
LPC1766_0.02
© NXP B.V. 2008. All rights reserved.
Objective data sheet
Rev. 00.02 — 12 August 2008
25 of 70
NXP Semiconductors
LPC1766
Fast communication chip
• Two 8-word FIFO data buffers are provided, one for transmit and one for receive.
• Generates interrupt requests when buffer levels cross a programmable boundary.
• Two DMA requests, controlled by programmable buffer levels. These are connected
to the GPDMA block.
• Controls include reset, stop and mute options separately for I2S input and I2S output.
7.21 General purpose 32-bit timers/external event counters
The LPC1766 include four 32-bit timer/counters. The timer/counter is designed to count
cycles of the system derived clock or an externally-supplied clock. It can optionally
generate interrupts, generate timed DMA requests, or perform other actions at specified
timer values, based on four match registers. Each timer/counter also includes two capture
inputs to trap the timer value when an input signal transitions, optionally generating an
interrupt.
7.21.1 Features
• A 32-bit timer/counter with a programmable 32-bit prescaler.
• Counter or timer operation.
• Two 32-bit capture channels per timer, that can take a snapshot of the timer value
when an input signal transitions. A capture event may also generate an interrupt.
• Four 32-bit match registers that allow:
– 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.
• Up to two match registers can be used to generate timed DMA requests.
7.22 Pulse width modulator
The PWM is based on the standard Timer block and inherits all of its features, although
only the PWM function is pinned out on the LPC1766. The Timer is designed to count
cycles of the system derived clock and optionally switch pins, generate interrupts or
perform other actions when specified timer values occur, based on seven match registers.
The PWM function is in addition to these features, and is based on match register events.
The ability to separately control rising and falling edge locations allows the PWM to be
used for more applications. For instance, multi-phase motor control typically requires
three non-overlapping PWM outputs with individual control of all three pulse widths and
positions.