4-24 Intel® PXA255 Processor De veloper ’s Manual

System Integration Unit
4.2.2.4 Interrupt Controller IRQ Pending Register (ICIP) and FIQ Pending Register (ICFP)

The ICIP and the ICFP, shown in Table 4-3 3 and Table 4 -34, contain one bit per interrupt (22 total.)

These bits indicate an interrupt request has been made by a unit. Inside the interrupt service

routine, read the ICIP and ICFP to determine the interrupt source. In general, software then reads

status registers within the interrupting device to determine how to service the interrupt . Bits wit hin

the ICPR (see Section 4.2.2.5) are read only, and represent the logical OR of the status bits in the

ICIP and ICFP for a given interrupt. Once an interrupt has been serviced, the handler writes a one

to the required status bit, clearing the pending interrupt at the source.

Clearing the interrupt status bit at the source, automatically clears the corresponding I CIP or ICFP

flag, provided there are no other interrupt status bits set within th e source unit.

Table 4 -36 describes the available first-level interrupts and their location in the ICPR.

Table 4-33. ICIP Bit Definitions

Physical Address
0x40D0_0000 ICIP System Integration Unit
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
IP31
IP30
IP29
IP28
IP27
IP26
IP25
IP24
IP23
IP22
IP21
IP20
IP19
IP18
IP17
reserved
reserved
IP14
IP13
IP12
IP11
IP10
IP9
IP8
reserved
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ? ? ? ? ? ? ? ?
Bits Name Description
<31:8> IP[x] IRQ Pending x (where x = 8 through 14 and 17 through 31).
0 – IRQ NOT requested by any enabled source.
1 – IRQ requested by an enabled source.
<7:0> — reserved

Table 4-34. ICFP Bit Definitions

Physical Address
0x40D0_000C ICFP System Integration Unit
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
FP31
FP30
FP29
FP28
FP27
FP26
FP25
FP24
FP23
FP22
FP21
FP20
FP19
FP18
FP17
reserved
reserved
FP14
FP13
FP12
FP11
FP10
FP9
FP8
reserved
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ? ? ? ? ? ? ? ?
Bits Name Description
<31:8> FP[x] FIQ Pending x (where x = 8 through 14 and 17 through 31).
0 – FIQ NOT requested by any enabled source.
1 – FIQ requested by an enabled source.
<7:0> — reserved