NXP Semiconductors LPC5411 Series

LPC5411x All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2018. All rights reserved.
Product data sheet Rev. 2.1 — 9 May 2018 43 of 105
NXP Semiconductors
LPC5411x
32-bit ARM Cortex-M4/M0+ microcontroller
• The Watchdog clock (WDCLK) source is a selectable frequency in the range of 6 kHz
to 1.5 MHz. The accuracy of this clock is limited to +/- 40% over temperature, voltage,
and silicon processing variations.
• The Watchdog timer can be configured to run in deep-sleep mode.
• Debug mode.
7.20.4 RTC timer
The RTC block has two timers: main RTC timer, and high-resolution/wake-up timer. The
main RTC timer is a 32-bit timer that uses a 1 Hz clock and is intended to run continuously
as a real-time clock. When the timer value reaches a match value, an interrupt is raised.
The alarm interrupt can also wake up the part from any low power mode, if enabled.
The high-resolution or wake-up timer is a 16-bit timer that uses a 1 kHz clock and
operates as a one-shot down timer. When the timer is loaded, it starts counting down to 0
at which point an interrupt is raised. The interrupt can be used to wake-up the part from
any low power modes. This timer is intended to be used for timed wake-up from
deep-sleep or deep power-down modes. The high-resolution wake-up timer can be
disabled to conserve power if not used.
The RTC timer uses the 32.768 kHz clock input to create a 1 Hz or 1 kHz clock.
7.20.4.1 Features
• The RTC oscillator has the following clock outputs:
– 32.768 kHz clock, selectable for system clock and CLKOUT pin.
– 1 Hz clock for RTC timing.
– 1 kHz clock for high-resolution RTC timing.
• 32-bit, 1 Hz RTC counter and associated match register for alarm generation.
• Separate 16-bit high-resolution/wake-up timer clocked at 1 kHz for 1 ms resolution
with a more that one minute maximum time-out period.
• RTC alarm and high-resolution/wake-up timer time-out each generate independent
interrupt requests. Either time-out can wake up the part from any of the low power
modes, including deep power-down.
7.20.5 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.
7.20.5.1 Features
• 24-bit interrupt timer.
• Four channels independently counting down from individually set values.
• Repeat interrupt, one-shot interrupt, and one-shot bus stall modes.