FreeRTOS学习笔记4——Timer

FreeRTOS Software Timer Note

FreeRTOS Software Timer Note
Timer回调函数原型
Timer State
Auto Reload Timer
one-Short Timer
Timer command queue
Timer API
Timer create
Timer Start
Set Timer ID
Get Timer ID
Change Timer Period
Reset Timer
Timer examples
Timer create example
Timer start examples
Timer Set ID and Get ID
Timer Reset examples

TOC

Timer回调函数原型

void ATimerCallback( TimerHandle_t xTimer );

Timer State

Auto Reload Timer

one-Short Timer

Timer command queue

Timer API

Timer create

TimerHandle_t xTimerCreate( const char * const pcTimerName,
                            TickType_t xTimerPeriodInTicks,
                            UBaseType_t uxAutoReload,
                            void * pvTimerID,
                            TimerCallbackFunction_t pxCallbackFunction );

Timer Start

BaseType_t xTimerStart( TimerHandle_t xTimer, TickType_t xTicksToWait );

Set Timer ID

void vTimerSetTimerID( const TimerHandle_t xTimer, void *pvNewID );

Get Timer ID

void *pvTimerGetTimerID( TimerHandle_t xTimer );

Change Timer Period

BaseType_t xTimerChangePeriod( TimerHandle_t xTimer,
                                TickType_t xNewTimerPeriodInTicks,
                                TickType_t xTicksToWait );

Reset Timer

BaseType_t xTimerReset( TimerHandle_t xTimer, TickType_t xTicksToWait );

Timer examples

Timer create example

/* Create the one shot timer, storing the handle to the created timer in xOneShotTimer. */
xOneShotTimer = xTimerCreate(
                /* Text name for the software timer - not used by FreeRTOS. */
                "OneShot",
                /* The software timer's period in ticks. */
                mainONE_SHOT_TIMER_PERIOD,
                /* Setting uxAutoRealod to pdFALSE creates a one-shot software timer. */
                pdFALSE,
                /* This example does not use the timer id. */
                0,
                /* The callback function to be used by the software timer being created. */
                prvOneShotTimerCallback );


                /* Create the auto-reload timer, storing the handle to the created timer in xAutoReloadTimer. */
xAutoReloadTimer = xTimerCreate(
                /* Text name for the software timer - not used by FreeRTOS. */
                "AutoReload",
                /* The software timer's period in ticks. */
                mainAUTO_RELOAD_TIMER_PERIOD,
                /* Setting uxAutoRealod to pdTRUE creates an auto-reload timer. */
                pdTRUE,
                /* This example does not use the timer id. */
                0,
                /* The callback function to be used by the software timer being created. */
                prvAutoReloadTimerCallback );

Timer start examples

/* Start the software timers, using a block time of 0 (no block time). The scheduler has
not been started yet so any block time specified here would be ignored anyway. */
xTimer1Started = xTimerStart( xOneShotTimer, 0 );
xTimer2Started = xTimerStart( xAutoReloadTimer, 0 );

Timer Set ID and Get ID

ulExecutionCount = ( uint32_t ) pvTimerGetTimerID( xTimer );
ulExecutionCount++;
vTimerSetTimerID( xTimer, ( void * ) ulExecutionCount );

// stop timer
xTimerStop( xTimer, 0 );

Timer Reset examples

/* Reset the software timer. If the backlight was previously off, then this call
will start the timer. If the backlight was previously on, then this call will
restart the timer. A real application may read key presses in an interrupt. If
this function was an interrupt service routine then xTimerResetFromISR() must be
used instead of xTimerReset(). */
xTimerReset( xBacklightTimer, xShortDelay );

来自为知笔记(Wiz)