For completeness the following pictures show the use of an RS232 level shifter.
GND
1
2
3
4
5
6
7
8
9
C1
0.1µ
F
C2
0.1µ
F
C3
0.1µ
F
C4
0.1µ
F
C5
0.1µ
F
RS232 Level Shifter
RS232 Out
DB
9 f
em
al
e
3.3V
Vcc
GND
T1O
R1I
R1O
T1I
T2I
R2O
C1+
V+
C1-
C2+
C2-
V-
T2O
R2I
MAX3232
Tx
Rx
GND
1
2
3
4
5
6
7
8
9
C1
0.1µ
F
C2
0.1µ
F
C3
0.1µ
F
C4
0.1µ
F
C5
0.1µ
F
RS232 Level Shifter
RS232 Out
DB
9 f
em
al
e
3.3V
Vcc
GND
T1O
R1I
R1O
T1I
T2I
R2O
C1+
V+
C1-
C2+
C2-
V-
T2O
R2I
MAX3232
Tx
Rx
Figure 7: RS232 level shifter for minimum configurations
Remarks:
•
Place C1 to C5 (here: 0.1µF) close to MAX3232. For capacity values see
datasheet of actual component used.
•
Use 3.3V level shifter (MAX3232 or equivalent).
V1.5 – Dec-09
User’s Manual
Page 13 of 37
