UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
122 of 362
NXP Semiconductors
UM10208
Chapter 9: LPC2800 Interrupt controller
5.2 Interrupt Pending Register (INT_PENDING - 0x8030 0200)
5.3 Vector Registers (INT_VECTOR0:1, 0x8030 0100 - 0x8030 0104)
Table 120. Interrupt Pending Register (INT_PENDING - 0x8030 0200)
Bits
Name
Description
Reset
value
0
This bit will always read as 0.
0
29:1
PENDINGS
Each of these bits is 1 if the interrupt request signal from this bit
number is asserted, or a software interrupt has been requested
for this bit number. (The PENDING bits from the various
INT_REQ registers are gathered together in this register.)
X
31:30
-
These bits will always read as 0.
00
Table 121. Vector Registers (INT_VECTOR0:1, 0x8030 0100 - 0x8030 0104)
Bits
Name
Description
Reset
value
2:0
-
These bits will always read as 0.
000
7:3
INDEX
If the ISR for IRQ (FIQ) reads INT_PRIOMASK0
(INT_PRIOMASK1) near its start, these bits will contain the
bit/register number of the source that caused the interrupt. Zero in
this field indicates that no interrupt with priority above the current
priority threshold is pending. The ISR can then use the 32-bit value
to access the address of the specific interrupt service routine for
this source, from the first word of the table entry, and a value to
program into the corresponding INT_PRIOMASK register from the
second word of the table entry.
If software programs TABLE_ADDR non-zero, the table must start
at a 2048-byte boundary. If software writes zeroes to
TABLE_ADDR, it can use the value from this register as an index
into a table anywhere in memory.
10:8
-
These bits will always read as 0.
000
31:11 TABLE_ADDR At least for INT_VECTOR 0 which applies to IRQ, software can set
these bits to the base address of a table in memory that contains
the addresses of individual service routines in the first word of
each 2-word entry in the table. If the ISR starting at this address
allows nested interrupts, the second word of the entry should
contain a Priority Limit value that controls what priority is allowed to
interrupt, or 0x0F to prevent nested interrupts.
0