I want to have ISR which is out of freeRTOS scope (not handled by rtos - interrupt whose priority level is greater than configMAX_SYSCALL_INTERRUPT_PRIORITY), I sync it with a task in rtos. Since I do computation (math/filtering) within this ISR on periodic base I need to keep ISR variables over time. My ISR is high frequency rate ISR.
My question is what/how variable should I use (local,static,global)? What is the limitation on variable use for this ISR which is out of rtos?
Under preemptive scheduling do I have either time different stack?