PXS20RM Datasheet, PDF (913/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Interrupt Controller (INTC)
28.4.4 INTC Current Priority Register for Processor 0 (INTC_CPR_PRC0)
INTC_BASE+0x8
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
R
0000000000000000
W
RESET: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
R
000000000000
PRI
W
RESET: 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1
= Unimplemented or Reserved
Figure 28-3. INTC Current Priority Register for Processor 0 (INTC_CPR_PRC0)
The Current Priority Register masks any peripheral or software settable interrupt request at the same or
lower priority of the current value of the PRI field in INTC_CPR_PRC0 from generating an interrupt
request to Processor 0. When INTC_IACKR_PRC0 is read in software vector mode, or the interrupt
acknowledge signal from the processor is asserted in hardware vector mode, the value of PRI is pushed
onto the LIFO, and PRI is updated with the priority of the preempting interrupt request. When
INTC_EOIR_PRC0 is written, the LIFO is popped into the INTC_CPR_PRC0’s PRI field. An exception
case in hardware vector mode to this behavior is described in Section 28.2.1.2, Hardware Vector Mode.
The masking priority can be raised or lowered by writing to the PRI field, supporting the PCP. Refer to
Section 28.6.6, Priority Ceiling Protocol.
NOTE
Depending on an SoC implementation’s pipelining capabilities and bus
architecture, a store to modify the PRI field which closely precedes or
follows an access to a shared resource can result in a non-coherent access to
that resource. Refer to Section 28.6.6.2, Ensuring coherency, for example
code to ensure coherency.
PRI[0:3] — Priority.
PRI is the priority of the currently executing ISR according to the field values defined in Table 28-2.
Table 28-2. PRI Values
PRI
1111
1110
1101
1100
1011
1010
1001
1000
Meaning
Priority 15 - highest priority
Priority 14
Priority 13
Priority 12
Priority 11
Priority 10
Priority 9
Priority 8
Freescale Semiconductor
PXS20 Microcontroller Reference Manual, Rev. 1
28-7