W77E058A Datasheet, PDF (46/87 Pages) Winbond – 8-BIT MICROCONTROLLER

W77E058A
the device into Power Down mode and continues from there. When RGSL(EXIF.1) bit is set to 1, the
CPU will use the internal RC oscillator instead of crystal to exit Power Down mode. The
microcontroller will automatically switch from RC oscillator to crystal after clock is stable. The RC
oscillator runs at approximately 2−4 MHz. Using RC oscillator to exit from Power Down mode saves
the time for waiting crystal start-up. It is useful in the low power system which usually be awakened
from a short operation then returns to Power Down mode.
Table 5. Status of external pins during Idle and Power Down
MODE
PROGRAM
MEMORY
ALE
PSEN
PORT0
Idle
Internal
1
Idle
External
1
Power Down Internal
0
Power Down External
0
1
Data
1
Float
0
Data
0
Float
PORT1
Data
Data
Data
Data
PORT2
Data
Address
Data
Data
PORT3
Data
Data
Data
Data
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