3069RF-ZTAT Datasheet, PDF (108/1003 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER

5.2 Register Descriptions
5.2.1 System Control Register (SYSCR)
SYSCR is an 8-bit readable/writable register that controls software standby mode, selects the
action of the UI bit in CCR, selects the NMI edge, and enables or disables the on-chip RAM.
Only bits 3 and 2 are described here. For the other bits, see section 3.3, System Control Register
(SYSCR).
SYSCR is initialized to H'09 by a reset and in hardware standby mode. It is not initialized in
software standby mode.
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
2
1
0
UE NMIEG SSOE RAME
1
0
0
1
R/W R/W R/W R/W
Standby timer
select 2 to 0
Software standby
RAM enable
Software standby
output port enable
NMI edge select
Selects the NMI input edge
User bit enable
Selects whether to use the UI bit in
CCR as a user bit or interrupt mask bit
Rev. 5.0, 09/04, page 86 of 978