106
Figure 5-4 shows a block diagram of the priority decision circuit.
Interrupt
acceptance
control
8-level
mask control
Default priority
determination
Vector number
Interrupt control mode 2
IPR
Interrupt source
I2 to I0
Interrupt
control
mode 0
I
Figure 5-4 Block Diagram of Interrupt Control Operation
(1) Interrupt Acceptance Control
In interrupt control mode 0, interrupt acceptance is controlled by the I bit in CCR.
Table 5-6 shows the interrupts selected in each interrupt control mode.
Table 5-6
Interrupts Selected in Each Interrupt Control Mode (1)
Interrupt Mask Bits
Interrupt Control Mode
I
Selected Interrupts
0
0
All interrupts
1
NMI interrupts
2
*
All interrupts
Legend
*
: Don't care