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ManualsBrandsNXP SEMICONDUCTORS ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller LQFP 48 (7x7) 32-Bit 72 MHz I/O number 42
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LPC1311_13_42_43 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.
Product data sheet Rev. 5 — 6 June 2012 23 of 74
NXP Semiconductors
LPC1311/13/42/43
32-bit ARM Cortex-M3 microcontroller
7.14 General purpose external event counter/timers
The LPC1311/13/42/43 includes two 32-bit counter/timers and two 16-bit counter/timers.
The counter/timer is designed to count cycles of the system derived clock. It 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.
7.14.1 Features
• A 32-bit/16-bit counter/timer with a programmable 32-bit/16-bit prescaler.
• Counter or timer operation.
• One capture channel 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 match registers per timer 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.
7.15 System tick timer
The ARM Cortex-M3 includes a system tick timer (SYSTICK) that is intended to generate
a dedicated SYSTICK exception at a fixed time interval, normally set to 10 ms.
7.16 Watchdog timer
Remark: The standard Watchdog timer is available on parts LPC1311/13/42/43.
The purpose of the watchdog is to reset the microcontroller within a selectable time
period. When enabled, the watchdog will generate a system reset if the user program fails
to ‘feed’ (or reload) the watchdog within a predetermined amount of time.
7.16.1 Features
• Internally resets chip if not periodically reloaded.
• Debug mode.
• Enabled by software but requires a hardware reset or a watchdog reset/interrupt to be
disabled.
• Incorrect/incomplete feed sequence causes reset/interrupt if enabled.
• Flag to indicate watchdog reset.
• Programmable 24-bit timer with internal prescaler.