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8.5 Priority Check
8.5 Priority Check
IWhen multiple interrupt causes are generated simultaneously, this module selects one
having the highest priority and posts the interrupt level and number of the cause to the
CPU.
NMI is given the highest priority among the interrupt causes handled by this module.
■
Priority Check
The criteria for checking the priority of interrupt causes are as follows:
1. NMI
2. Cause that satisfies the following conditions:
• Causes in an interrupt level other than 31 (interrupt inhibited for level 31)
• Causes in the lowest interrupt level
• Among these causes, one with the smallest interrupt number
Table 8.5-1 summarizes the relationships among interrupt causes, numbers, and levels.
Table 8.5-1 Relationships among Interrupt Causes, Numbers, and Levels (1/2)
Cause of interrupt Interrupt number Interrupt
level
Offset TBR default
address
Decimal Hexadecimal
NMI request 15 0F 15(F
H
) fixed 3C0
H
000FFFC0
H
External interrupt 0 16 10 ICR00 3BC
H
000FFFBC
H
External interrupt 1 17 11 ICR01 3B8
H
000FFFB8
H
External interrupt 2 18 12 ICR02 3B4
H
000FFFB4
H
External interrupt 3 19 13 ICR03 3B0
H
000FFFB0
H
UART 0 reception complete 20 14 ICR04 3AC
H
000FFFAC
H
UART 1 reception complete 21 15 ICR05 3A8
H
000FFFA8
H
UART 2 reception complete 22 16 ICR06 3A4
H
000FFFA4
H
UART 0 transmission
complete
23 17 ICR07 3A0
H
000FFFA0
H
UART 1 transmission
complete
24 18 ICR08 39C
H
000FFF9C
H
UART 2 transmission
complete
25 19 ICR09 398
H
000FFF98
H
DMAC 0 (end, error) 26 1A ICR10 394
H
000FFF94
H
DMAC 1 (end, error) 27 1B ICR11 390
H
000FFF90
H