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(4508, 4509) Power Save: Return conditions for key-on wakeup, edge or level?

Latest Updated:01/16/2006

Question:

(Power Save)   What are the return conditions for key-on wakeup, edge or level? [2006/01/16]

Answer:

Ports P00-03, P20, P21, D2 and D3 are returned by level. The return conditions of ports P10-13 and the INT pin can be selected as level or edge. Refer to the datasheet for more details concerning the return conditions.

  • When the return conditions are level
    Using low level input as an example, if the key-on wakeup enable pins are low input when the MCU switches to RAM back-up mode, the MCU will return immediately.
  • When the return conditions are edge
    Using falling edge as an example, if the key-on wakeup enable pins are low input when the MCU switches to RAM back-up mode, the MCU will return when the pins switch back to low input after once switching to high input. Set all key-on wakeup enable pins other than the pins to which the active edge is input to the state opposite to the selected return condition. That is, when the falling edge is selected, set to high, and when the rising edge is selected, set to low.

(#105587)

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