xTimerStartFromISR macro

BaseType_t xTimerStartFromISR( TimerHandle_t xTimer, BaseType_t *pxHigherPriorityTaskWoken ); A version of xTimerStart() that can be called from an interrupt service routine. 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