System Control Register (Syscr) - Hitachi H8/3008 Hardware Manual

MDS0 are read-only bits. The mode pin (MD
MDCR is read.
3.3

System Control Register (SYSCR)

SYSCR is an 8-bit register that controls the operation of the H8/3008.
Bit
SSBY
Initial value
Read/Write R/W
Software standby
Enables transition to software standby mode
Bit 7—Software Standby (SSBY): Enables transition to software standby mode. (For further
information about software standby mode see section 18, Power-Down State.)
When software standby mode is exited by an external interrupt, and a transition is made to normal
operation, this bit remains set to 1. To clear this bit, write 0.
Bit 7
SSBY Description
0 SLEEP instruction causes transition to sleep mode
1 SLEEP instruction causes transition to software standby mode
7 6 5
STS2 STS1
0 0 0
R/W R/W
Standby timer select 2 to 0
These bits select the waiting time at
recovery from software standby mode
to MD ) levels are latched into these bits when
2 0
4 3
STS0 UE
0 1
R/W R/W
NMI edge select
Selects the valid edge
of the NMI input
User bit enable
Selects whether to use the UI bit in CCR
as a user bit or an interrupt mask bit
2 1
NMIEG SSOE RAME
0 0
R/W R/W
RAM enable
Enables or
disables
on-chip RAM
Software standby
output port enable
Selects the output state
of the address bus and
bus control signals in
software standby mode
0
1
R/W
(Initial value)
57