Document No.: FT_000053
FT232R USB UART IC Datasheet Version 2.07
Clearance No.: FTDI# 38
7.4 USB to MCU UART Interface
Vcc
Vcc
Ferrite Bead
1
2
3
4
10nF
+
VCC
USBDM
RTS#
USBDP
CTS#
VCCIO
NC
RESET#
SHIELD
GND
Vcc
3V3OUT
100nF
4.7uF +
A
G
N
D
G
N
D
G
N
D
G
N
D
T
E
S
T
NC
RI#
OSCI
CBUS0
OSCO
CBUS1
CBUS2
CBUS3
CBUS4
PWREN#
10K
I/O
12MHz
OUT
CLK_IN
Vcc
RTS#
DTR#
RXD
TXD
TXD
RXD
CTS#
5
FT232R
Microcontroller
DSR#
DCD#
100nF
GND
GND
GND
Figure 7.4 USB to MCU UART Interface
An example of using the FT232R as a USB to Microcontroller (MCU) UART interface is shown in Figure
7.4. In this application the FT232R uses TXD and RXD for transmission and reception of data, and RTS# /
CTS# signals for hardware handshaking. Also in this example CBUS0 has been configured as a 12MHz
output to clock the MCU.
Optionally, RI# could be connected to another I/O pin on the MCU and used to wake up the USB host
controller from suspend mode. If the MCU is handling power management functions, then a CBUS pin can
be configured as PWREN# and would also be connected to an I/O pin of the MCU.
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30
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