Hitachi H8/3937 Series Hardware Manual page 481

SYSCR2—System control register 2
Bit 7
—
Initial value 1
Read/Write —
Medium speed on flag
0 Operates in active (high-speed) mode
1 Operates in active (medium-speed) mode
Direct transfer on flag
0 • When a SLEEP instruction is executed in active mode, a transition is
made to standby mode, watch mode, or sleep mode
• When a SLEEP instruction is executed in subactive mode, a transition is
made to watch mode or subsleep mode
1 • When a SLEEP instruction is executed in active (high-speed) mode, a direct
transition is made to active (medium-speed) mode if SSBY = 0, MSON = 1, and
LSON = 0, or to subactive mode if SSBY = 1, TMA3 = 1, and LSON = 1
• When a SLEEP instruction is executed in active (medium-speed) mode, a direct
transition is made to active (high-speed) mode if SSBY = 0, MSON = 0, and
LSON = 0, or to subactive mode if SSBY = 1, TMA3 = 1, and LSON = 1
• When a SLEEP instruction is executed in subactive mode, a direct
transition is made to active (high-speed) mode if SSBY = 1, TMA3 = 1, LSON = 0,
and MSON = 0, or to active (medium-speed) mode if SSBY = 1, TMA3 = 1,
LSON = 0, and MSON = 1
Noise elimination sampling frequency select
0 Sampling rate is ø
1 Sampling rate is ø
6 5
— —
1 1
— —
/16
OSC
/4
OSC
H'F1
4 3
NESEL DTON MSON
1 0
R/W R/W R/W
Subactive mode clock select
0 0 ø /8
W
1 ø /4
W
1 ø /2
*
W
System control
2 1 0
SA1 SA0
0 0 0
R/W R/W
*: Don't care
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