Datasheet

Section 5 Interrupt Controller
Rev. 3.00 Sep. 28, 2009 Page 117 of 910
REJ09B0350-0300
5.6 Interrupt Control Modes and Interrupt Operation
The interrupt controller has two modes: interrupt control mode 0 and interrupt control mode 1.
Interrupt operations differ depending on the interrupt control mode. NMI and address break
interrupts are always accepted except for in the reset state. The interrupt control mode is selected
by SYSCR. Table 5.7 shows the interrupt control modes.
Table 5.7 Interrupt Control Modes
SYSCR Interrupt
Control
Mode INTM1 INTM0
Priority
Setting
Registers
Interrupt
Mask Bits
Description
0 0 0 ICR I Interrupt mask control is performed by
the I bit. Priority levels can be set with
ICR.
1 0 1 ICR I, UI 3-level interrupt mask control is
performed by the I and UI bits. Priority
levels can be set with ICR.
Figure 5.6 shows a block diagram of the priority determination circuit.
ICR
UII
Default priority
determination
Vector
number
Interrupt
acceptance control
and 3-level mask
control
Interrupt
source
Interrupt control modes
0 and 1
Figure 5.6 Block Diagram of Interrupt Control Operation