MPC5553/MPC5554 Microcontroller Reference Manual, Rev. 5
10-12 Freescale Semiconductor
10.3.1.3 INTC Interrupt Acknowledge Register (INTC_IACKR)
The INTC_IACKR provides a value that can be used to load the address of an ISR from a vector table. The
vector table can be composed of addresses of the ISRs specific to their respective interrupt vectors.
Also, in software vector mode, the INTC_IACKR has side effects from reads. The effects are the same
regardless of the size of the read. Reading the INTC_IACKR does not have side effects in hardware vector
mode.
NOTE
In software vector mode, the INTC_IACKR must be read before setting
MSR[EE]. No synchronization instruction is needed after reading the
INTC_IACKR and before setting MSR[EE].
Table 10-4. INTC_CPR Field Descriptions
Bits Name Description
0–27 — Reserved.
28–31 PRI
[0:3]
Priority. PRI is the priority of the currently executing ISR according to the field values
defined in Tabl e 1 0-5 .
Table 10-5. PRI Values
PRI Meaning
1111 Priority 15 (highest priority)
1110 Priority 14
1101 Priority 13
1100 Priority 12
1011 Priority 11
1010 Priority 10
1001 Priority 9
1000 Priority 8
0111 Priority 7
0110 Priority 6
0101 Priority 5
0100 Priority 4
0011 Priority 3
0010 Priority 2
0001 Priority 1
0000 Priority 0 (lowest priority)
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