Datasheet

LPC111X All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 9.2 — 26 March 2014 99 of 127
NXP Semiconductors
LPC1110/11/12/13/14/15
32-bit ARM Cortex-M0 microcontroller
12.4 XTAL Printed Circuit Board (PCB) layout guidelines
The crystal should be connected on the PCB as close as possible to the oscillator input
and output pins of the chip. Take care that the load capacitors C
X1
, C
X2
, and C
X3
in case
of third overtone crystal usage have a common ground plane. The external components
must also be connected to the ground plain. Loops must be made as small as possible in
order to keep the noise coupled in via the PCB as small as possible. Also parasitics
should stay as small as possible. Values of C
X1
and C
X2
should be chosen smaller
accordingly to the increase in parasitics of the PCB layout.
12.5 Standard I/O pad configuration
Figure 51 shows the possible pin modes for standard I/O pins with analog input function:
• Digital output driver
• Digital input: Pull-up enabled/disabled
• Digital input: Pull-down enabled/disabled
• Digital input: Repeater mode enabled/disabled
• Digital output: Pseudo open-drain mode enable/disabled
• Analog input