https://devzone.nordicsemi.com/f/nordic-q-a/37099/isr-stack-usage-on-freertosQuite a generic FreeRTOS question probably here but... on an interrupt, what&#39;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&#39;s the use of the stack defined inen-USTelligent Community 13Fri, 03 Aug 2018 11:29:36 GMThttps://devzone.nordicsemi.com/thread/142789?ContentTypeID=1Fri, 03 Aug 2018 11:29:36 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e122dc13-df79-42fc-be9a-df6b4823bda5Susheel Nuguru<p>Since handler mode always use MSP in Cortex-M4,&nbsp;&nbsp;if the new exception interrupted an ISR then it uses the same stack pointed by MSP.</p> <p>if the new exception interrupted a task (thread mode) then it switches from PSP to MSP. Does this answer your question?</p><div style="clear:both;"></div>