DS_FT312D USB ANDROID HOST IC Datasheet
Version 1.1
Document No.: FT_000816 Clearance No.: FTDI# 331
8.2 USB to RS232 Converter
5V
3V3
3V3
REGULATOR
5V Power to USB
VCC
Ferrite
Bead
DB9
VCCIO
TXD
1
UART_TXD
3
2
RESET#
TXD
RXD
27R
27R
2
3
USBDM
USBDP
RXD
RTS
CTS
UART_RXD
UART_RTS#
UART_CTS#
RS232
LEVEL
CONVERTER
4
RTS#
CTS#
7
8
5
47pF
47pF
SHIELD
10
FT312D
5
TX_ACTIVE
100nF
GND
SHIELD
GND
AVCC
LED
620R
3V3
USB_ERROR
VREGOUT
D
N
3V3
G
100nF
+
4.7uF
100nF
GND
GND
Figure 8.2Application Example showing USB to RS232 Converter
An example of using the FT312D as a USB to RS232 converter is illustrated in Figure 8.2. In this
application, a TTL to RS232 Level Converter IC is used on the serial UART interface of the FT312D to
convert the TTL levels of the FT312D to RS232 levels. This level shift can be done using line drivers from
a variety of vendors e.g. Zywyn.
A suitable level shifting device is the Zywyn ZT3243F which is capable of RS232 communication at up to
1000k baud.
The unused pins may be left unterminated.
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