting for a particular event, and the
* list of delayed tasks. The task will be removed from both lists
* and replaced on the ready list should either the event occur (and
* there be no higher priority tasks waiting on the same event) or
* the delay period expires.
*
* @param pxEventList The list containing tasks that are blocked waiting
* for the event to occur.
*
* @param xTicksToWait The maximum amount of time that the task should wait
* for the event to occur. This is specified in kernel ticks,the constant
* portTICK_RATE_MS can be used to convert kernel ticks into a real time
* period.
*/
void vTaskPlaceOnEventList (xList * pxEventList, portTickType xTicksToWait);
/*
* THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS AN
* INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
*
* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED.
*
* Removes a task from both the specified event list and the list of blocked
* tasks, and places it on a ready queue.
*
* xTaskRemoveFromEventList () will be called if either an event occurs to
* unblock a task, or the block timeout period expires.
*
* @return pdTRUE if the task being removed has a higher priority than the task
* making the call, otherwise pdFALSE.
*/
signed portBASE_TYPE xTaskRemoveFromEventList (const xList * pxEventList);
/*
* THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS AN
* INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
*
* INCLUDE_vTaskCleanUpResources and INCLUDE_vTaskSuspend must be defined as 1
* for this function to be available.
* See the configuration section for more information.
*
* Empties the ready and delayed queues of task control blocks, freeing the
* memory allocated for the task control block and task stacks as it goes.
*/
void vTaskCleanUpResources (void);
/*
* THIS FUNCTION MUST NOT BE USED FROM APPLICATION CODE. IT IS ONLY
* INTENDED FOR USE WHEN IMPLEMENTING A PORT OF THE SCHEDULER AND IS
* AN INTERFACE WHICH IS FOR THE EXCLUSIVE USE OF THE SCHEDULER.
*
* Sets the pointer to the current TCB to the TCB of the highest priority task
* that is ready to run.
*/
inline void vTaskSwitchContext (void);
/*
* Return the handle of the calling task.
*/
xTaskHandle xTaskGetCurrentTaskHandle (void);
/*
* Capture the current time status for future reference.
*/
void vTaskSetTimeOutState (xTimeOutType * pxTimeOut);
/*
* Compare the time status now with that previously captured to see if the
* timeout has expired.
*/
portBASE_TYPE xTaskCheckForTimeOut (xTimeOutType * pxTimeOut,
portTickType * pxTicksToWait);
/*
* Shortcut used by the queue implementation to prevent unnecessary call to
* taskYIELD();
*/
void vTaskMissedYield (void);
#endif /* TASK_H */