Document No.: FT_000060
FT4232H QUAD HIGH SPEED USB TO MULTIPURPOSE UART/MPSSE IC
Datasheet Version 2.09
Clearance No.: FTDI#78
3.4 Configured Pins
The following sections describe the function of the configurable pins referred to in Table
which is
determined by how the FT4232H is configured.
3.4.1 FT4232H pins used as an asynchronous serial interface
The FT4232H any of the 4 channels can be configured as an asynchronous serial UART interface
(RS232/422/485). When configured in this mode, the pins used and the descriptions of the signals are
shown in Table 3.5.
Channel
A
Pin No.
16
17
18
19
21
22
23
Channel
B
Pin No.
26
27
28
29
30
32
33
Channel
C
Pin No.
38
39
40
41
43
44
45
Channel
D
Pin No.
48
52
53
54
55
57
58
TXD
RXD
RTS#
CTS#
DTR#
DSR#
DCD#
OUTPUT
INPUT
OUTPUT
INPUT
OUTPUT
INPUT
INPUT
TXD = transmitter output
RXD = receiver input
RTS# = Ready To send handshake
output
CTS# = Clear To Send handshake input
DTR# = Data Transmit Ready modem
signaling line
DSR# = Data Set Ready modem
signaling line
DCD# = Data Carrier Detect modem
signaling line
RI# = Ring Indicator Control Input.
When the Remote Wake up option is
enabled in the EEPROM, taking RI# low
can be used to resume the PC USB Host
controller from suspend.
(see note 1, 2 and 3)
TXDEN = (TTL level). For use with RS485
level converters.
Table 3.5 Channel A,B,C and Channel D Asynchronous Serial Interface Configured Pin Descriptions
Name
Type
RS232 Configuration Description
24
34
46
59
RI#/
TXDEN
INPUT/OUTPUT
Notes
1.
2.
When using remote wake-up, ensure the resistors are pulled-up in suspend. Also ensure
peripheral designs do not allow any current sink paths that may partially power the peripheral.
If remote wake-up is enabled, a peripheral is allowed to draw up to 2.5mA in suspend. If remote
wake-up is disabled, the peripheral must draw no more than 500uA in suspend.
3. If a Pull-down is enabled, the 4232H will not wake up from suspend.
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