Datasheet

LPC2458 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 4.1 — 15 October 2013 69 of 81
NXP Semiconductors
LPC2458
Single-chip 16-bit/32-bit micro
14.2 Crystal oscillator XTAL input and component selection
The input voltage to the on-chip oscillators is limited to 1.8 V. If the oscillator is driven by a
clock in slave mode, it is recommended that the input be coupled through a capacitor with
C
i
= 100 pF. To limit the input voltage to the specified range, choose an additional
capacitor to ground C
g
which attenuates the input voltage by a factor C
i
/ (C
i
+ C
g
). In
slave mode, a minimum of 200 mV (RMS) is needed.
Fig 25. LPC2458 USB OTG port configuration: USB port 1 host, USB port 2 host
USB_UP_LED1
USB_D+1
USB_D−1
USB_PWRD1
USB_PWRD2
15 kΩ
15 kΩ 15 kΩ
15 kΩ
LPC24XX
USB-A
connector
USB-A
connector
33 Ω
33 Ω
33 Ω
33 Ω
002aad596
V
DD
USB_UP_LED2
V
DD
USB_OVRCR1
USB_OVRCR2
USB_PPWR1
LM3526-L
ENA
ENB
IN
5 V
FLAGA
OUTA
OUTB
FLAGB
V
DD
V
DD
D+
D−
D+
D−
V
BUS
V
BUS
USB_PPWR2
USB_D+2
USB_D−2
V
SSIO,
V
SSCORE
V
SSIO,
V
SSCORE
Fig 26. Slave mode operation of the on-chip oscillator
LPC2xxx
XTAL1
C
i
100 pF
C
g
002aae718