xTimerChangePeriod macro

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. 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