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

W77E058A
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
Idle
Internal
1
Idle
External
1
Power Down Internal
0
Power Down External
0
PSEN
1
1
0
0
PORT0
Data
Float
Data
Float
PORT1
Data
Data
Data
Data
PORT2
Data
Address
Data
Data
PORT3
Data
Data
Data
Data
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