I’ve upgraded my Atmel UC3A0512 project to FreeRtos V5.0.2. My question regards interrupt handling when the ISR might awaken a different thread due to the ISR placing a message into a queue. The serial ISR example, which does exactly that, looks like this. The 2nd function, TerminalIsr() is the one that’s actually called when an IRQ occurs:
static portBASE_TYPE TerminalIsrHandler( void )
unsigned long Status;
unsigned long IrqSource;
portBASE_TYPE HigherPriorityTaskWoken = pdFALSE;
Code That Does Stuff Goes Here…
/* The return value will be used by portEXIT_SWITCHING_ISR() to know if it
should perform a taskYIELD_FROM_ISR(). Note that the macro explicitly
checks for a 1 in order to do the yield operation. */
return (HigherPriorityTaskWoken ? 1 : 0);
// Terminal interrupt service routine.
// Since we might switch tasks inside here, we have to give it the ‘naked’
// attribute rather than ‘interrupt’ and handle the stack via
// portENTER_SWITCHING_ISR & portEXIT_SWITCHING_ISR.
// In addition, because FreeRTOS is not supposed to run with nested
// interrupts, put all OS calls in a critical section.
static void TerminalIsr( void )
/* This ISR can cause a context switch, so the first statement must be a
call to the portENTER_SWITCHING_ISR() macro. This must be BEFORE any
variable declarations. */
// Now go do the work
/* Exit the ISR. If a task was woken by either a character being received
or transmitted then a context switch will occur. */
My question is - Can I write a single function that handles ISRs rather than incurring the overhead of a 2nd function call? If so, what would the template be for that function?