
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
53 of 487
NXP Semiconductors
UM10800
Chapter 5: LPC82x System configuration (SYSCON)
5.6.33 Power configuration register
The PDRUNCFG register controls the power to the various analog blocks. This register
can be written to at any time while the chip is running, and a write will take effect
immediately with the exception of the power-down signal to the IRC.
To avoid glitches when powering down the IRC, the IRC clock is automatically switched
off at a clean point. Therefore, for the IRC a delay is possible before the power-down state
takes effect.
The system oscillator requires typically 500
μ
s to start up after the SYSOSC_PD bit has
been changed from 1 to 0. There is no hardware flag to monitor the state of the system
oscillator. Therefore, add a software delay of about 500
μ
s before using the system
oscillator after power-up.
6
WDTOSC_PD
Watchdog oscillator wake-up configuration.
Changing this bit to powered-down has no effect
when the LOCK bit in the WWDT MOD register is
set. In this case, the watchdog oscillator is always
running.
1
0
Powered
1
Powered down
7
SYSPLL_PD
System PLL wake-up configuration
1
0
Powered
1
Powered down
11:8
-
Reserved. Always write these bits as 0b1101
0b1101
14:12 -
Reserved. Always write these bits as 0b110
0b110
15
ACMP
Analog comparator wake-up configuration
1
0
Powered
1
Powered down
31:16 -
-
Reserved
0
Table 53.
Wake-up configuration register (PDAWAKECFG, address 0x4004 8234) bit
description
…continued
Bit
Symbol
Value Description
Reset value
Table 54.
Power configuration register (PDRUNCFG, address 0x4004 8238) bit description
Bit
Symbol
Value
Description
Reset value
0
IRCOUT_PD
IRC oscillator output power
0
0
Powered
1
Powered down
1
IRC_PD
IRC oscillator power down
0
0
Powered
1
Powered down
2
FLASH_PD
Flash power down
0
0
Powered
1
Powered down