FT232R USB UART I.C. Datasheet Version 1.04

© Future Technology Devices International Ltd. 2005

Page 23

8. Example Interface Configurations

As in the Device Configurations section, please note that pin numbers on the FT232R chip in this section have

deliberately been left out as they vary between the FT232RL and FT232RQ versions of the device. All of these

configurations apply to both package options for the FT232R device. Please refer to Section 4 for the package option

pin-out and signal descriptions.

8.1 USB to RS232 Converter Configuration

Figure 15 - Example USB to RS232 Converter Configuration

Figure 15 illustrates how to connect an FT232R as a USB to RS232 converter. A TTL – RS232 Level Converter I.C. is

used on the serial UART of the FT232R to make the RS232 level conversion. This, for example can be done using the

popular “213” series of TTL to RS232 level converters. These devices have 4 transmitters and 5 receivers in a 28-LD

SSOP package and feature an in-built voltage converter to convert the 5V (nominal) VCC to the +/- 9 volts required by

RS232. An important feature of these devices is the SHDN# pin which can power down the device to a low quiescent

current during USB suspend mode.

An example of a device which can be used for this is a Sipex SP213EHCA which is capable of RS232 communication

at up to 500kΩ baud. If a lower baud rate is acceptable, then several pin compatible alternatives are available

such as the Sipex SP213ECA , the Maxim MAX213CAI and the Analog Devices ADM213E, which are all good for

communication at up to 115,200 baud. If a higher baud rate is desired, use a Maxim MAX3245CAI part which is

capable of RS232 communication at rates of up to 1M baud. The MAX3245 is not pin compatible with the 213 series

devices, also its SHDN pin is active high, so connect it to PWREN# instead of SLEEP#.

In the above example CBUS0 and CBUS1 have been configured as TXLED# and RXLED#, and are being used to

drive two LEDs.

FT232R

A

G

N

D

G

N

D

G

N

D

G

N

D

T

E

S

T

100nF

3V3OUT

VCCIO

NC

RESET#

NC

+

100nF

10nF

Vcc

TXD

RXD

RTS#

CTS#

DTR#

DSR#

DCD#

RI#

CBUS0

CBUS3

CBUS2

CBUS1

GPIO2

GPIO3

USBDP

USBDM

VCC

1

2

3

4

5

OSCI

OSCO

CBUS4

SLEEP#

Ferrite

Bead

+

4.7uF

Vcc

Vcc

270R

270R

SHIELD

5

9

4

8

3

7

2

6

1

TXDATA

RXDATA

RTS

CTS

DTR

DSR

DCD

RI

SHIELD

GND

10

DB9M

TXDATA

RXDATA

RTS

CTS

DTR

DSR

DCD

RI

TXD

RXD

RTS#

CTS#

DTR#

DSR#

DCD#

RI#

TXLED#

RXLED#

SHDN#

Vcc