
591
Bits 6 to 4—Standby Timer Select 2 to 0 (STS2 to STS0): These bits select the time the MCU
waits for the clock to stabilize when software standby mode is cleared and a transition is made to
high-speed mode or medium-speed mode by means of a specific interrupt or instruction. With
crystal oscillation, refer to table 17-4 and make a selection according to the operating frequency so
that the standby time is at least 8 ms (the oscillation stabilization time). With an external clock,
any selection can be made*.
Note: * In the F-ZTAT version, a 16-state standby time cannot be used with an external clock.
Use 2048 states or more.
Bit 6
Bit 5
Bit 4
STS2
STS1
STS0
Description
0
Standby time = 8192 states
(Initial value)
1
Standby time = 16384 states
1
0
Standby time = 32768 states
1
Standby time = 65536 states
1
0
Standby time = 131072 states
1
Standby time = 262144 states
1
0
Standby time = 2048 states
1
Standby time = 16 states*
Note: * Cannot be used in the F-ZTAT version.
Bit 2 to 0—Reserved: This bit cannot be modified and is always read as 0.
Bit 3—Output Port Enable (OPE): Specifies whether the address bus and bus control signals
(
CS0 to CS7, AS, RD, HWR, and LWR) retain their output state or go to the high-impedance state
in software standby mode.
Bit 3
OPE
Description
0
In software standby mode, address bus and bus control signals are high-impedance
1
In software standby mode, address bus and bus control signals retain their output
state
(Initial value)