UM11029
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User manual
Rev. 1.0 — 16 June 2017
216 of 515
NXP Semiconductors
UM11029
Chapter 13: LPC84x Pin interrupts/pattern match engine
13.5.1 Pin interrupts
From all available GPIO pins, up to eight pins can be selected in the system control block
to serve as external interrupt pins (see
). The external interrupt pins are
connected to eight individual interrupts in the NVIC and are created based on rising or
falling edges or on the input level on the pin.
13.5.2 Pattern match engine
The pattern match feature allows complex boolean expressions to be constructed from
the same set of eight GPIO pins that were selected for the GPIO pin interrupts. Each term
in the boolean expression is implemented as one slice of the pattern match engine. A slice
consists of an input selector and a detect logic. The slice input selector selects one input
from the available eight inputs with each input connected to a pin by the input’s PINTSEL
register.
The detect logic monitors the selected input continuously and creates a HIGH output if the
input qualifies as detected. Several terms can be combined to a minterm by designating a
slice as an endpoint of the expression. A pin interrupt for this slice is asserted when the
minterm evaluates as true.
Fig 15. Pin interrupt connections
n
n
EDGE/LEVEL
DETECT LOGIC
EDGE/LEVEL
DETECT LOGIC
PINTSEL0
PINTSEL7
All GPIO pins
All GPIO pins
SYSCON
NVIC pin interrupt 0
NVIC pin interrupt 7