UM10360 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
User manual Rev. 3 — 19 December 2013  49 of 841
NXP Semiconductors
UM10360
Chapter 4: LPC176x/5x Clocking and power control
[1] Reset Value reflects the data stored in used bits only. It does not include reserved bits content.
 
4.6.2 PLL1 Control register (PLL1CON - 0x400F C0A0)
The PLL1CON register contains the bits that enable and connect PLL1. Enabling PLL1 
allows it to attempt to lock to the current settings of the multiplier and divider values. 
Connecting PLL1 causes the USB subsystem to run from the PLL1 output clock. Changes 
to the PLL1CON register do not take effect until a correct PLL feed sequence has been 
given (see Section 4.6.6
 and Section 4.6.3).
PLL1CFG PLL1 Configuration Register. Holding register 
for updating PLL1 configuration values. Values 
written to this register do not take effect until a 
valid PLL1 feed sequence has taken place.
R/W 0 0x400F C0A4
PLL1STAT PLL1 Status Register. Read-back register for 
PLL1 control and configuration information. If 
PLL1CON or PLL1CFG have been written to, 
but a PLL1 feed sequence has not yet occurred, 
they will not reflect the current PLL1 state. 
Reading this register provides the actual values 
controlling PLL1, as well as PLL1 status.
RO 0 0x400F C0A8
PLL1FEED PLL1 Feed Register. This register enables 
loading of PLL1 control and configuration 
information from the PLL1CON and PLL1CFG 
registers into the shadow registers that actually 
affect PLL1 operation.
WO NA 0x400F C0AC
Table 29. PLL1 registers
Name Description Access Reset 
value
[1]
Address
Fig 10. PLL1 block diagram
100416
PLL output 
clock
Divide by 2P
Phase 
Detector
PLOCK 
PLLSTAT[10]
Current-
Controlled 
Oscillator
Fcco
PSEL 
PLLSTAT[6:5]
PLL input 
clock
Divide by M
MSEL 
PLLSTAT[4:0]