Bits 6 to 4: Standby timer select 2 to 0 (STS2 to STS0)
These bits designate the time the CPU and peripheral modules wait for stable clock operation after
exiting from standby mode or watch mode to active mode due to an interrupt. The designation
should be made according to the operating frequency so that the waiting time is at least equal to the
oscillation settling time.
Bit 6
Bit 5
Bit 4
STS2
STS1
STS0
Description
0
0
0
Wait time = 8,192 states
(initial value)
0
0
1
Wait time = 16,384 states
0
1
0
Wait time = 32,768 states
0
1
1
Wait time = 65,536 states
1
0
0
Wait time = 131,072 states
1
0
1
Wait time = 2 states
(External clock mode)
1
1
0
Wait time = 8 states
1
1
1
Wait time = 16 states
Note: In the case that external clock is input, set up the “Standby timer select” selection to External
clock mode before Mode Transition. Also, do not set up to external clock mode, in the case
that it does not use external clock.
Bit 3: Low speed on flag (LSON)
This bit chooses the system clock (ø) or subclock (ø
SUB
) as the CPU operating clock when watch
mode is cleared. The resulting operation mode depends on the combination of other control bits and
interrupt input.
Bit 3
LSON
Description
0
The CPU operates on the system clock (ø)
(initial value)
1
The CPU operates on the subclock (ø
SUB
)
Bits 2: Reserved bits
Bit 2 is reserved: it is always read as 1 and cannot be modified.
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