Dear Darrel,

Thank you for the reply. I am using ASM interrupts on your system for the the high priority and your system already uses the shadow register for HP (retfie fast).

My main routine has deep calls and in the low priority interrupts I am using PBP. I was actually overflowing the stack causing a MCU reset (configured for reset under STACK Over/underflow). I have re-structured my code to handle it already.

I must thank you once again for the great job you have done. It is not only about using PBP in Interrupts it is more manageable than asm.