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UM10375
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User manual
Rev. 3 — 14 June 2011
281 of 368
NXP Semiconductors
UM10375
Chapter 16: LPC13xx 32-bit timer/counters (CT32B0/1)
16.5 Description
Each Counter/timer 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. Each counter/timer also includes
one capture input to trap the timer value when an input signal transitions, optionally
generating an interrupt.
In PWM mode, three match registers can be used to provide a single-edge controlled
PWM output on the match output pins. One match register is used to control the PWM
cycle length.
Remark:
32-bit counter/timer0 (CT32B0) and 32-bit counter/timer1 (CT32B1) are
functionally identical except for the peripheral base address.
16.6 Pin description
gives a brief summary of each of the counter/timer related pins.
16.7 Clocking and power control
The peripheral clocks (PCLK) to the 32-bit timers are provided by the system clock (see
). These clocks can be disabled through bits 9 and 10 in the SYSAHBCLKCTRL
register (
) for power savings.
16.8 Register description
32-bit counter/timer0 contains the registers shown in
and 32-bit counter/timer1
contains the registers shown in
. More detailed descriptions follow.
Table 268. Counter/timer pin description
Pin
Type
Description
CT32B0_CAP0
CT32B1_CAP0
Input
Capture Signals:
A transition on a capture pin can be configured to load one of the Capture Registers
with the value in the Timer Counter and optionally generate an interrupt.
The counter/timer block can select a capture signal as a clock source instead of the
PCLK derived clock. For more details see
Section 16.8.11 “Count Control Register
(TMR32B0CTCR and TMR32B1TCR)” on page 289
CT32B0_MAT[3:0]
CT32B1_MAT[3:0]
Output
External Match Output of CT32B0/1:
When a match register TMR32B0/1MR3:0 equals the timer counter (TC), this output
can either toggle, go LOW, go HIGH, or do nothing. The External Match Register
(EMR) and the PWM Control register (PWMCON) control the functionality of this
output.