UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
117 of 362
1.
Features
•
Maps all LPC288x interrupt sources to processor FIQ and IRQ
•
Level sensitive sources (see
•
Programmable priority among sources
•
Nested interrupt capability
•
Software interrupt capability for each source
2.
Description
The processor has two interrupt inputs called Interrupt Request (IRQ) and Fast Interrupt
reQuest (FIQ). The LPC288x interrupt controller takes 29 interrupt request inputs and
programmably assigns them to FIQ and IRQ. The programmable assignment scheme
means that priorities of interrupts among the various peripherals can be dynamically
assigned and adjusted.
Fast Interrupt reQuest (FIQ) requests have the highest priority. If more than one request is
assigned to FIQ, the interrupt controller ORs the requests to produce the FIQ signal to the
processor. The fastest possible FIQ latency is achieved when only one request is
classified as FIQ, because in that case the FIQ service routine can simply start dealing
with the device. If more than one request is assigned to the FIQ class, the FIQ service
routine can read a word from the interrupt controller that identifies which FIQ source(s) is
(are) requesting an interrupt.
3.
Interrupt sources
lists the interrupt sources for each peripheral function, and the bit number(s)
or register number(s) associated with each. Each peripheral device may have one or
more interrupt lines to the Vectored Interrupt Controller. Each line may represent more
than one interrupt source -- to maximize the usefulness of
, it includes the
sources within each functional block. There is no significance or priority associated with
the order that sources are shown in this table, nor with the bit number or register number
for each. By convention for this type of interrupt controller, interrupt request numbers, bit
numbers and register numbers start with 1 rather than 0. (Zero in the INDEX field of an
Interrupt Vector register means that no request with priority above the current priority
threshold is pending.)
UM10208
Chapter 9: Interrupt controller
Rev. 02 — 1 June 2007
User manual
Table 117. LPC288x interrupt sources
Bit #/ Register #
Interrupt source
0
reserved
1
Event Router IRQ0
2
Event Router IRQ1
3
Event Router IRQ2
4
Event Router IRQ3