xTimerPendFunctionCallFromISR() function

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. 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