Datasheet

Section 5 Power-Down Modes
Rev. 6.00 Aug 04, 2006 page 134 of 680
REJ09B0145-0600
5.1.1 System Control Registers
The operation mode is selected using the system control registers described in table 5.3.
Table 5.3 System Control Registers
Name Abbreviation R/W Initial Value Address
System control register 1 SYSCR1 R/W H'07 H'FFF0
System control register 2 SYSCR2 R/W H'F0 H'FFF1
1. System Control Register 1 (SYSCR1)
Bit
Initial value
Read/Write
7
SSBY
0
R/W
6
STS2
0
R/W
5
STS1
0
R/W
4
STS0
0
R/W
3
LSON
0
R/W
0
MA0
1
R/W
2

1

1
MA1
1
R/W
SYSCR1 is an 8-bit read/write register for control of the power-down modes.
Upon reset, SYSCR1 is initialized to H'07.
Bit 7: Software standby (SSBY)
This bit designates transition to standby mode or watch mode.
Bit 7
SSBY Description
0
• When a SLEEP instruction is executed in active mode,
a transition is made to sleep mode
(initial value)
• When a SLEEP instruction is executed in subactive mode, a transition is made
to subsleep mode
1
• When a SLEEP instruction is executed in active mode, a transition is made to
standby mode or watch mode
• When a SLEEP instruction is executed in subactive mode, a transition is made
to watch mode