ISR stack usage on FreeRTOS

[genis]

Quite a generic FreeRTOS question probably here but... on an interrupt, what's the stack the ISR uses? Is it the one from the stack that got interrupted? If so, I guess that also works for the Idle task.

Then, what's the use of the stack defined in the startup fie? Is that only use at bootup until FreeRTOS runs?

[Susheel Nuguru]

Since handler mode always use MSP in Cortex-M4,  if the new exception interrupted an ISR then it uses the same stack pointed by MSP.

if the new exception interrupted a task (thread mode) then it switches from PSP to MSP. Does this answer your question?