void vSoftwareInterruptHandler( void )
{
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* 'Give' the semaphore multiple times. The first will unblock the handler
task, the following 'gives' are to demonstrate that the semaphore latches
the events to allow the handler task to process them in turn without any
events getting lost. This simulates multiple interrupts being taken by the
processor, even though in this case the events are simulated within a single
interrupt occurrence.*/
xSemaphoreGiveFromISR( xCountingSemaphore, &xHigherPriorityTaskWoken );
xSemaphoreGiveFromISR( xCountingSemaphore, &xHigherPriorityTaskWoken );
xSemaphoreGiveFromISR( xCountingSemaphore, &xHigherPriorityTaskWoken );
/* Clear the software interrupt bit using the interrupt controllers
Clear Pending register. */
mainCLEAR_INTERRUPT();
/* Giving the semaphore may have unblocked a task - if it did and the
unblocked task has a priority equal to or above the currently executing
task then xHigherPriorityTaskWoken will have been set to pdTRUE and
portEND_SWITCHING_ISR() will force a context switch to the newly unblocked
higher priority task.
NOTE: The syntax for forcing a context switch within an ISR varies between
FreeRTOS ports. The portEND_SWITCHING_ISR() macro is provided as part of
the Cortex M3 port layer for this purpose. taskYIELD() must never be called
from an ISR! */
portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
}
void vSoftwareInterruptHandler( void )
{
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
static unsigned long ulReceivedNumber;
/* The strings are declared static const to ensure they are not allocated to the
interrupt service routine stack, and exist even when the interrupt service routine
is not executing. */
static const char *pcStrings[] =
{
"String 0\n",
"String 1\n",
"String 2\n",
"String 3\n"
};
/* Loop until the queue is empty. */
while( xQueueReceiveFromISR( xIntegerQueue, &ulReceivedNumber, &xHigherPriorityTaskWoken ) != errQUEUE_EMPTY )
{
/* Truncate the received value to the last two bits (values 0 to 3 inc.), then
send the string that corresponds to the truncated value to the other
queue. */
ulReceivedNumber &= 0x03;
xQueueSendToBackFromISR( xStringQueue, &pcStrings[ ulReceivedNumber ], &xHigherPriorityTaskWoken );
}
/* Clear the software interrupt bit using the interrupt controllers
Clear Pending register. */
mainCLEAR_INTERRUPT();
/* xHigherPriorityTaskWoken was initialised to pdFALSE. It will have then
been set to pdTRUE only if reading from or writing to a queue caused a task
of equal or greater priority than the currently executing task to leave the
Blocked state. When this is the case a context switch should be performed.
In all other cases a context switch is not necessary.
NOTE: The syntax for forcing a context switch within an ISR varies between
FreeRTOS ports. The portEND_SWITCHING_ISR() macro is provided as part of
the Cortex M3 port layer for this purpose. taskYIELD() must never be called
from an ISR! */
portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
}
void vSoftwareInterruptHandler(void)
{
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* 'Give' the semaphore to unblock the task. */
xSemaphoreGiveFromISR(xBinarySemaphore, &xHigherPriorityTaskWoken);
/* Clear the software interrupt bit using the interrupt controllers
Clear Pending register. */
mainCLEAR_INTERRUPT();
/* Giving the semaphore may have unblocked a task - if it did and the
unblocked task has a priority equal to or above the currently executing
task then xHigherPriorityTaskWoken will have been set to pdTRUE and
portEND_SWITCHING_ISR() will force a context switch to the newly unblocked
higher priority task.
NOTE: The syntax for forcing a context switch within an ISR varies between
FreeRTOS ports. The portEND_SWITCHING_ISR() macro is provided as part of
the Cortex M3 port layer for this purpose. taskYIELD() must never be called
from an ISR! */
portEND_SWITCHING_ISR(xHigherPriorityTaskWoken);
}
