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UM10503
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© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
177 of 1441
NXP Semiconductors
UM10503
Chapter 13: LPC43xx/LPC43Sxx Clock Generation Unit (CGU)
13.6.3 PLL0USB registers
The PLL0USB provides a dedicated clock to the High-speed USB0 interface.
See
for instructions on how to set up the PLL0USB.
13.6.3.1 PLL0USB status register
13.6.3.2 PLL0USB control register
1
BYPASS
Configure crystal operation or external-clock input
pin XTAL1. Do not change the BYPASS and
ENABLE bits in one write-action: this will result in
unstable device operation!
0
R/W
0
Crystal. Operation with crystal connected (default).
1
Bypass mode. Use this mode when an external
clock source is used instead of a crystal.
2
HF
Select frequency range
1
R/W
0
Low. Oscillator low-frequency mode (crystal or
external clock source 1 to 20 MHz). Between 15
MHz and 20 MHz, the state of the HF bit is don’t
care.
1
High. Oscillator high-frequency mode; crystal or
external clock source 15 to 25 MHz. Between 15
MHz and 20 MHz, the state of the HF bit is don’t
care.
31:3
-
Reserved
-
-
Table 127. XTAL_OSC_CTRL register (XTAL_OSC_CTRL, address 0x4005 0018) bit
description
Bit
Symbol
Value
Description
Reset
value
Access
Table 128. PLL0USB status register (PLL0USB_STAT, address 0x4005 001C) bit description
Bit
Symbol
Description
Reset
value
Access
0
LOCK
PLL0 lock indicator
0
R
1
FR
PLL0 free running indicator
0
R
31:2
-
Reserved
-
Table 129. PLL0USB control register (PLL0USB_CTRL, address 0x4005 0020) bit description
Bit
Symbol
Value
Description
Reset
value
Access
0
PD
PLL0 power down
1
R/W
0
PLL0 enabled
1
PLL0 powered down
1
BYPASS
Input clock bypass control
1
R/W
0
CCO clock sent to post-dividers. Use this
in normal operation.
1
PLL0 input clock sent to post-dividers
(default).