Datasheet

Product data sheet Rev. 1.2 — 26 May 2014 40 of 96

NXP Semiconductors

LPC11U6x

32-bit ARM Cortex-M0+ microcontroller

8.25.7.3 Deep-sleep mode

In Deep-sleep mode, the LPC11U6x core is in Sleep mode and all peripheral clocks and

all clock sources are off except for the IRC. The IRC output is disabled unless the IRC is

selected as input to the watchdog timer. In addition, all analog blocks are shut down and

the flash is in standby mode. In Deep-sleep mode, the application can keep the watchdog

oscillator and the BOD circuit running for self-timed wake-up and BOD protection.

The LPC11U6x can wake up from Deep-sleep mode via reset, selected GPIO pins, a

watchdog timer interrupt, an interrupt generating USB port activity, an RTC interrupt, or

any interrupts that the USART1 to USART4 interfaces can create in Deep-sleep mode.

The USART wake-up requires the 32 kHz mode, the synchronous mode, or the CTS

interrupt to be set up.

Deep-sleep mode saves power and allows for short wake-up times.

8.25.7.4 Power-down mode

In Power-down mode, the LPC11U6x is in Sleep mode and all peripheral clocks and all

clock sources are off except for watchdog oscillator if selected. In addition, all analog

blocks and the flash are shut down. In Power-down mode, the application can keep the

BOD circuit running for BOD protection.

The LPC11U6x can wake up from Power-down mode via reset, selected GPIO pins, a

watchdog timer interrupt, an interrupt generating USB port activity, an RTC interrupt, or

any interrupts that the USART1 to USART4 interfaces can create in Power-down mode.

The USART wake-up requires the 32 kHz mode, the synchronous mode, or the CTS

interrupt to be set up.

Power-down mode reduces power consumption compared to Deep-sleep mode at the

expense of longer wake-up times.

8.25.7.5 Deep power-down mode

In Deep power-down mode, power is shut off to the entire chip except for the WAKEUP

pin and the always-on RTC power domain. The LPC11U6x can wake up from Deep

power-down mode via the WAKEUP pin or a wake-up signal generated by the RTC

interrupt.

The LPC11U6x can be blocked from entering Deep power-down mode by setting a lock bit

in the PMU block. Blocking the Deep power-down mode enables the application to keep

the watchdog timer or the BOD running at all times.

If the WAKEUP pin is used in the application, an external pull-up resistor is required on

the WAKEUP pin to hold it HIGH while the part is in deep power-down mode. To wake up

from deep power-down mode, pull the WAKEUP pin LOW. In addition, pull the RESET

HIGH to prevent it from floating while in Deep power-down mode.

8.26 System control

8.26.1 Reset

Reset has four sources on the LPC11U6x: the RESET pin, the WatchDog reset, power-on

reset (POR), and the BrownOut Detection (BOD) circuit. The RESET

pin is a Schmitt

trigger input pin. Assertion of chip reset by any source, once the operating voltage attains

a usable level, starts the IRC and initializes the flash controller.