Datasheet
LPC82x All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 1 — 1 October 2014 21 of 81
NXP Semiconductors
LPC82x
32-bit ARM Cortex-M0+ microcontroller
8.17 Multi-Rate Timer (MRT)
The Multi-Rate Timer (MRT) provides a repetitive interrupt timer with four channels. Each
channel can be programmed with an independent time interval, and each channel
operates independently from the other channels.
8.17.1 Features
• 31-bit interrupt timer
• Four channels independently counting down from individually set values
• Bus stall, repeat and one-shot interrupt modes
8.18 Windowed WatchDog Timer (WWDT)
The watchdog timer resets the controller if software fails to service the watchdog timer
periodically within a programmable time window.
8.18.1 Features
• Internally resets chip if not periodically reloaded during the programmable time-out
period.
• Optional windowed operation requires reload to occur between a minimum and
maximum time period, both programmable.
• Optional warning interrupt can be generated at a programmable time prior to
watchdog time-out.
• Enabled by software but requires a hardware reset or a watchdog reset/interrupt to be
disabled.
• Incorrect feed sequence causes reset or interrupt if enabled.
• Flag to indicate watchdog reset.
• Programmable 24-bit timer with internal prescaler.
• Selectable time period from (T
cy(WDCLK)
256 4) to (T
cy(WDCLK)
2
24
4) in
multiples of T
cy(WDCLK)
4.
• The WatchDog Clock (WDCLK) is generated by the dedicated watchdog oscillator
(WDOSC).
8.19 Self-Wake-up Timer (WKT)
The self-wake-up timer is a 32-bit, loadable down counter. Writing any non-zero value to
this timer automatically enables the counter and launches a count-down sequence. When
the counter is used as a wake-up timer, this write can occur prior to entering a reduced
power mode.
8.19.1 Features
• 32-bit loadable down counter. Counter starts automatically when a count value is
loaded. Time-out generates an interrupt/wake up request.
• The WKT resides in a separate, always-on power domain.
• The WKT supports three clock sources: an external clock on the WKTCLKIN pin, the
low-power oscillator, and the IRC. The low-power oscillator is located in the always-on
power domain, so it can be used as the clock source in Deep power-down mode.