Datasheet
LPC435X_3X_2X_1X All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 4 — 19 August 2014 136 of 158
NXP Semiconductors
LPC435x/3x/2x/1x
32-bit ARM Cortex-M4/M0 microcontroller
13.2 Crystal oscillator
The crystal oscillator is controlled by the XTAL_OSC_CTRL register in the CGU (see
LPC43xx user manual).
The crystal oscillator operates at frequencies of 1 MHz to 25 MHz. This frequency can be
boosted to a higher frequency, up to the maximum CPU operating frequency, by the PLL.
The oscillator can operate in one of two modes: slave mode and oscillation mode.
• In slave mode, couple the input clock signal with a capacitor of 100 pF (C
C
in
Figure 42
), with an amplitude of at least 200 mV (RMS). The XTAL2 pin in this
configuration can be left unconnected.
• External components and models used in oscillation mode are shown in Figure 43,
and in Table 42
and Table 43. Since the feedback resistance is integrated on chip,
only a crystal and the capacitances CX1 and CX2 need to be connected externally in
case of fundamental mode oscillation (L, CL and RS represent the fundamental
frequency). Capacitance C
P
in Figure 43 represents the parallel package capacitance
and must not be larger than 7 pF. Parameters FC, CL, RS and CP are supplied by the
crystal manufacturer.
LCD_VD0 - - - - - - P4_1 RED0
LCD_LP P7_6 LCDLP P7_6 LCDLP P7_6 LCDLP P7_6 LCDLP
LCD_ENAB
/LCDM
P4_6 LCDENAB/
LCDM
P4_6 LCDENAB/
LCDM
P4_6 LCDENAB/
LCDM
P4_6 LCDENAB/
LCDM
LCD_FP P4_5 LCDFP P4_5 LCDFP P4_5 LCDFP P4_5 LCDFP
LCD_DCLK P4_7 LCDDCLK P4_7 LCDDCLK P4_7 LCDDCLK P4_7 LCDDCLK
LCD_LE P7_0 LCDLE P7_0 LCDLE P7_0 LCDLE P7_0 LCDLE
LCD_PWR P7_7 LCDPWR P7_7 LCDPWR P7_7 LCDPWR P7_7 LCDPWR
GP_CLKIN PF_4 LCDCLKIN PF_4 LCDCLKIN PF_4 LCDCLKIN PF_4 LCDCLKIN
Table 41. LCD panel connections for TFT panels
External
pin
TFT 12 bit (4:4:4
mode)
TFT 16 bit (5:6:5 mode) TFT 16 bit (1:5:5:5 mode) TFT 24 bit
LPC43xx
pin used
LCD
function
LPC43xx
pin used
LCD
function
LPC43xx pin
used
LCD
function
LPC43xx
pin used
LCD
function
Table 42. Recommended values for C
X1/X2
in oscillation mode (crystal and external
components parameters) low frequency mode
Fundamental oscillation
frequency
Maximum crystal series
resistance R
S
External load capacitors
C
X1
, C
X2
2 MHz < 200 33 pF, 33 pF
< 200 39 pF, 39 pF
< 200 56 pF, 56 pF
4 MHz < 200 18 pF, 18 pF
< 200 39 pF, 39 pF
< 200 56 pF, 56 pF
8 MHz < 200 18 pF, 18 pF
< 200 39 pF, 39 pF