Rev. 1.0, 02/00, page 75 of 1141
Bit 6
Low-Speed on Flag (LSON): Determines the operating mode in combination with other
control bits when making a power-down transition by executing a SLEEP instruction. Also
controls whether a transition is made to high-speed mode or to subactive mode when watch mode
is cleared.
Bit 6
LSON
Description
0
•
When a SLEEP instruction is executed in high-speed mode or medium-speed
mode, transition is made to sleep mode, standby mode, or watch mode
•
When a SLEEP instruction is executed in subactive mode, a transition is made
to watch mode, or directly to high-speed mode
•
After watch mode is cleared, a transition is made to high-speed mode
(Initial value)
1
•
When a SLEEP instruction is executed in high-speed mode a transition is made
to watch mode, subactive mode, sleep mode or standby mode
•
When a SLEEP instruction is executed in subactive mode, a transition is made
to subsleep mode or watch mode
•
After watch mode is cleared, a transition is made to subactive mode
Bit 5
Noise Elimination Sampling Frequency Select (NESEL): Selects the frequency at which
the subclock (
φ
w) generated by the subclock pulse generator is sampled with the clock (
φ
)
generated by the system clock oscillator. When
φ
= 5 MHz or higher, clear this bit to 0.
Bit 5
NESEL
Description
0
Sampling at
φ
divided by 16
1
Sampling at
φ
divided by 4
Bits 4 to 2
Reserved: These bits cannot be modified and are always read as 0.
Bits 1 and 0
Subactive Mode Clock Select 1, 0 (SA1, SA0): These bits select the CPU
operating clock in the subactive mode. These bits cannot be modified in the subactive mode.
Bit 1
Bit 0
SA1
SA0
Description
0
0
Operating clock of CPU is
φ
w/8
(Initial value)
0
1
Operating clock of CPU is
φ
w/4
1
*
Operating clock of CPU is
φ
w/2
Note:
*
Don’t care