
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
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6.1 How to read this chapter
The LPC82x provides an on-chip API in the boot ROM to optimize power consumption in
active and sleep modes. See
Read this chapter to configure the reduced power modes Deep-sleep mode, Power-down
mode, and Deep power-down mode.
Remark:
The external clock input WKTCLKIN on the wake-up timer is not available on the
TSSOP20 package.
6.2 Features
•
Reduced power modes control
•
Low-power oscillator control
•
Five general purpose backup registers to retain data in Deep power-down mode
6.3 Basic configuration
The PMU is always on as long as V
DD
is present.
If using the WAKEUP function, disable the hysteresis for the WAKEUP pad in the
DPDCTRL register when the supply voltage VDD is below 2.2 V. See
.
If using the WKTCLKIN function, disable the hysteresis for that pin in the DPDCTRL
register. See
6.3.1 Low power modes in the ARM Cortex-M0+ core
Entering and exiting the low power modes is always controlled by the ARM Cortex-M0+
core. The SCR register is the software interface for controlling the core’s actions when
entering a low power mode. The SCR register is located on the ARM private peripheral
bus. For details, see
6.3.1.1 System control register
The System control register (SCR) controls entry to and exit from a low power state. This
register is located on the private peripheral bus and is a R/W register with reset value of
0x0000 0000. The SCR register allows to put the ARM core into sleep mode or the entire
system in Deep-sleep or Power-down mode. To set the low power state with
SLEEPDEEP = 1 to either deep-sleep or power-down or to enter the Deep power-down
mode, use the PCON register (
).
UM10800
Chapter 6: LPC82x Reduced power modes and power
management
Rev. 1.2 — 5 October 2016
User manual