System Control Registers - Renesas H8 Series Hardware Manual

Section 5 Power-Down Modes
11. On the H8/38124 Group, operates only when the on-chip oscillator is selected; otherwise stops and stands by. On
the H8/38024, H8/38024S, and H8/38024R Group, stops and stands by.
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
System control register 1
System control register 2
System Control Register 1 (SYSCR1)
Bit 7
SSBY
Initial value 0
Read/Write 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
•
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
Rev. 7.00 Mar 10, 2005 page 122 of 652
REJ09B0042-0700
Abbreviation
SYSCR1
SYSCR2
6 5
STS2 STS1 STS0
0 0
R/W R/W R/W
R/W Initial Value
R/W H'07
R/W H'F0
4 3 2

LSON
0 0 1

R/W
Address
H'FFF0
H'FFF1
1 0
MA1 MA0
1 1
R/W R/W
(initial value)