UM10503
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User manual
Rev. 1.3 — 6 July 2012
847 of 1269
NXP Semiconductors
UM10503
Chapter 29: LPC43xx Timer0/1/2/3
–
Continuous operation with optional interrupt generation on match.
–
Stop timer on match with optional interrupt generation.
–
Reset timer on match with optional interrupt generation.
•
Up to four external outputs corresponding to match registers, with the following
capabilities:
–
Set low on match.
–
Set high on match.
–
Toggle on match.
–
Do nothing on match.
29.4 General description
The Timer/Counter is designed to count cycles of the peripheral clock (PCLK) or an
externally-supplied clock, and can optionally generate interrupts or perform other actions
at specified timer values, based on four match registers. It also includes four capture
inputs to trap the timer value when an input signal transitions, optionally generating an
interrupt.
gives a brief summary of each of the Timer/Counter related functions.
29.4.1 Architecture
The block diagram for TIMER/COUNTER0 and TIMER/COUNTER1 is shown in
.
Table 678. Timer/Counter function description
Pin
Type
Description
CAP0_[3:0]
CAP1_[3:0]
CAP2_[3:0]
CAP3_[3:0]
Input
Capture Signals- A transition on a capture input can be configured to
load one of the Capture Registers with the value in the Timer Counter
and optionally generate an interrupt. Capture functionality can be
selected from a number of pins.
Timer/Counter block can select a capture signal as a clock source
instead of the PCLK derived clock. For more details see
.
MAT0_[3:0]
MAT1_[3:0]
MAT2_[3:0]
MAT3_[3:0]
Output
External Match Output - When a match register (MR3:0) equals the timer
counter (TC) this output can either toggle, go LOW, go HIGH, or do
nothing. The External Match Register (EMR) controls the functionality of
this output. Match Output functionality can be selected on a number of
pins in parallel.