User manual

LPCXpresso Experiment Kit - User’s Guide

Page 101

The UART signals from the LPC111x are made available on connector J18, see schematic below.

Signal GPIO_5-TXD carries the transmitted UART signal and GPIO_6-RXD is the received UART

signal. The experiments can take place on the pcb or on a breadboard. Resistor R62 has been added

for protection in case GPIO_6-RXD is programmed (by mistake) as an output. If that would happen,

R62 limits the currents to safe levels so no output gets damaged.

Figure 58 – J18, D2 and R62 on Schematic Page 7

Note orientation of the 6 pos connector of the cable. The black cable is positioned on pin 1 and is

ground. Figure 59 illustrates correct orientation when mounting the cable on the pcb.

Also note that the cable can actually power the system since the FTDI cable can supply a +5V voltage.

Diode D2 is included in case supply comes from multiple sources (for example, 2.1mm power jack J1

or USB connector J17).

Figure 59 – LPCXpresso Experiment Kit PCB with UART-to-USB Cable