DRAFT
DRAFT DRAFT DR
DRAFT DRAFT DRAFT
D
RAF
DRAFT DRAFT DRA
FT D
RAFT DR
AFT D
DRA
FT DRAFT DRAFT
D
RAFT
DRAFT
D
RAFT
DRA
UM10601
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2012. All rights reserved.
Preliminary user manual
Rev. 1.0 — 7 November 2012
45 of 313
NXP Semiconductors
UM10601
Chapter 5: LPC800 Reduced power modes and Power Management
5.6.3 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 to wake
up from Deep power-down mode if the wake-up pin is used for other purposes and the
wake-up function is not available.
Table 45.
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.
0
0
Disabled.
1
Enabled.