Hitachi H8/3690 User Manual
Rev. 1.0, 07/01, page 72 of 372
6.1.2
System Control Register 2(SYSCR2)
The SYSCR2 register controls the power-down modes, as well as SYSCR1.
Bit
Bit Name
Initial Value
R/W
Description
7
6
5
SMSEL
LSON
DTON
0
0
0
R/W
R/W
R/W
Sleep Mode Selection
Low Speed on Flag
Direct Transfer on Flag
These bits select the mode to enter after the execution of
a SLEEP instruction, as well as bit SSBY of SYSCR1.
a SLEEP instruction, as well as bit SSBY of SYSCR1.
For details, see table 6-2.
4
3
2
MA2
MA1
MA0
0
0
0
R/W
R/W
R/W
Active Mode Clock Select 2 to 0
These bits select the operating clock frequency in the
active and sleep modes. The operating clock frequency
changes to the set frequency after the SLEEP instruction
is executed.
active and sleep modes. The operating clock frequency
changes to the set frequency after the SLEEP instruction
is executed.
0XX:
φ
OSC
100:
φ
OSC
/8
101:
φ
OSC
/16
110:
φ
OSC
/32
111:
φ
OSC
/64
1
0
SA1
SA0
0
0
R/W
R/W
Subactive Mode Clock Select 1 and 0
These bits select the operating clock frequency in the
subactive and subsleep modes. The operating clock
frequency changes to the set frequency after the SLEEP
instruction is executed.
subactive and subsleep modes. The operating clock
frequency changes to the set frequency after the SLEEP
instruction is executed.
00:
φ
W
/8
01:
φ
W
/4
1X:
φ
W
/2
Legend X: Don't care.
6.1.3
Module Standby Control Register 1(MSTCR1)
MSTCR1 allows the on-chip peripheral modules to enter a standby state in module units.