Need clarification of errata, "Interrupt service routine (ISR) executed with priority of main process".

[AA1]

Hi,

I need clarification of errata, "Interrupt service routine (ISR) executed with priority of main process".

1. I don't understand in which cases this limitation can occur.
2. I don't understand why the workaround used for STM8S (put a SIM instruction at the beginning of the ISR) can't be used for STM8L family. STM8L152 Errata sheet says: workaround none.

Also need clarification of STM8L errata, "Incorrect code execution when WFE execution is interrupted by ISR or event", case 2.

1. I don't understand in which cases this limitation can occur.
2. The workaround is SIM, WFE, RIM. And says: "It is recommended to avoid any interrupts before WFE mode is entered". But WFE instruction doesn't change interrupt mask. So if before, interrupts are disable, they continue disable while WFE is executed. This means that meanwhile no interrupt is serviced. They are lost if WFE execution takes some time or the execution is delayed.

Reference documents:

STM8S105 Errata sheet

STM8L152 Errata sheet

Thank you.