UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
119 of 362
NXP Semiconductors
UM10208
Chapter 9: LPC2800 Interrupt controller
3.1 Peripherals that supply multiple interrupts
The Secure Digital and Multimedia Card Interface (SD/MCI) and the USB 2.0 High Speed
Device interface each generate more than one interrupt signal, which are connected
separately to the Interrupt Controller.
In the case of the SD/MCI, the two interrupts allow software to select which conditions
contribute to each interrupt via mask registers. Each interrupt is asserted when at least
one status flag is set and that interrupt is enabled in the related mask register. The two
interrupts allow use of one as FIQ and one as IRQ to the CPU, or to separate some
events for handling by two different interrupt service routines.
MCI interrupt 1 is connected to interrupt controller input 10, while MCI interrupt 2 is
connected to interrupt controller input 11.
Two interrupt priorities may be selected for the USB function interrupts (not the USB DMA
interrupts) via the USB Interrupt Priority Register (USBIntP). Interrupts configured as low
priority are connected to interrupt controller input 26, and interrupts configured as high
priority are connected to interrupt controller input 27.
In addition, each USB DMA channel provides an interrupt signal to the interrupt controller.
The USB DMA channel 0 interrupt is connected to interrupt controller input 28, and the
USB DMA channel 1 interrupt is connected to interrupt controller input 29.
Fig 18. Block diagram of the interrupt controller
ENABLE
PRIO
TARGET
PENDING flag
and
INT_PENDING
register
LATCH
Software Interrupt
Request
SET_SWINT CLR_SWINT
Interrupt Request 29
:
Interrupt Request 1
Input stage 1
29 Input stages
Prioritization
INT_PRIOMASK0,
INT_PRIOMASK1
registers
Output
Selection
interrupt
target
IRQ
FIQ
INT_VECTOR0,
INT_VECTOR1
registers
Interrupt vector
index computation