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1295 lines
59 KiB
1295 lines
59 KiB
/* |
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* FreeRTOS Kernel V10.2.1 |
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* Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved. |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a copy of |
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* this software and associated documentation files (the "Software"), to deal in |
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* the Software without restriction, including without limitation the rights to |
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of |
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* the Software, and to permit persons to whom the Software is furnished to do so, |
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* subject to the following conditions: |
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* |
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* The above copyright notice and this permission notice shall be included in all |
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* copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS |
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR |
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER |
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
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* |
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* http://www.FreeRTOS.org |
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* http://aws.amazon.com/freertos |
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* |
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* 1 tab == 4 spaces! |
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*/ |
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#ifndef TIMERS_H |
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#define TIMERS_H |
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|
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#ifndef INC_FREERTOS_H |
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#error "include FreeRTOS.h must appear in source files before include timers.h" |
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#endif |
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|
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/*lint -save -e537 This headers are only multiply included if the application code |
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happens to also be including task.h. */ |
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#include "task.h" |
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/*lint -restore */ |
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|
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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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|
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/*----------------------------------------------------------- |
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* MACROS AND DEFINITIONS |
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*----------------------------------------------------------*/ |
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|
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/* IDs for commands that can be sent/received on the timer queue. These are to |
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be used solely through the macros that make up the public software timer API, |
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as defined below. The commands that are sent from interrupts must use the |
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highest numbers as tmrFIRST_FROM_ISR_COMMAND is used to determine if the task |
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or interrupt version of the queue send function should be used. */ |
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#define tmrCOMMAND_EXECUTE_CALLBACK_FROM_ISR ( ( BaseType_t ) -2 ) |
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#define tmrCOMMAND_EXECUTE_CALLBACK ( ( BaseType_t ) -1 ) |
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#define tmrCOMMAND_START_DONT_TRACE ( ( BaseType_t ) 0 ) |
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#define tmrCOMMAND_START ( ( BaseType_t ) 1 ) |
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#define tmrCOMMAND_RESET ( ( BaseType_t ) 2 ) |
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#define tmrCOMMAND_STOP ( ( BaseType_t ) 3 ) |
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#define tmrCOMMAND_CHANGE_PERIOD ( ( BaseType_t ) 4 ) |
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#define tmrCOMMAND_DELETE ( ( BaseType_t ) 5 ) |
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|
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#define tmrFIRST_FROM_ISR_COMMAND ( ( BaseType_t ) 6 ) |
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#define tmrCOMMAND_START_FROM_ISR ( ( BaseType_t ) 6 ) |
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#define tmrCOMMAND_RESET_FROM_ISR ( ( BaseType_t ) 7 ) |
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#define tmrCOMMAND_STOP_FROM_ISR ( ( BaseType_t ) 8 ) |
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#define tmrCOMMAND_CHANGE_PERIOD_FROM_ISR ( ( BaseType_t ) 9 ) |
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|
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/** |
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* Type by which software timers are referenced. For example, a call to |
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* xTimerCreate() returns an TimerHandle_t variable that can then be used to |
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* reference the subject timer in calls to other software timer API functions |
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* (for example, xTimerStart(), xTimerReset(), etc.). |
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*/ |
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struct tmrTimerControl; /* The old naming convention is used to prevent breaking kernel aware debuggers. */ |
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typedef struct tmrTimerControl * TimerHandle_t; |
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|
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/* |
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* Defines the prototype to which timer callback functions must conform. |
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*/ |
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typedef void (*TimerCallbackFunction_t)( TimerHandle_t xTimer ); |
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|
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/* |
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* Defines the prototype to which functions used with the |
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* xTimerPendFunctionCallFromISR() function must conform. |
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*/ |
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typedef void (*PendedFunction_t)( void *, uint32_t ); |
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|
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/** |
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* TimerHandle_t xTimerCreate( const char * const pcTimerName, |
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* TickType_t xTimerPeriodInTicks, |
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* UBaseType_t uxAutoReload, |
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* void * pvTimerID, |
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* TimerCallbackFunction_t pxCallbackFunction ); |
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* |
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* Creates a new software timer instance, and returns a handle by which the |
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* created software timer can be referenced. |
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* |
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* Internally, within the FreeRTOS implementation, software timers use a block |
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* of memory, in which the timer data structure is stored. If a software timer |
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* is created using xTimerCreate() then the required memory is automatically |
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* dynamically allocated inside the xTimerCreate() function. (see |
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* http://www.freertos.org/a00111.html). If a software timer is created using |
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* xTimerCreateStatic() then the application writer must provide the memory that |
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* will get used by the software timer. xTimerCreateStatic() therefore allows a |
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* software timer to be created without using any dynamic memory allocation. |
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* |
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* Timers are created in the dormant state. The xTimerStart(), xTimerReset(), |
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* xTimerStartFromISR(), xTimerResetFromISR(), xTimerChangePeriod() and |
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* xTimerChangePeriodFromISR() API functions can all be used to transition a |
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* timer into the active state. |
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* |
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* @param pcTimerName A text name that is assigned to the timer. This is done |
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* purely to assist debugging. The kernel itself only ever references a timer |
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* by its handle, and never by its name. |
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* |
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* @param xTimerPeriodInTicks The timer period. The time is defined in tick |
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* periods so the constant portTICK_PERIOD_MS can be used to convert a time that |
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* has been specified in milliseconds. For example, if the timer must expire |
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* after 100 ticks, then xTimerPeriodInTicks should be set to 100. |
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* Alternatively, if the timer must expire after 500ms, then xPeriod can be set |
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* to ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than or |
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* equal to 1000. |
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* |
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* @param uxAutoReload If uxAutoReload is set to pdTRUE then the timer will |
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* expire repeatedly with a frequency set by the xTimerPeriodInTicks parameter. |
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* If uxAutoReload is set to pdFALSE then the timer will be a one-shot timer and |
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* enter the dormant state after it expires. |
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* |
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* @param pvTimerID An identifier that is assigned to the timer being created. |
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* Typically this would be used in the timer callback function to identify which |
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* timer expired when the same callback function is assigned to more than one |
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* timer. |
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* |
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* @param pxCallbackFunction The function to call when the timer expires. |
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* Callback functions must have the prototype defined by TimerCallbackFunction_t, |
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* which is "void vCallbackFunction( TimerHandle_t xTimer );". |
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* |
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* @return If the timer is successfully created then a handle to the newly |
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* created timer is returned. If the timer cannot be created (because either |
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* there is insufficient FreeRTOS heap remaining to allocate the timer |
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* structures, or the timer period was set to 0) then NULL is returned. |
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* |
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* Example usage: |
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* @verbatim |
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* #define NUM_TIMERS 5 |
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* |
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* // An array to hold handles to the created timers. |
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* TimerHandle_t xTimers[ NUM_TIMERS ]; |
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* |
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* // An array to hold a count of the number of times each timer expires. |
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* int32_t lExpireCounters[ NUM_TIMERS ] = { 0 }; |
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* |
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* // Define a callback function that will be used by multiple timer instances. |
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* // The callback function does nothing but count the number of times the |
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* // associated timer expires, and stop the timer once the timer has expired |
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* // 10 times. |
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* void vTimerCallback( TimerHandle_t pxTimer ) |
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* { |
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* int32_t lArrayIndex; |
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* const int32_t xMaxExpiryCountBeforeStopping = 10; |
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* |
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* // Optionally do something if the pxTimer parameter is NULL. |
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* configASSERT( pxTimer ); |
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* |
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* // Which timer expired? |
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* lArrayIndex = ( int32_t ) pvTimerGetTimerID( pxTimer ); |
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* |
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* // Increment the number of times that pxTimer has expired. |
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* lExpireCounters[ lArrayIndex ] += 1; |
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* |
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* // If the timer has expired 10 times then stop it from running. |
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* if( lExpireCounters[ lArrayIndex ] == xMaxExpiryCountBeforeStopping ) |
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* { |
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* // Do not use a block time if calling a timer API function from a |
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* // timer callback function, as doing so could cause a deadlock! |
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* xTimerStop( pxTimer, 0 ); |
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* } |
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* } |
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* |
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* void main( void ) |
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* { |
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* int32_t x; |
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* |
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* // Create then start some timers. Starting the timers before the scheduler |
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* // has been started means the timers will start running immediately that |
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* // the scheduler starts. |
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* for( x = 0; x < NUM_TIMERS; x++ ) |
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* { |
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* xTimers[ x ] = xTimerCreate( "Timer", // Just a text name, not used by the kernel. |
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* ( 100 * x ), // The timer period in ticks. |
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* pdTRUE, // The timers will auto-reload themselves when they expire. |
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* ( void * ) x, // Assign each timer a unique id equal to its array index. |
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* vTimerCallback // Each timer calls the same callback when it expires. |
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* ); |
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* |
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* if( xTimers[ x ] == NULL ) |
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* { |
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* // The timer was not created. |
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* } |
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* else |
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* { |
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* // Start the timer. No block time is specified, and even if one was |
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* // it would be ignored because the scheduler has not yet been |
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* // started. |
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* if( xTimerStart( xTimers[ x ], 0 ) != pdPASS ) |
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* { |
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* // The timer could not be set into the Active state. |
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* } |
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* } |
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* } |
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* |
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* // ... |
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* // Create tasks here. |
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* // ... |
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* |
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* // Starting the scheduler will start the timers running as they have already |
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* // been set into the active state. |
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* vTaskStartScheduler(); |
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* |
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* // Should not reach here. |
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* for( ;; ); |
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* } |
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* @endverbatim |
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*/ |
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#if( configSUPPORT_DYNAMIC_ALLOCATION == 1 ) |
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TimerHandle_t xTimerCreate( const char * const pcTimerName, /*lint !e971 Unqualified char types are allowed for strings and single characters only. */ |
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const TickType_t xTimerPeriodInTicks, |
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const UBaseType_t uxAutoReload, |
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void * const pvTimerID, |
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TimerCallbackFunction_t pxCallbackFunction ) PRIVILEGED_FUNCTION; |
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#endif |
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/** |
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* TimerHandle_t xTimerCreateStatic(const char * const pcTimerName, |
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* TickType_t xTimerPeriodInTicks, |
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* UBaseType_t uxAutoReload, |
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* void * pvTimerID, |
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* TimerCallbackFunction_t pxCallbackFunction, |
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* StaticTimer_t *pxTimerBuffer ); |
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* |
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* Creates a new software timer instance, and returns a handle by which the |
|
* created software timer can be referenced. |
|
* |
|
* Internally, within the FreeRTOS implementation, software timers use a block |
|
* of memory, in which the timer data structure is stored. If a software timer |
|
* is created using xTimerCreate() then the required memory is automatically |
|
* dynamically allocated inside the xTimerCreate() function. (see |
|
* http://www.freertos.org/a00111.html). If a software timer is created using |
|
* xTimerCreateStatic() then the application writer must provide the memory that |
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* will get used by the software timer. xTimerCreateStatic() therefore allows a |
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* software timer to be created without using any dynamic memory allocation. |
|
* |
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* Timers are created in the dormant state. The xTimerStart(), xTimerReset(), |
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* xTimerStartFromISR(), xTimerResetFromISR(), xTimerChangePeriod() and |
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* xTimerChangePeriodFromISR() API functions can all be used to transition a |
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* timer into the active state. |
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* |
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* @param pcTimerName A text name that is assigned to the timer. This is done |
|
* purely to assist debugging. The kernel itself only ever references a timer |
|
* by its handle, and never by its name. |
|
* |
|
* @param xTimerPeriodInTicks The timer period. The time is defined in tick |
|
* periods so the constant portTICK_PERIOD_MS can be used to convert a time that |
|
* has been specified in milliseconds. For example, if the timer must expire |
|
* after 100 ticks, then xTimerPeriodInTicks should be set to 100. |
|
* Alternatively, if the timer must expire after 500ms, then xPeriod can be set |
|
* to ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than or |
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* equal to 1000. |
|
* |
|
* @param uxAutoReload If uxAutoReload is set to pdTRUE then the timer will |
|
* expire repeatedly with a frequency set by the xTimerPeriodInTicks parameter. |
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* If uxAutoReload is set to pdFALSE then the timer will be a one-shot timer and |
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* enter the dormant state after it expires. |
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* |
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* @param pvTimerID An identifier that is assigned to the timer being created. |
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* Typically this would be used in the timer callback function to identify which |
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* timer expired when the same callback function is assigned to more than one |
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* timer. |
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* |
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* @param pxCallbackFunction The function to call when the timer expires. |
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* Callback functions must have the prototype defined by TimerCallbackFunction_t, |
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* which is "void vCallbackFunction( TimerHandle_t xTimer );". |
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* |
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* @param pxTimerBuffer Must point to a variable of type StaticTimer_t, which |
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* will be then be used to hold the software timer's data structures, removing |
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* the need for the memory to be allocated dynamically. |
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* |
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* @return If the timer is created then a handle to the created timer is |
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* returned. If pxTimerBuffer was NULL then NULL is returned. |
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* |
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* Example usage: |
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* @verbatim |
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* |
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* // The buffer used to hold the software timer's data structure. |
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* static StaticTimer_t xTimerBuffer; |
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* |
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* // A variable that will be incremented by the software timer's callback |
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* // function. |
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* UBaseType_t uxVariableToIncrement = 0; |
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* |
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* // A software timer callback function that increments a variable passed to |
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* // it when the software timer was created. After the 5th increment the |
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* // callback function stops the software timer. |
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* static void prvTimerCallback( TimerHandle_t xExpiredTimer ) |
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* { |
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* UBaseType_t *puxVariableToIncrement; |
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* BaseType_t xReturned; |
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* |
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* // Obtain the address of the variable to increment from the timer ID. |
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* puxVariableToIncrement = ( UBaseType_t * ) pvTimerGetTimerID( xExpiredTimer ); |
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* |
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* // Increment the variable to show the timer callback has executed. |
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* ( *puxVariableToIncrement )++; |
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* |
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* // If this callback has executed the required number of times, stop the |
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* // timer. |
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* if( *puxVariableToIncrement == 5 ) |
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* { |
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* // This is called from a timer callback so must not block. |
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* xTimerStop( xExpiredTimer, staticDONT_BLOCK ); |
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* } |
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* } |
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* |
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* |
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* void main( void ) |
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* { |
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* // Create the software time. xTimerCreateStatic() has an extra parameter |
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* // than the normal xTimerCreate() API function. The parameter is a pointer |
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* // to the StaticTimer_t structure that will hold the software timer |
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* // structure. If the parameter is passed as NULL then the structure will be |
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* // allocated dynamically, just as if xTimerCreate() had been called. |
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* xTimer = xTimerCreateStatic( "T1", // Text name for the task. Helps debugging only. Not used by FreeRTOS. |
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* xTimerPeriod, // The period of the timer in ticks. |
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* pdTRUE, // This is an auto-reload timer. |
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* ( void * ) &uxVariableToIncrement, // A variable incremented by the software timer's callback function |
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* prvTimerCallback, // The function to execute when the timer expires. |
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* &xTimerBuffer ); // The buffer that will hold the software timer structure. |
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* |
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* // The scheduler has not started yet so a block time is not used. |
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* xReturned = xTimerStart( xTimer, 0 ); |
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* |
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* // ... |
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* // Create tasks here. |
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* // ... |
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* |
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* // Starting the scheduler will start the timers running as they have already |
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* // been set into the active state. |
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* vTaskStartScheduler(); |
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* |
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* // Should not reach here. |
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* for( ;; ); |
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* } |
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* @endverbatim |
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*/ |
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#if( configSUPPORT_STATIC_ALLOCATION == 1 ) |
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TimerHandle_t xTimerCreateStatic( const char * const pcTimerName, /*lint !e971 Unqualified char types are allowed for strings and single characters only. */ |
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const TickType_t xTimerPeriodInTicks, |
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const UBaseType_t uxAutoReload, |
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void * const pvTimerID, |
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TimerCallbackFunction_t pxCallbackFunction, |
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StaticTimer_t *pxTimerBuffer ) PRIVILEGED_FUNCTION; |
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#endif /* configSUPPORT_STATIC_ALLOCATION */ |
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|
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/** |
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* void *pvTimerGetTimerID( TimerHandle_t xTimer ); |
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* |
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* Returns the ID assigned to the timer. |
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* |
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* IDs are assigned to timers using the pvTimerID parameter of the call to |
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* xTimerCreated() that was used to create the timer, and by calling the |
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* vTimerSetTimerID() API function. |
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* |
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* If the same callback function is assigned to multiple timers then the timer |
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* ID can be used as time specific (timer local) storage. |
|
* |
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* @param xTimer The timer being queried. |
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* |
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* @return The ID assigned to the timer being queried. |
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* |
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* Example usage: |
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* |
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* See the xTimerCreate() API function example usage scenario. |
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*/ |
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void *pvTimerGetTimerID( const TimerHandle_t xTimer ) PRIVILEGED_FUNCTION; |
|
|
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/** |
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* void vTimerSetTimerID( TimerHandle_t xTimer, void *pvNewID ); |
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* |
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* Sets the ID assigned to the timer. |
|
* |
|
* IDs are assigned to timers using the pvTimerID parameter of the call to |
|
* xTimerCreated() that was used to create the timer. |
|
* |
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* If the same callback function is assigned to multiple timers then the timer |
|
* ID can be used as time specific (timer local) storage. |
|
* |
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* @param xTimer The timer being updated. |
|
* |
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* @param pvNewID The ID to assign to the timer. |
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* |
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* Example usage: |
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* |
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* See the xTimerCreate() API function example usage scenario. |
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*/ |
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void vTimerSetTimerID( TimerHandle_t xTimer, void *pvNewID ) PRIVILEGED_FUNCTION; |
|
|
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/** |
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* BaseType_t xTimerIsTimerActive( TimerHandle_t xTimer ); |
|
* |
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* Queries a timer to see if it is active or dormant. |
|
* |
|
* A timer will be dormant if: |
|
* 1) It has been created but not started, or |
|
* 2) It is an expired one-shot timer that has not been restarted. |
|
* |
|
* Timers are created in the dormant state. The xTimerStart(), xTimerReset(), |
|
* xTimerStartFromISR(), xTimerResetFromISR(), xTimerChangePeriod() and |
|
* xTimerChangePeriodFromISR() API functions can all be used to transition a timer into the |
|
* active state. |
|
* |
|
* @param xTimer The timer being queried. |
|
* |
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* @return pdFALSE will be returned if the timer is dormant. A value other than |
|
* pdFALSE will be returned if the timer is active. |
|
* |
|
* Example usage: |
|
* @verbatim |
|
* // This function assumes xTimer has already been created. |
|
* void vAFunction( TimerHandle_t xTimer ) |
|
* { |
|
* if( xTimerIsTimerActive( xTimer ) != pdFALSE ) // or more simply and equivalently "if( xTimerIsTimerActive( xTimer ) )" |
|
* { |
|
* // xTimer is active, do something. |
|
* } |
|
* else |
|
* { |
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* // xTimer is not active, do something else. |
|
* } |
|
* } |
|
* @endverbatim |
|
*/ |
|
BaseType_t xTimerIsTimerActive( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION; |
|
|
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/** |
|
* TaskHandle_t xTimerGetTimerDaemonTaskHandle( void ); |
|
* |
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* Simply returns the handle of the timer service/daemon task. It it not valid |
|
* to call xTimerGetTimerDaemonTaskHandle() before the scheduler has been started. |
|
*/ |
|
TaskHandle_t xTimerGetTimerDaemonTaskHandle( void ) PRIVILEGED_FUNCTION; |
|
|
|
/** |
|
* BaseType_t xTimerStart( TimerHandle_t xTimer, TickType_t xTicksToWait ); |
|
* |
|
* Timer functionality is provided by a timer service/daemon task. Many of the |
|
* public FreeRTOS timer API functions send commands to the timer service task |
|
* through a queue called the timer command queue. The timer command queue is |
|
* private to the kernel itself and is not directly accessible to application |
|
* code. The length of the timer command queue is set by the |
|
* configTIMER_QUEUE_LENGTH configuration constant. |
|
* |
|
* xTimerStart() starts a timer that was previously created using the |
|
* xTimerCreate() API function. If the timer had already been started and was |
|
* already in the active state, then xTimerStart() has equivalent functionality |
|
* to the xTimerReset() API function. |
|
* |
|
* Starting a timer ensures the timer is in the active state. If the timer |
|
* is not stopped, deleted, or reset in the mean time, the callback function |
|
* associated with the timer will get called 'n' ticks after xTimerStart() was |
|
* called, where 'n' is the timers defined period. |
|
* |
|
* It is valid to call xTimerStart() before the scheduler has been started, but |
|
* when this is done the timer will not actually start until the scheduler is |
|
* started, and the timers expiry time will be relative to when the scheduler is |
|
* started, not relative to when xTimerStart() was called. |
|
* |
|
* The configUSE_TIMERS configuration constant must be set to 1 for xTimerStart() |
|
* to be available. |
|
* |
|
* @param xTimer The handle of the timer being started/restarted. |
|
* |
|
* @param xTicksToWait Specifies the time, in ticks, that the calling task should |
|
* be held in the Blocked state to wait for the start command to be successfully |
|
* sent to the timer command queue, should the queue already be full when |
|
* xTimerStart() was called. xTicksToWait is ignored if xTimerStart() is called |
|
* before the scheduler is started. |
|
* |
|
* @return pdFAIL will be returned if the start command could not be sent to |
|
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will |
|
* be returned if the command was successfully sent to the timer command queue. |
|
* When the command is actually processed will depend on the priority of the |
|
* timer service/daemon task relative to other tasks in the system, although the |
|
* timers expiry time is relative to when xTimerStart() is actually called. The |
|
* timer service/daemon task priority is set by the configTIMER_TASK_PRIORITY |
|
* configuration constant. |
|
* |
|
* Example usage: |
|
* |
|
* See the xTimerCreate() API function example usage scenario. |
|
* |
|
*/ |
|
#define xTimerStart( xTimer, xTicksToWait ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START, ( xTaskGetTickCount() ), NULL, ( xTicksToWait ) ) |
|
|
|
/** |
|
* BaseType_t xTimerStop( TimerHandle_t xTimer, TickType_t xTicksToWait ); |
|
* |
|
* Timer functionality is provided by a timer service/daemon task. Many of the |
|
* public FreeRTOS timer API functions send commands to the timer service task |
|
* through a queue called the timer command queue. The timer command queue is |
|
* private to the kernel itself and is not directly accessible to application |
|
* code. The length of the timer command queue is set by the |
|
* configTIMER_QUEUE_LENGTH configuration constant. |
|
* |
|
* xTimerStop() stops a timer that was previously started using either of the |
|
* The xTimerStart(), xTimerReset(), xTimerStartFromISR(), xTimerResetFromISR(), |
|
* xTimerChangePeriod() or xTimerChangePeriodFromISR() API functions. |
|
* |
|
* Stopping a timer ensures the timer is not in the active state. |
|
* |
|
* The configUSE_TIMERS configuration constant must be set to 1 for xTimerStop() |
|
* to be available. |
|
* |
|
* @param xTimer The handle of the timer being stopped. |
|
* |
|
* @param xTicksToWait Specifies the time, in ticks, that the calling task should |
|
* be held in the Blocked state to wait for the stop command to be successfully |
|
* sent to the timer command queue, should the queue already be full when |
|
* xTimerStop() was called. xTicksToWait is ignored if xTimerStop() is called |
|
* before the scheduler is started. |
|
* |
|
* @return pdFAIL will be returned if the stop command could not be sent to |
|
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will |
|
* be returned if the command was successfully sent to the timer command queue. |
|
* When the command is actually processed will depend on the priority of the |
|
* timer service/daemon task relative to other tasks in the system. The timer |
|
* service/daemon task priority is set by the configTIMER_TASK_PRIORITY |
|
* configuration constant. |
|
* |
|
* Example usage: |
|
* |
|
* See the xTimerCreate() API function example usage scenario. |
|
* |
|
*/ |
|
#define xTimerStop( xTimer, xTicksToWait ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_STOP, 0U, NULL, ( xTicksToWait ) ) |
|
|
|
/** |
|
* BaseType_t xTimerChangePeriod( TimerHandle_t xTimer, |
|
* TickType_t xNewPeriod, |
|
* TickType_t xTicksToWait ); |
|
* |
|
* Timer functionality is provided by a timer service/daemon task. Many of the |
|
* public FreeRTOS timer API functions send commands to the timer service task |
|
* through a queue called the timer command queue. The timer command queue is |
|
* private to the kernel itself and is not directly accessible to application |
|
* code. The length of the timer command queue is set by the |
|
* configTIMER_QUEUE_LENGTH configuration constant. |
|
* |
|
* xTimerChangePeriod() changes the period of a timer that was previously |
|
* created using the xTimerCreate() API function. |
|
* |
|
* xTimerChangePeriod() can be called to change the period of an active or |
|
* dormant state timer. |
|
* |
|
* The configUSE_TIMERS configuration constant must be set to 1 for |
|
* xTimerChangePeriod() to be available. |
|
* |
|
* @param xTimer The handle of the timer that is having its period changed. |
|
* |
|
* @param xNewPeriod The new period for xTimer. Timer periods are specified in |
|
* tick periods, so the constant portTICK_PERIOD_MS can be used to convert a time |
|
* that has been specified in milliseconds. For example, if the timer must |
|
* expire after 100 ticks, then xNewPeriod should be set to 100. Alternatively, |
|
* if the timer must expire after 500ms, then xNewPeriod can be set to |
|
* ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than |
|
* or equal to 1000. |
|
* |
|
* @param xTicksToWait Specifies the time, in ticks, that the calling task should |
|
* be held in the Blocked state to wait for the change period command to be |
|
* successfully sent to the timer command queue, should the queue already be |
|
* full when xTimerChangePeriod() was called. xTicksToWait is ignored if |
|
* xTimerChangePeriod() is called before the scheduler is started. |
|
* |
|
* @return pdFAIL will be returned if the change period command could not be |
|
* sent to the timer command queue even after xTicksToWait ticks had passed. |
|
* pdPASS will be returned if the command was successfully sent to the timer |
|
* command queue. When the command is actually processed will depend on the |
|
* priority of the timer service/daemon task relative to other tasks in the |
|
* system. The timer service/daemon task priority is set by the |
|
* configTIMER_TASK_PRIORITY configuration constant. |
|
* |
|
* Example usage: |
|
* @verbatim |
|
* // This function assumes xTimer has already been created. If the timer |
|
* // referenced by xTimer is already active when it is called, then the timer |
|
* // is deleted. If the timer referenced by xTimer is not active when it is |
|
* // called, then the period of the timer is set to 500ms and the timer is |
|
* // started. |
|
* void vAFunction( TimerHandle_t xTimer ) |
|
* { |
|
* if( xTimerIsTimerActive( xTimer ) != pdFALSE ) // or more simply and equivalently "if( xTimerIsTimerActive( xTimer ) )" |
|
* { |
|
* // xTimer is already active - delete it. |
|
* xTimerDelete( xTimer ); |
|
* } |
|
* else |
|
* { |
|
* // xTimer is not active, change its period to 500ms. This will also |
|
* // cause the timer to start. Block for a maximum of 100 ticks if the |
|
* // change period command cannot immediately be sent to the timer |
|
* // command queue. |
|
* if( xTimerChangePeriod( xTimer, 500 / portTICK_PERIOD_MS, 100 ) == pdPASS ) |
|
* { |
|
* // The command was successfully sent. |
|
* } |
|
* else |
|
* { |
|
* // The command could not be sent, even after waiting for 100 ticks |
|
* // to pass. Take appropriate action here. |
|
* } |
|
* } |
|
* } |
|
* @endverbatim |
|
*/ |
|
#define xTimerChangePeriod( xTimer, xNewPeriod, xTicksToWait ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_CHANGE_PERIOD, ( xNewPeriod ), NULL, ( xTicksToWait ) ) |
|
|
|
/** |
|
* BaseType_t xTimerDelete( TimerHandle_t xTimer, TickType_t xTicksToWait ); |
|
* |
|
* Timer functionality is provided by a timer service/daemon task. Many of the |
|
* public FreeRTOS timer API functions send commands to the timer service task |
|
* through a queue called the timer command queue. The timer command queue is |
|
* private to the kernel itself and is not directly accessible to application |
|
* code. The length of the timer command queue is set by the |
|
* configTIMER_QUEUE_LENGTH configuration constant. |
|
* |
|
* xTimerDelete() deletes a timer that was previously created using the |
|
* xTimerCreate() API function. |
|
* |
|
* The configUSE_TIMERS configuration constant must be set to 1 for |
|
* xTimerDelete() to be available. |
|
* |
|
* @param xTimer The handle of the timer being deleted. |
|
* |
|
* @param xTicksToWait Specifies the time, in ticks, that the calling task should |
|
* be held in the Blocked state to wait for the delete command to be |
|
* successfully sent to the timer command queue, should the queue already be |
|
* full when xTimerDelete() was called. xTicksToWait is ignored if xTimerDelete() |
|
* is called before the scheduler is started. |
|
* |
|
* @return pdFAIL will be returned if the delete command could not be sent to |
|
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will |
|
* be returned if the command was successfully sent to the timer command queue. |
|
* When the command is actually processed will depend on the priority of the |
|
* timer service/daemon task relative to other tasks in the system. The timer |
|
* service/daemon task priority is set by the configTIMER_TASK_PRIORITY |
|
* configuration constant. |
|
* |
|
* Example usage: |
|
* |
|
* See the xTimerChangePeriod() API function example usage scenario. |
|
*/ |
|
#define xTimerDelete( xTimer, xTicksToWait ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_DELETE, 0U, NULL, ( xTicksToWait ) ) |
|
|
|
/** |
|
* BaseType_t xTimerReset( TimerHandle_t xTimer, TickType_t xTicksToWait ); |
|
* |
|
* Timer functionality is provided by a timer service/daemon task. Many of the |
|
* public FreeRTOS timer API functions send commands to the timer service task |
|
* through a queue called the timer command queue. The timer command queue is |
|
* private to the kernel itself and is not directly accessible to application |
|
* code. The length of the timer command queue is set by the |
|
* configTIMER_QUEUE_LENGTH configuration constant. |
|
* |
|
* xTimerReset() re-starts a timer that was previously created using the |
|
* xTimerCreate() API function. If the timer had already been started and was |
|
* already in the active state, then xTimerReset() will cause the timer to |
|
* re-evaluate its expiry time so that it is relative to when xTimerReset() was |
|
* called. If the timer was in the dormant state then xTimerReset() has |
|
* equivalent functionality to the xTimerStart() API function. |
|
* |
|
* Resetting a timer ensures the timer is in the active state. If the timer |
|
* is not stopped, deleted, or reset in the mean time, the callback function |
|
* associated with the timer will get called 'n' ticks after xTimerReset() was |
|
* called, where 'n' is the timers defined period. |
|
* |
|
* It is valid to call xTimerReset() before the scheduler has been started, but |
|
* when this is done the timer will not actually start until the scheduler is |
|
* started, and the timers expiry time will be relative to when the scheduler is |
|
* started, not relative to when xTimerReset() was called. |
|
* |
|
* The configUSE_TIMERS configuration constant must be set to 1 for xTimerReset() |
|
* to be available. |
|
* |
|
* @param xTimer The handle of the timer being reset/started/restarted. |
|
* |
|
* @param xTicksToWait Specifies the time, in ticks, that the calling task should |
|
* be held in the Blocked state to wait for the reset command to be successfully |
|
* sent to the timer command queue, should the queue already be full when |
|
* xTimerReset() was called. xTicksToWait is ignored if xTimerReset() is called |
|
* before the scheduler is started. |
|
* |
|
* @return pdFAIL will be returned if the reset command could not be sent to |
|
* the timer command queue even after xTicksToWait ticks had passed. pdPASS will |
|
* be returned if the command was successfully sent to the timer command queue. |
|
* When the command is actually processed will depend on the priority of the |
|
* timer service/daemon task relative to other tasks in the system, although the |
|
* timers expiry time is relative to when xTimerStart() is actually called. The |
|
* timer service/daemon task priority is set by the configTIMER_TASK_PRIORITY |
|
* configuration constant. |
|
* |
|
* Example usage: |
|
* @verbatim |
|
* // When a key is pressed, an LCD back-light is switched on. If 5 seconds pass |
|
* // without a key being pressed, then the LCD back-light is switched off. In |
|
* // this case, the timer is a one-shot timer. |
|
* |
|
* TimerHandle_t xBacklightTimer = NULL; |
|
* |
|
* // The callback function assigned to the one-shot timer. In this case the |
|
* // parameter is not used. |
|
* void vBacklightTimerCallback( TimerHandle_t pxTimer ) |
|
* { |
|
* // The timer expired, therefore 5 seconds must have passed since a key |
|
* // was pressed. Switch off the LCD back-light. |
|
* vSetBacklightState( BACKLIGHT_OFF ); |
|
* } |
|
* |
|
* // The key press event handler. |
|
* void vKeyPressEventHandler( char cKey ) |
|
* { |
|
* // Ensure the LCD back-light is on, then reset the timer that is |
|
* // responsible for turning the back-light off after 5 seconds of |
|
* // key inactivity. Wait 10 ticks for the command to be successfully sent |
|
* // if it cannot be sent immediately. |
|
* vSetBacklightState( BACKLIGHT_ON ); |
|
* if( xTimerReset( xBacklightTimer, 100 ) != pdPASS ) |
|
* { |
|
* // The reset command was not executed successfully. Take appropriate |
|
* // action here. |
|
* } |
|
* |
|
* // Perform the rest of the key processing here. |
|
* } |
|
* |
|
* void main( void ) |
|
* { |
|
* int32_t x; |
|
* |
|
* // Create then start the one-shot timer that is responsible for turning |
|
* // the back-light off if no keys are pressed within a 5 second period. |
|
* xBacklightTimer = xTimerCreate( "BacklightTimer", // Just a text name, not used by the kernel. |
|
* ( 5000 / portTICK_PERIOD_MS), // The timer period in ticks. |
|
* pdFALSE, // The timer is a one-shot timer. |
|
* 0, // The id is not used by the callback so can take any value. |
|
* vBacklightTimerCallback // The callback function that switches the LCD back-light off. |
|
* ); |
|
* |
|
* if( xBacklightTimer == NULL ) |
|
* { |
|
* // The timer was not created. |
|
* } |
|
* else |
|
* { |
|
* // Start the timer. No block time is specified, and even if one was |
|
* // it would be ignored because the scheduler has not yet been |
|
* // started. |
|
* if( xTimerStart( xBacklightTimer, 0 ) != pdPASS ) |
|
* { |
|
* // The timer could not be set into the Active state. |
|
* } |
|
* } |
|
* |
|
* // ... |
|
* // Create tasks here. |
|
* // ... |
|
* |
|
* // Starting the scheduler will start the timer running as it has already |
|
* // been set into the active state. |
|
* vTaskStartScheduler(); |
|
* |
|
* // Should not reach here. |
|
* for( ;; ); |
|
* } |
|
* @endverbatim |
|
*/ |
|
#define xTimerReset( xTimer, xTicksToWait ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_RESET, ( xTaskGetTickCount() ), NULL, ( xTicksToWait ) ) |
|
|
|
/** |
|
* BaseType_t xTimerStartFromISR( TimerHandle_t xTimer, |
|
* BaseType_t *pxHigherPriorityTaskWoken ); |
|
* |
|
* A version of xTimerStart() that can be called from an interrupt service |
|
* routine. |
|
* |
|
* @param xTimer The handle of the timer being started/restarted. |
|
* |
|
* @param pxHigherPriorityTaskWoken The timer service/daemon task spends most |
|
* of its time in the Blocked state, waiting for messages to arrive on the timer |
|
* command queue. Calling xTimerStartFromISR() writes a message to the timer |
|
* command queue, so has the potential to transition the timer service/daemon |
|
* task out of the Blocked state. If calling xTimerStartFromISR() causes the |
|
* timer service/daemon task to leave the Blocked state, and the timer service/ |
|
* daemon task has a priority equal to or greater than the currently executing |
|
* task (the task that was interrupted), then *pxHigherPriorityTaskWoken will |
|
* get set to pdTRUE internally within the xTimerStartFromISR() function. If |
|
* xTimerStartFromISR() sets this value to pdTRUE then a context switch should |
|
* be performed before the interrupt exits. |
|
* |
|
* @return pdFAIL will be returned if the start command could not be sent to |
|
* the timer command queue. pdPASS will be returned if the command was |
|
* successfully sent to the timer command queue. When the command is actually |
|
* processed will depend on the priority of the timer service/daemon task |
|
* relative to other tasks in the system, although the timers expiry time is |
|
* relative to when xTimerStartFromISR() is actually called. The timer |
|
* service/daemon task priority is set by the configTIMER_TASK_PRIORITY |
|
* configuration constant. |
|
* |
|
* Example usage: |
|
* @verbatim |
|
* // This scenario assumes xBacklightTimer has already been created. When a |
|
* // key is pressed, an LCD back-light is switched on. If 5 seconds pass |
|
* // without a key being pressed, then the LCD back-light is switched off. In |
|
* // this case, the timer is a one-shot timer, and unlike the example given for |
|
* // the xTimerReset() function, the key press event handler is an interrupt |
|
* // service routine. |
|
* |
|
* // The callback function assigned to the one-shot timer. In this case the |
|
* // parameter is not used. |
|
* void vBacklightTimerCallback( TimerHandle_t pxTimer ) |
|
* { |
|
* // The timer expired, therefore 5 seconds must have passed since a key |
|
* // was pressed. Switch off the LCD back-light. |
|
* vSetBacklightState( BACKLIGHT_OFF ); |
|
* } |
|
* |
|
* // The key press interrupt service routine. |
|
* void vKeyPressEventInterruptHandler( void ) |
|
* { |
|
* BaseType_t xHigherPriorityTaskWoken = pdFALSE; |
|
* |
|
* // Ensure the LCD back-light is on, then restart the timer that is |
|
* // responsible for turning the back-light off after 5 seconds of |
|
* // key inactivity. This is an interrupt service routine so can only |
|
* // call FreeRTOS API functions that end in "FromISR". |
|
* vSetBacklightState( BACKLIGHT_ON ); |
|
* |
|
* // xTimerStartFromISR() or xTimerResetFromISR() could be called here |
|
* // as both cause the timer to re-calculate its expiry time. |
|
* // xHigherPriorityTaskWoken was initialised to pdFALSE when it was |
|
* // declared (in this function). |
|
* if( xTimerStartFromISR( xBacklightTimer, &xHigherPriorityTaskWoken ) != pdPASS ) |
|
* { |
|
* // The start command was not executed successfully. Take appropriate |
|
* // action here. |
|
* } |
|
* |
|
* // Perform the rest of the key processing here. |
|
* |
|
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch |
|
* // should be performed. The syntax required to perform a context switch |
|
* // from inside an ISR varies from port to port, and from compiler to |
|
* // compiler. Inspect the demos for the port you are using to find the |
|
* // actual syntax required. |
|
* if( xHigherPriorityTaskWoken != pdFALSE ) |
|
* { |
|
* // Call the interrupt safe yield function here (actual function |
|
* // depends on the FreeRTOS port being used). |
|
* } |
|
* } |
|
* @endverbatim |
|
*/ |
|
#define xTimerStartFromISR( xTimer, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_START_FROM_ISR, ( xTaskGetTickCountFromISR() ), ( pxHigherPriorityTaskWoken ), 0U ) |
|
|
|
/** |
|
* BaseType_t xTimerStopFromISR( TimerHandle_t xTimer, |
|
* BaseType_t *pxHigherPriorityTaskWoken ); |
|
* |
|
* A version of xTimerStop() that can be called from an interrupt service |
|
* routine. |
|
* |
|
* @param xTimer The handle of the timer being stopped. |
|
* |
|
* @param pxHigherPriorityTaskWoken The timer service/daemon task spends most |
|
* of its time in the Blocked state, waiting for messages to arrive on the timer |
|
* command queue. Calling xTimerStopFromISR() writes a message to the timer |
|
* command queue, so has the potential to transition the timer service/daemon |
|
* task out of the Blocked state. If calling xTimerStopFromISR() causes the |
|
* timer service/daemon task to leave the Blocked state, and the timer service/ |
|
* daemon task has a priority equal to or greater than the currently executing |
|
* task (the task that was interrupted), then *pxHigherPriorityTaskWoken will |
|
* get set to pdTRUE internally within the xTimerStopFromISR() function. If |
|
* xTimerStopFromISR() sets this value to pdTRUE then a context switch should |
|
* be performed before the interrupt exits. |
|
* |
|
* @return pdFAIL will be returned if the stop command could not be sent to |
|
* the timer command queue. pdPASS will be returned if the command was |
|
* successfully sent to the timer command queue. When the command is actually |
|
* processed will depend on the priority of the timer service/daemon task |
|
* relative to other tasks in the system. The timer service/daemon task |
|
* priority is set by the configTIMER_TASK_PRIORITY configuration constant. |
|
* |
|
* Example usage: |
|
* @verbatim |
|
* // This scenario assumes xTimer has already been created and started. When |
|
* // an interrupt occurs, the timer should be simply stopped. |
|
* |
|
* // The interrupt service routine that stops the timer. |
|
* void vAnExampleInterruptServiceRoutine( void ) |
|
* { |
|
* BaseType_t xHigherPriorityTaskWoken = pdFALSE; |
|
* |
|
* // The interrupt has occurred - simply stop the timer. |
|
* // xHigherPriorityTaskWoken was set to pdFALSE where it was defined |
|
* // (within this function). As this is an interrupt service routine, only |
|
* // FreeRTOS API functions that end in "FromISR" can be used. |
|
* if( xTimerStopFromISR( xTimer, &xHigherPriorityTaskWoken ) != pdPASS ) |
|
* { |
|
* // The stop command was not executed successfully. Take appropriate |
|
* // action here. |
|
* } |
|
* |
|
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch |
|
* // should be performed. The syntax required to perform a context switch |
|
* // from inside an ISR varies from port to port, and from compiler to |
|
* // compiler. Inspect the demos for the port you are using to find the |
|
* // actual syntax required. |
|
* if( xHigherPriorityTaskWoken != pdFALSE ) |
|
* { |
|
* // Call the interrupt safe yield function here (actual function |
|
* // depends on the FreeRTOS port being used). |
|
* } |
|
* } |
|
* @endverbatim |
|
*/ |
|
#define xTimerStopFromISR( xTimer, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_STOP_FROM_ISR, 0, ( pxHigherPriorityTaskWoken ), 0U ) |
|
|
|
/** |
|
* BaseType_t xTimerChangePeriodFromISR( TimerHandle_t xTimer, |
|
* TickType_t xNewPeriod, |
|
* BaseType_t *pxHigherPriorityTaskWoken ); |
|
* |
|
* A version of xTimerChangePeriod() that can be called from an interrupt |
|
* service routine. |
|
* |
|
* @param xTimer The handle of the timer that is having its period changed. |
|
* |
|
* @param xNewPeriod The new period for xTimer. Timer periods are specified in |
|
* tick periods, so the constant portTICK_PERIOD_MS can be used to convert a time |
|
* that has been specified in milliseconds. For example, if the timer must |
|
* expire after 100 ticks, then xNewPeriod should be set to 100. Alternatively, |
|
* if the timer must expire after 500ms, then xNewPeriod can be set to |
|
* ( 500 / portTICK_PERIOD_MS ) provided configTICK_RATE_HZ is less than |
|
* or equal to 1000. |
|
* |
|
* @param pxHigherPriorityTaskWoken The timer service/daemon task spends most |
|
* of its time in the Blocked state, waiting for messages to arrive on the timer |
|
* command queue. Calling xTimerChangePeriodFromISR() writes a message to the |
|
* timer command queue, so has the potential to transition the timer service/ |
|
* daemon task out of the Blocked state. If calling xTimerChangePeriodFromISR() |
|
* causes the timer service/daemon task to leave the Blocked state, and the |
|
* timer service/daemon task has a priority equal to or greater than the |
|
* currently executing task (the task that was interrupted), then |
|
* *pxHigherPriorityTaskWoken will get set to pdTRUE internally within the |
|
* xTimerChangePeriodFromISR() function. If xTimerChangePeriodFromISR() sets |
|
* this value to pdTRUE then a context switch should be performed before the |
|
* interrupt exits. |
|
* |
|
* @return pdFAIL will be returned if the command to change the timers period |
|
* could not be sent to the timer command queue. pdPASS will be returned if the |
|
* command was successfully sent to the timer command queue. When the command |
|
* is actually processed will depend on the priority of the timer service/daemon |
|
* task relative to other tasks in the system. The timer service/daemon task |
|
* priority is set by the configTIMER_TASK_PRIORITY configuration constant. |
|
* |
|
* Example usage: |
|
* @verbatim |
|
* // This scenario assumes xTimer has already been created and started. When |
|
* // an interrupt occurs, the period of xTimer should be changed to 500ms. |
|
* |
|
* // The interrupt service routine that changes the period of xTimer. |
|
* void vAnExampleInterruptServiceRoutine( void ) |
|
* { |
|
* BaseType_t xHigherPriorityTaskWoken = pdFALSE; |
|
* |
|
* // The interrupt has occurred - change the period of xTimer to 500ms. |
|
* // xHigherPriorityTaskWoken was set to pdFALSE where it was defined |
|
* // (within this function). As this is an interrupt service routine, only |
|
* // FreeRTOS API functions that end in "FromISR" can be used. |
|
* if( xTimerChangePeriodFromISR( xTimer, &xHigherPriorityTaskWoken ) != pdPASS ) |
|
* { |
|
* // The command to change the timers period was not executed |
|
* // successfully. Take appropriate action here. |
|
* } |
|
* |
|
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch |
|
* // should be performed. The syntax required to perform a context switch |
|
* // from inside an ISR varies from port to port, and from compiler to |
|
* // compiler. Inspect the demos for the port you are using to find the |
|
* // actual syntax required. |
|
* if( xHigherPriorityTaskWoken != pdFALSE ) |
|
* { |
|
* // Call the interrupt safe yield function here (actual function |
|
* // depends on the FreeRTOS port being used). |
|
* } |
|
* } |
|
* @endverbatim |
|
*/ |
|
#define xTimerChangePeriodFromISR( xTimer, xNewPeriod, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_CHANGE_PERIOD_FROM_ISR, ( xNewPeriod ), ( pxHigherPriorityTaskWoken ), 0U ) |
|
|
|
/** |
|
* BaseType_t xTimerResetFromISR( TimerHandle_t xTimer, |
|
* BaseType_t *pxHigherPriorityTaskWoken ); |
|
* |
|
* A version of xTimerReset() that can be called from an interrupt service |
|
* routine. |
|
* |
|
* @param xTimer The handle of the timer that is to be started, reset, or |
|
* restarted. |
|
* |
|
* @param pxHigherPriorityTaskWoken The timer service/daemon task spends most |
|
* of its time in the Blocked state, waiting for messages to arrive on the timer |
|
* command queue. Calling xTimerResetFromISR() writes a message to the timer |
|
* command queue, so has the potential to transition the timer service/daemon |
|
* task out of the Blocked state. If calling xTimerResetFromISR() causes the |
|
* timer service/daemon task to leave the Blocked state, and the timer service/ |
|
* daemon task has a priority equal to or greater than the currently executing |
|
* task (the task that was interrupted), then *pxHigherPriorityTaskWoken will |
|
* get set to pdTRUE internally within the xTimerResetFromISR() function. If |
|
* xTimerResetFromISR() sets this value to pdTRUE then a context switch should |
|
* be performed before the interrupt exits. |
|
* |
|
* @return pdFAIL will be returned if the reset command could not be sent to |
|
* the timer command queue. pdPASS will be returned if the command was |
|
* successfully sent to the timer command queue. When the command is actually |
|
* processed will depend on the priority of the timer service/daemon task |
|
* relative to other tasks in the system, although the timers expiry time is |
|
* relative to when xTimerResetFromISR() is actually called. The timer service/daemon |
|
* task priority is set by the configTIMER_TASK_PRIORITY configuration constant. |
|
* |
|
* Example usage: |
|
* @verbatim |
|
* // This scenario assumes xBacklightTimer has already been created. When a |
|
* // key is pressed, an LCD back-light is switched on. If 5 seconds pass |
|
* // without a key being pressed, then the LCD back-light is switched off. In |
|
* // this case, the timer is a one-shot timer, and unlike the example given for |
|
* // the xTimerReset() function, the key press event handler is an interrupt |
|
* // service routine. |
|
* |
|
* // The callback function assigned to the one-shot timer. In this case the |
|
* // parameter is not used. |
|
* void vBacklightTimerCallback( TimerHandle_t pxTimer ) |
|
* { |
|
* // The timer expired, therefore 5 seconds must have passed since a key |
|
* // was pressed. Switch off the LCD back-light. |
|
* vSetBacklightState( BACKLIGHT_OFF ); |
|
* } |
|
* |
|
* // The key press interrupt service routine. |
|
* void vKeyPressEventInterruptHandler( void ) |
|
* { |
|
* BaseType_t xHigherPriorityTaskWoken = pdFALSE; |
|
* |
|
* // Ensure the LCD back-light is on, then reset the timer that is |
|
* // responsible for turning the back-light off after 5 seconds of |
|
* // key inactivity. This is an interrupt service routine so can only |
|
* // call FreeRTOS API functions that end in "FromISR". |
|
* vSetBacklightState( BACKLIGHT_ON ); |
|
* |
|
* // xTimerStartFromISR() or xTimerResetFromISR() could be called here |
|
* // as both cause the timer to re-calculate its expiry time. |
|
* // xHigherPriorityTaskWoken was initialised to pdFALSE when it was |
|
* // declared (in this function). |
|
* if( xTimerResetFromISR( xBacklightTimer, &xHigherPriorityTaskWoken ) != pdPASS ) |
|
* { |
|
* // The reset command was not executed successfully. Take appropriate |
|
* // action here. |
|
* } |
|
* |
|
* // Perform the rest of the key processing here. |
|
* |
|
* // If xHigherPriorityTaskWoken equals pdTRUE, then a context switch |
|
* // should be performed. The syntax required to perform a context switch |
|
* // from inside an ISR varies from port to port, and from compiler to |
|
* // compiler. Inspect the demos for the port you are using to find the |
|
* // actual syntax required. |
|
* if( xHigherPriorityTaskWoken != pdFALSE ) |
|
* { |
|
* // Call the interrupt safe yield function here (actual function |
|
* // depends on the FreeRTOS port being used). |
|
* } |
|
* } |
|
* @endverbatim |
|
*/ |
|
#define xTimerResetFromISR( xTimer, pxHigherPriorityTaskWoken ) xTimerGenericCommand( ( xTimer ), tmrCOMMAND_RESET_FROM_ISR, ( xTaskGetTickCountFromISR() ), ( pxHigherPriorityTaskWoken ), 0U ) |
|
|
|
|
|
/** |
|
* BaseType_t xTimerPendFunctionCallFromISR( PendedFunction_t xFunctionToPend, |
|
* void *pvParameter1, |
|
* uint32_t ulParameter2, |
|
* BaseType_t *pxHigherPriorityTaskWoken ); |
|
* |
|
* |
|
* Used from application interrupt service routines to defer the execution of a |
|
* function to the RTOS daemon task (the timer service task, hence this function |
|
* is implemented in timers.c and is prefixed with 'Timer'). |
|
* |
|
* Ideally an interrupt service routine (ISR) is kept as short as possible, but |
|
* sometimes an ISR either has a lot of processing to do, or needs to perform |
|
* processing that is not deterministic. In these cases |
|
* xTimerPendFunctionCallFromISR() can be used to defer processing of a function |
|
* to the RTOS daemon task. |
|
* |
|
* A mechanism is provided that allows the interrupt to return directly to the |
|
* task that will subsequently execute the pended callback function. This |
|
* allows the callback function to execute contiguously in time with the |
|
* interrupt - just as if the callback had executed in the interrupt itself. |
|
* |
|
* @param xFunctionToPend The function to execute from the timer service/ |
|
* daemon task. The function must conform to the PendedFunction_t |
|
* prototype. |
|
* |
|
* @param pvParameter1 The value of the callback function's first parameter. |
|
* The parameter has a void * type to allow it to be used to pass any type. |
|
* For example, unsigned longs can be cast to a void *, or the void * can be |
|
* used to point to a structure. |
|
* |
|
* @param ulParameter2 The value of the callback function's second parameter. |
|
* |
|
* @param pxHigherPriorityTaskWoken As mentioned above, calling this function |
|
* will result in a message being sent to the timer daemon task. If the |
|
* priority of the timer daemon task (which is set using |
|
* configTIMER_TASK_PRIORITY in FreeRTOSConfig.h) is higher than the priority of |
|
* the currently running task (the task the interrupt interrupted) then |
|
* *pxHigherPriorityTaskWoken will be set to pdTRUE within |
|
* xTimerPendFunctionCallFromISR(), indicating that a context switch should be |
|
* requested before the interrupt exits. For that reason |
|
* *pxHigherPriorityTaskWoken must be initialised to pdFALSE. See the |
|
* example code below. |
|
* |
|
* @return pdPASS is returned if the message was successfully sent to the |
|
* timer daemon task, otherwise pdFALSE is returned. |
|
* |
|
* Example usage: |
|
* @verbatim |
|
* |
|
* // The callback function that will execute in the context of the daemon task. |
|
* // Note callback functions must all use this same prototype. |
|
* void vProcessInterface( void *pvParameter1, uint32_t ulParameter2 ) |
|
* { |
|
* BaseType_t xInterfaceToService; |
|
* |
|
* // The interface that requires servicing is passed in the second |
|
* // parameter. The first parameter is not used in this case. |
|
* xInterfaceToService = ( BaseType_t ) ulParameter2; |
|
* |
|
* // ...Perform the processing here... |
|
* } |
|
* |
|
* // An ISR that receives data packets from multiple interfaces |
|
* void vAnISR( void ) |
|
* { |
|
* BaseType_t xInterfaceToService, xHigherPriorityTaskWoken; |
|
* |
|
* // Query the hardware to determine which interface needs processing. |
|
* xInterfaceToService = prvCheckInterfaces(); |
|
* |
|
* // The actual processing is to be deferred to a task. Request the |
|
* // vProcessInterface() callback function is executed, passing in the |
|
* // number of the interface that needs processing. The interface to |
|
* // service is passed in the second parameter. The first parameter is |
|
* // not used in this case. |
|
* xHigherPriorityTaskWoken = pdFALSE; |
|
* xTimerPendFunctionCallFromISR( vProcessInterface, NULL, ( uint32_t ) xInterfaceToService, &xHigherPriorityTaskWoken ); |
|
* |
|
* // If xHigherPriorityTaskWoken is now set to pdTRUE then a context |
|
* // switch should be requested. The macro used is port specific and will |
|
* // be either portYIELD_FROM_ISR() or portEND_SWITCHING_ISR() - refer to |
|
* // the documentation page for the port being used. |
|
* portYIELD_FROM_ISR( xHigherPriorityTaskWoken ); |
|
* |
|
* } |
|
* @endverbatim |
|
*/ |
|
BaseType_t xTimerPendFunctionCallFromISR( PendedFunction_t xFunctionToPend, void *pvParameter1, uint32_t ulParameter2, BaseType_t *pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION; |
|
|
|
/** |
|
* BaseType_t xTimerPendFunctionCall( PendedFunction_t xFunctionToPend, |
|
* void *pvParameter1, |
|
* uint32_t ulParameter2, |
|
* TickType_t xTicksToWait ); |
|
* |
|
* |
|
* Used to defer the execution of a function to the RTOS daemon task (the timer |
|
* service task, hence this function is implemented in timers.c and is prefixed |
|
* with 'Timer'). |
|
* |
|
* @param xFunctionToPend The function to execute from the timer service/ |
|
* daemon task. The function must conform to the PendedFunction_t |
|
* prototype. |
|
* |
|
* @param pvParameter1 The value of the callback function's first parameter. |
|
* The parameter has a void * type to allow it to be used to pass any type. |
|
* For example, unsigned longs can be cast to a void *, or the void * can be |
|
* used to point to a structure. |
|
* |
|
* @param ulParameter2 The value of the callback function's second parameter. |
|
* |
|
* @param xTicksToWait Calling this function will result in a message being |
|
* sent to the timer daemon task on a queue. xTicksToWait is the amount of |
|
* time the calling task should remain in the Blocked state (so not using any |
|
* processing time) for space to become available on the timer queue if the |
|
* queue is found to be full. |
|
* |
|
* @return pdPASS is returned if the message was successfully sent to the |
|
* timer daemon task, otherwise pdFALSE is returned. |
|
* |
|
*/ |
|
BaseType_t xTimerPendFunctionCall( PendedFunction_t xFunctionToPend, void *pvParameter1, uint32_t ulParameter2, TickType_t xTicksToWait ) PRIVILEGED_FUNCTION; |
|
|
|
/** |
|
* const char * const pcTimerGetName( TimerHandle_t xTimer ); |
|
* |
|
* Returns the name that was assigned to a timer when the timer was created. |
|
* |
|
* @param xTimer The handle of the timer being queried. |
|
* |
|
* @return The name assigned to the timer specified by the xTimer parameter. |
|
*/ |
|
const char * pcTimerGetName( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION; /*lint !e971 Unqualified char types are allowed for strings and single characters only. */ |
|
|
|
/** |
|
* void vTimerSetReloadMode( TimerHandle_t xTimer, const UBaseType_t uxAutoReload ); |
|
* |
|
* Updates a timer to be either an autoreload timer, in which case the timer |
|
* automatically resets itself each time it expires, or a one shot timer, in |
|
* which case the timer will only expire once unless it is manually restarted. |
|
* |
|
* @param xTimer The handle of the timer being updated. |
|
* |
|
* @param uxAutoReload If uxAutoReload is set to pdTRUE then the timer will |
|
* expire repeatedly with a frequency set by the timer's period (see the |
|
* xTimerPeriodInTicks parameter of the xTimerCreate() API function). If |
|
* uxAutoReload is set to pdFALSE then the timer will be a one-shot timer and |
|
* enter the dormant state after it expires. |
|
*/ |
|
void vTimerSetReloadMode( TimerHandle_t xTimer, const UBaseType_t uxAutoReload ) PRIVILEGED_FUNCTION; |
|
|
|
/** |
|
* TickType_t xTimerGetPeriod( TimerHandle_t xTimer ); |
|
* |
|
* Returns the period of a timer. |
|
* |
|
* @param xTimer The handle of the timer being queried. |
|
* |
|
* @return The period of the timer in ticks. |
|
*/ |
|
TickType_t xTimerGetPeriod( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION; |
|
|
|
/** |
|
* TickType_t xTimerGetExpiryTime( TimerHandle_t xTimer ); |
|
* |
|
* Returns the time in ticks at which the timer will expire. If this is less |
|
* than the current tick count then the expiry time has overflowed from the |
|
* current time. |
|
* |
|
* @param xTimer The handle of the timer being queried. |
|
* |
|
* @return If the timer is running then the time in ticks at which the timer |
|
* will next expire is returned. If the timer is not running then the return |
|
* value is undefined. |
|
*/ |
|
TickType_t xTimerGetExpiryTime( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION; |
|
|
|
/* |
|
* Functions beyond this part are not part of the public API and are intended |
|
* for use by the kernel only. |
|
*/ |
|
BaseType_t xTimerCreateTimerTask( void ) PRIVILEGED_FUNCTION; |
|
BaseType_t xTimerGenericCommand( TimerHandle_t xTimer, const BaseType_t xCommandID, const TickType_t xOptionalValue, BaseType_t * const pxHigherPriorityTaskWoken, const TickType_t xTicksToWait ) PRIVILEGED_FUNCTION; |
|
|
|
#if( configUSE_TRACE_FACILITY == 1 ) |
|
void vTimerSetTimerNumber( TimerHandle_t xTimer, UBaseType_t uxTimerNumber ) PRIVILEGED_FUNCTION; |
|
UBaseType_t uxTimerGetTimerNumber( TimerHandle_t xTimer ) PRIVILEGED_FUNCTION; |
|
#endif |
|
|
|
#ifdef __cplusplus |
|
} |
|
#endif |
|
#endif /* TIMERS_H */ |
|
|
|
|
|
|
|
|