UM11029
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© NXP Semiconductors N.V. 2017. All rights reserved.
User manual
Rev. 1.0 — 16 June 2017
253 of 515
NXP Semiconductors
UM11029
Chapter 15: LPC84x Reduced power modes and power management
15.7 Functional description
15.7.1 Power management
The part supports a variety of power control features. In Active mode, when the chip is
running, power and clocks to selected peripherals can be optimized for power
consumption. In addition, there are four special modes of processor power reduction with
different peripherals running: sleep mode, deep-sleep mode, power-down mode, and
deep power-down mode.
Remark:
The Debug mode is not supported in sleep, deep-sleep, power-down, or deep
power-down modes.
15.7.2 Reduced power modes and WWDT lock features
The WWDT lock feature influences the power consumption in any of the power modes
because locking the WWDT clock source forces the watchdog oscillator to be on
independently of the deep-sleep and power-down mode software configuration through
the PDSLEEPCFG register. For details see
Section 22.5.3 “Using the WWDT lock
15.7.3 Active mode
In Active mode, the ARM Cortex-M0+ core, memories, and peripherals are clocked by the
system clock or main clock.
The chip is in Active mode after reset and the default power configuration is determined
by the reset values of the PDRUNCFG and SYSAHBCLKCTRL registers. The power
configuration can be changed during run time.
Table 294. Peripheral configuration in reduced power modes
Peripheral
Sleep mode
Deep-sleep
mode
Power-down
mode
Deep
power-down
mode
FRO
software configurable
on
off
off
FRO output
software configurable
off
off
off
Flash
software configurable
on
off
off
BOD
software configurable
software
configurable
software
configurable
off
PLL
software configurable
off
off
off
SysOsc
software configurable
off
off
off
WDosc/WWDT
software configurable
software
configurable
software
configurable
off
Digital peripherals
software configurable
off
off
off
WKT/low-power
oscillator
software configurable
software
configurable
software
configurable
software
configurable
ADC
software configurable
off
off
off
DAC0/1
software configurable
off
off
off
FAIM
software configurable
off
off
off
Comparator
software configurable
off
off
off