
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
64 of 487
NXP Semiconductors
UM10800
Chapter 6: LPC82x Reduced power modes and power management
1. Sleep mode:
The sleep mode affects the ARM Cortex-M0+ core only. Peripherals and memories
are active.
2. Deep-sleep and power-down modes:
The Deep-sleep and power-down modes affect the core and the entire system with
memories and peripherals. Before entering deep-sleep or power-down, you must
switch the main clock to the IRC to provide a clock signal that can be shut down
cleanly.
a. In Deep-sleep mode, the peripherals receive no internal clocks. The flash is in
standby mode. The SRAM memory and all peripheral registers as well as the
processor maintain their internal states. The WWDT, WKT, and BOD can remain
active to wake up the system on an interrupt.
b. In Power-down mode, the peripherals receive no internal clocks. The internal
SRAM memory and all peripheral registers as well as the processor maintain their
internal states. The flash memory is powered down. The WWDT, WKT, and BOD
can remain active to wake up the system on an interrupt.
3. Deep power-down mode:
For maximal power savings, the entire system is shut down except for the general
purpose registers in the PMU and the self-wake-up timer. Only the general purpose
registers in the PMU maintain their internal states. The part can wake up on a pulse
on the WAKEUP pin or when the self-wake-up timer times out. On wake-up, the part
reboots.
Remark:
The part is in active mode when it is fully powered and operational after booting.
6.5.1 Wake-up process
If the part receives a wake-up signal in any of the reduced power modes, it wakes up to
the active mode.
See these links for related registers and wake-up instructions:
•
To configure the system after wake-up:
Table 53 “Wake-up configuration register
(PDAWAKECFG, address 0x4004 8234) bit description”
•
To use external interrupts for wake-up:
Table 50 “Start logic 0 pin wake-up enable
register 0 (STARTERP0, address 0x4004 8204) bit description”
and
•
To enable external or internal signals to wake up the part from Deep-sleep or
Power-down modes:
Table 51 “Start logic 1 interrupt wake-up enable register
(STARTERP1, address 0x4004 8214) bit description”
•
To configure the USART to wake up the part:
Section 13.3.2 “Configure the USART
•
For configuring the self-wake-up timer:
•
For a list of all wake-up sources: