Figure 4 shows the UC232R “ChiPi” circuit schematic. For the UC232R the FT232RL has been used in combination
with a Zywyn ZT213LEEA to make a USB to RS232 converter. The Zywyn ZT213LEEA is used to make the TTL to
RS232 level conversion and is capable of RS232 communication at up to 250 kilobaud baud.
VCC
U1
VCC
VCC
TXD
1
TXD
DTR#
OSCO
OSCI
TEST
AGND
AVCC
CBUS0
CBUS1
GND
VCC5I
20
28
27
26
25
24
23
22
21
U2
DTR#
2
DTR
TXDATA
RTS
GND
1
T3O
T4O
2
T1O
28
RTS#
3
RTS#
R3I
3
T2O
27
CTS
GND
4
VCCIO
RXD
RI#
R3O
RXDATA
RXD
RTS#
TXD
DSR#
26
4
R2I
CTS#
RXD
5
6
SD
5
R2O
25
SLEEP#
RI#
7
GND
EN
6
7
24
T2I
T1I
R4I
23
RI
Figure 4 - UC232R “ChiPi” USB to RS232 Converter Cable Circuit Schematic
8
VCC3I
DSR#
VCC
R4O
8
DSR
VCC
GND
22
R1O
RI#
DCD#
10
DCD#
RESET#
19
9
10
C4
10nF
R1I
GND
T3I
R5O
20
19
DTR#
CTS#
11
CTS#
GND
18
DCD#
**
SHIELD
13
CBUS2
USBDM
16
12
15
C1+
V-
17
14
CBUS3
FT232R
FB1
13
USBDP
V+
C2-
16
14
C1-
ZT213E
C2+
15
C7
C6
10nF
GND
1
2
C10
10nF
C5
10nF
10nF
GND
VCC
C8
GND
USB
CN-USB
CN1
FERRITE BEAD
VCC
5. UC232R Circuit Schematic
1
2
3
4
*
C1
10nF
GND
10nF
C9
GND
4.7uF
NOTES
+
47pF
10nF
5
C2
*
47pF
10nF
C3
*
FT232R APPLICATION SCHEMATIC
GND
GND
GND
*
Optional - may be
required to reduce
EMI emissions
"ChiPi"
MINIMAL COMPONENT USB SERIAL ADAPTOR
SHIELD
**
**
The shield wire
of the USB cable
should be soldered
to the DB9 outer can
UC232R “ChiPi” Minimum Component FT232RL USB to RS232 Converter Cable
Datasheet Version 0.90
SLEEP#
12
CBUS4
VCC3O
17
11
VCC
R5I
18
DCD
10
DSR#
9
T4I
21
RI
DTR
CTS
TXDATA
RTS
RXDATA
DSR
DCD
5
9
4
8
3
7
2
6
1
DB9M
PL1
© Future Technology Devices International Ltd. 2005
Page 8
FTDI [ FUTURE TECHNOLOGY DEVICES INTERNATIONAL LTD. ]
