System Control Register (Syscr) - Renesas H8S/2100 Series Hardware Manual

3.2.2

System Control Register (SYSCR)

SYSCR monitors a reset source, selects the interrupt control mode and the detection edge for
NMI, enables or disables access to the on-chip peripheral module registers, and enables or disables
the on-chip RAM address space.
Initial
Bit Bit Name Value
7, 6 — All 0
5 INTM1 0
4 INTM0 0
3 XRST 1
2 NMIEG 0
R/W Description
R Reserved
The initial value should not be changed.
R Interrupt Control Select Mode 1 and 0
R/W These bits select the interrupt control mode of the
interrupt controller.
For details on the interrupt control modes, see section
5.6, Interrupt Control Modes and Interrupt Operation.
00: Interrupt control mode 0
01: Interrupt control mode 1
10: Setting prohibited
11: Setting prohibited
R External Reset
Indicates the reset source. A reset is caused by an
external reset input, or when the watchdog timer
overflows.
0: A reset is caused when the watchdog timer overflows
1: A reset is caused by an external reset
R/W NMI Edge Select
Selects the valid edge of the NMI interrupt input.
0: An interrupt is requested at the falling edge of NMI
input
1: An interrupt is requested at the rising edge of NMI
input
Section 3 MCU Operating Modes
Rev. 1.00 Apr. 28, 2008 Page 69 of 994
REJ09B0452-0100