User manual

System Interface Unit (SIU)
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 4-25
Figure 4-19. Interrupt Table Handling Example
NOTE
The PowerQUICC II differs from previous MPC8xx implementations in
that when an interrupt request occurs, SIVEC can be read. If there are
multiple interrupt sources, SIVEC latches the highest priority interrupt.
Note that the value of SIVEC cannot change while it is being read.
4.3.1.7 SIU External Interrupt Control Register (SIEXR)
Each defined bit in the SIU external interrupt control register (SIEXR), shown in Figure 4-20, determines
whether the corresponding port C line asserts an interrupt request upon either a high-to-low change or any
change on the pin. External interrupts can come from port C (PC[0-15]).
BASE b Routine1
b Routine2
b Routine3
b Routine4
•
•BASE + n
BASE + 4
BASE + 8
BASE + C
BASE +10
BASE
1st Instruction of Routine1
1st Instruction of Routine2
1st Instruction of Routine3
1st Instruction of Routine4
•
•
BASE + n
BASE + 400
BASE + 800
BASE + C00
BASE +1000
•
•
•
•
•
•
INTR: • • •
Save state
R3 <- @ SIVEC
R4 <-- BASE OF BRANCH TABLE
• • •
lbz
add
mtspr
bctr
RX, R3 (0) # load as byte
RX, RX, R4
CTR, RX
INTR: • • •
Save state
R3 <- @ SIVEC
R4 <-- BASE OF BRANCH TABLE
• • •
lhz
add
mtspr
bctr
RX, R3 (0) # load as half
RX, RX, R4
CTR, RX