Ijaz, Erik,

What processor are we refering to?

In my experience POWER DOWN is only exited by a RESET.

Ref: intel 27238302:
"The only exit from Power Down for the 80C51 is a hardware reset."


Ref: ATMEL AT89C micro description:
"The only exit from power down is a hardware reset."

Ref: Philips 80c51 Family Hardware 1:
"The only exit from Power Down is a hardware reset."

Now the variants such as Dallas (and others) implement variant specific low power modes are we speaking of these?

regards,
p