Copyright © 2015 Future Technology Devices International Limited

27

FT234XD USB TO BASIC UART IC

Version 1.2

Document No.: FT_000753 Clearance No.: FTDI#324

When connected to a USB compliant dedicated charging port (DCP, as opposed to a standard USB host)

the device USB signals will be shorted together and the device suspended. The BCD charger signal will

bring the LTC4053 out of suspend and allow battery charging to start. The charge current in the example

above is 1A as defined by the resistance on the PROG pin.

For more configuration options of the LTC4053 refer to:

AN_175_Battery Charging Over USB

Note: If the FT234XD is connected to a standard host port such that the device is enumerated the battery

charge detection signal is inactive as the device will not be in suspend.

7.5 LED Interface

The CBUS0 I/O pin can be configured to drive an LED. The FT234XD has 3 configuration options for

driving LEDs from the CBUS. These are TXLED#, RXLED#, and TX&RXLED#. Refer to Section 3.2 for

configuration options.

FT234XD

CBUS0

VCCIO

270R

TX &

RXLED#

Figure 7.5 Single LED Configuration

An example of using the FT234XD to drive an LED is shown in Figure 7.57. In this example the CBUS0 pin

is used to indicate when data is being transmitted or received by the device (TX&RXLED). In this

configuration the FT234XD will drive only a single LED.