
UM10800
All information provided in this document is subject to legal disclaimers.
© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
69 of 487
NXP Semiconductors
UM10800
Chapter 6: LPC82x Reduced power modes and power management
Remark:
The Debug mode is not supported in Sleep, Deep-sleep, Power-down, or Deep
power-down modes.
6.7.2 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 17.5.3 “Using the WWDT lock
6.7.3 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.
6.7.3.1 Power configuration in Active mode
Power consumption in Active mode is determined by the following configuration choices:
•
The SYSAHBCLKCTRL register controls which memories and peripherals are
running (
•
The power to various analog blocks (PLL, oscillators, the BOD circuit, and the flash
block) can be controlled at any time individually through the PDRUNCFG register
(
Table 54 “Power configuration register (PDRUNCFG, address 0x4004 8238) bit
).
•
The clock source for the system clock can be selected from the IRC (default), the
system oscillator, or the watchdog oscillator (see
and related registers).
•
The system clock frequency can be selected by the SYSPLLCTRL (
) and the
SYSAHBCLKDIV register (
•
The USART and CLKOUT use individual peripheral clocks with their own clock
dividers. The peripheral clocks can be shut down through the corresponding clock
divider registers.
6.7.4 Sleep mode
In Sleep mode, the system clock to the ARM Cortex-M0+ core is stopped and execution of
instructions is suspended until either a reset or an interrupt occurs.
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
Table 64.
Peripheral configuration in reduced power modes
Peripheral
Sleep mode
Deep-sleep
mode
Power-down
mode
Deep
power-down
mode