FT2232C Dual USB UART / FIFO I.C.
Figure 14 - USB <=> Dual Port RS232 Converter Configuration
VCC
Figure 14 illustrates how to connect the
FT2232C, when both channels A and B are
configured as 232-style UART interfaces, to
two TTL – RS232 Level Converter I.C.’s to
make a USB <=> Dual Port RS232 converter
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.
SP213EHCA
FT2232C
SLEEP# (ACBUS1)
DB9-M
13
24
23
22
21
20
19
17
16
15
25
7
11
2
RS232 Channel A
SHDN#
VCC
T1Out
R4In
3
TXD (ADBUS0)
RXD (ADBUS1)
RTS# (ADBUS2)
RTS# (ADBUS3)
DTR# (ADBUS4)
DSR# (ADBUS5)
DCD# (ADBUS6)
RI# (ADBUS7)
T1In
TXD_A
22
20
8
2
23
1
R4Out
T3In
RXD_A
7
T3Out
R1In
RTS_A
9
8
R1Out
T2In
CTS_A
3
4
6
T2Out
R2In
DTR_A
5
4
6
R2Out
R3Out
R5Out
DSR_A
27
18
28
1
26
19
R3In
DCD_A
9
R5In
RI_A
21
12
5
TXDEN (ACBUS0)
GND
T4In
C1+
T4Out
C2+
15
0.1uF
0.1uF
14
17
0.1uF
16
C1-
C2-
V+
G
N
D
V
C
C
13
V-
0.1uF
VCC
11
10
The device used in the example above
is a 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 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#. Dual RS232 level converters
such as the Maxim MAX3187 may also be a
suitable alternative.
0.1uF
VCC
VCC
SP213EHCA
DB9-M
29
40
39
38
37
36
35
33
32
30
25
7
11
2
SLEEP# (BCBUS1)
TXD (BDBUS0)
RXD (BDBUS1)
RTS# (BDBUS2)
CTS# (BDBUS3)
DTR# (BDBUS4)
DSR# (BDBUS5)
DCD# (BDBUS6)
RI# (BDBUS7)
SHDN#
T1In
VCC
T1Out
R4In
RS232 Channel B
3
TXD_B
22
20
8
2
23
1
R4Out
T3In
RXD_B
7
RTS_B
T3Out
R1In
9
8
R1Out
T2In
CTS_B
3
6
4
T2Out
R2In
DTR_B
5
4
6
DSR_B
R2Out
R3Out
R5Out
27
18
28
1
26
19
DCD_B
R3In
9
RI_B
R5In
5
21
12
TXDEN (BCBUS0)
GND
T4In
C1+
T4Out
C2+
15
41
PWREN#
0.1uF
14
17
16
C1-
G
C2-
V+
V
C
C
13
V-
N
D
0.1uF
VCC
11
10
0.1uF
VCC
DS2232C Version 1.2
© Future Technology Devices International Ltd. 2004
Page 29 of 54
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