Document No.: FT_000053
FT232R USB UART IC Datasheet Version 2.07
Clearance No.: FTDI# 38
7 Application Examples
The following sections illustrate possible applications of the FT232R. The illustrations have omitted pin
numbers for ease of understanding since the pins differ between the FT232RL and FT232RQ package
options.
7.1 USB to RS232 Converter
VCC
VCC
VCC
Ferrite Bead
TXD
RXD
TXDATA
RXDATA
RTS
1
2
3
4
TXD
RXD
VCC
GND
DB9M
USBDM
5
9
RTS#
CTS#
RTS#
CTS#
DTR#
DSR#
RI
DTR
270R
270R
4
8
3
7
2
6
1
USBDP
CTS
CTS
10nF
TXDATA
RTS
RXDATA
DSR
DCD
+
DTR#
DSR#
VCCIO
NC
DTR
FT232R
5
DSR
RESET#
DCD#
RI#
DCD#
DCD
RI
10
SHIELD
NC
SHIELD
RI#
CBUS0
CBUS1
CBUS2
CBUS3
CBUS4
OSCI
OSCO
SHDN#
GND
TXLED#
RXLED#
VCC
GPIO2
GPIO3
3V3OUT
100nF
4.7uF +
A
G
N
D
T
E
S
T
G
N
D
G
N
D
G
N
D
SLEEP#
100nF
GND
GND
GND
Figure 7.1 Application Example showing USB to RS232 Converter
An example of using the FT232R as a USB to RS232 converter is illustrated in Figure 7.1. In this
application, a TTL to RS232 Level Converter IC is used on the serial UART interface of the FT232R to
convert the TTL levels of the FT232R to RS232 levels. This level shift can be done using the popular “213”
series of TTL to RS232 level converters. These “213” devices typically 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. A useful feature of these devices is the SHDN# pin which can be used
to power down the device to a low quiescent current during USB suspend mode.
A suitable level shifting device is the Sipex SP213EHCA which is capable of RS232 communication at up
to 500k 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 Analogue Devices ADM213E, which are all
suitable for communication at up to 115.2k baud. If a higher baud rate is required, the Maxim
MAX3245CAI device is capable of RS232 communication rates up to 1Mbaud. Note that the MAX3245 is
not pin compatible with the 213 series devices and that the SHDN pin on the MAX device is active high
and should be connect to PWREN# pin instead of SLEEP# pin.
In example shown, the CBUS0 and CBUS1 have been configured as TXLED# and RXLED# and are being
used to drive two LEDs.
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