Datasheet

LPC1311_13_42_43 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.
Product data sheet Rev. 5 — 6 June 2012 60 of 74
NXP Semiconductors
LPC1311/13/42/43
32-bit ARM Cortex-M3 microcontroller
In slave mode the input clock signal should be coupled by means of a capacitor of 100 pF
(Figure 34
), with an amplitude between 200 mV(RMS) and 1000 mV(RMS). This
corresponds to a square wave signal with a signal swing of between 280 mV and 1.4 V.
The XTALOUT pin in this configuration can be left unconnected.
External components and models used in oscillation mode are shown in Figure 35
and in
Table 21
and Table 22. Since the feedback resistance is integrated on chip, only a crystal
and the capacitances C
X1
and C
X2
need to be connected externally in case of
fundamental mode oscillation (the fundamental frequency is represented by L, C
L
and
R
S
). Capacitance C
P
in Figure 35 represents the parallel package capacitance and should
not be larger than 7 pF. Parameters F
OSC
, C
L
, R
S
and C
P
are supplied by the crystal
manufacturer.
Fig 34. Slave mode operation of the on-chip oscillator
Fig 35. Oscillator modes and models: oscillation mode of operation and external crystal
model used for C
X1
/C
X2
evaluation
LPC1xxx
XTALIN
C
i
100 pF
C
g
002aae788
002aaf424
LPC1xxx
XTALIN XTALOUT
C
X2
C
X1
XTAL
=
C
L
C
P
R
S
L