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(4559, 455A) Why do interrupts need to be disabled before execution of the EPOF?

Latest Updated:07/04/2003

Question:

(Power Save)   Why do interrupts need to be disabled before execution of the EPOF instruction?

Answer:

The EPOF instruction and either the POF or POF2 instruction must be executed in succession in order to switch to power down mode. If an interrupt occurs between these two instructions, the MCU will not go into power down mode even after returning from the interrupt routine. For this reason, disable interrupts by executing the DI instruction before executing the EPOF instruction. (#105021)
Suitable Products
4559
455A