
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
67 of 487
NXP Semiconductors
UM10800
Chapter 6: LPC82x Reduced power modes and power management
6.6.3 Deep power-down control register
The Deep power-down control register controls the low-power oscillator that can be used
by the self-wake-up timer to wake up from Deep power-down mode. In addition, this
register configures the functionality of the WAKEUP pin (pin PIO0_4).
The bits in the register not used for deep power-down control (bits 31:4) can be used for
storing additional data which are retained in Deep power-down mode in the same way as
registers GPREG0 to GPREG3.
Remark:
If there is a possibility that the external voltage applied on pin V
DD
drops below
2.2 V during Deep power-down, the hysteresis of the WAKEUP input pin has to be
disabled in this register before entering Deep power-down mode in order for the chip to
wake up.
Remark:
Enabling the low-power oscillator in Deep power-down mode increases the
power consumption. Only enable this oscillator if you need the self-wake-up timer to wake
up the part from Deep power-down mode. You may need the self-wake-up timer if the
wake-up pin is used for other purposes and the wake-up function is not available.
Table 62.
General purpose registers 0 to 3 (GPREG[0:3], address 0x4002 0004 (GPREG0) to
0x4002 0010 (GPREG3)) bit description
Bit
Symbol
Description
Reset
value
31:0
GPDATA
Data retained during Deep power-down mode.
0x0
Table 63.
Deep power down control register (DPDCTRL, address 0x4002 0014) bit description
Bit
Symbol
Value
Description
Reset
value
0
WAKEUPHYS
WAKEUP pin hysteresis enable
0
0
Disabled. Hysteresis for WAKEUP pin disabled.
1
Enabled. Hysteresis for WAKEUP pin enabled.
1
WAKEPAD_
DISABLE
WAKEUP pin disable. Setting this bit disables the wake-up pin, so it can be
used for other purposes.
Remark:
Never set this bit if you intend to use a pin to wake up the part from
Deep power-down mode. You can only disable the wake-up pin if the
self-wake-up timer is enabled and configured.
Remark:
Setting this bit is not necessary if Deep power-down mode is not
used.
0
0
Enabled. The wake-up function is enabled on pin PIO0_4.
1
Disabled. Setting this bit disables the wake-up function on pin PIO0_4.
2
LPOSCEN
Enable the low-power oscillator for use with the 10 kHz self-wake-up timer
clock. You must set this bit if the CLKSEL bit in the self-wake-up timer CTRL
bit is set.
Do not enable the low-power oscillator if the self-wake-up timer is clocked by
the divided IRC or the external clock input.
0
0
Disabled.
1
Enabled.