RS-232 Serial Communications
Technical Summary, Rev. 2
Freescale Semiconductor
2-7
Preliminary
2.3 RS-232 Serial Communications
The 56F8367EVM provides an RS-232 interface by the use of an RS-232 level converter, Maxim
MAX3245EEAI, designated as U4. Refer to the RS-232 schematic diagram in
RS-232 level converter transitions the SCI port’s +3.3V signal levels to RS-232-compatible
signal levels and connects to the host’s serial port via connector P2. RTS/CTS flow control is
provided on JG11 as a jumper, but could be implemented using uncommitted GPIO signals. The
SCI port #0 signals can be isolated from the RS-232 level converter by removing the jumpers in
JG9; see
. The pin-out of connector P2 is listed in
. The RS-232 level
converter/transceiver can be disabled by placing a jumper at JG10.
MC56F8367
RS-232
Level Converter
Interface
TXD0
RXD0
R1 in
T1 out
T1 in
R1 out
FORCEOFF
JG10
6
3
2
7
8
4
5
x
1
9
+3.3V
Jumper Removed:
Enable RS-232
P2
JG9
1
2
3
4
1
2
Jumper Pin 1-2:
Disable RS-232
R2 in
T2 out
JG11
1
2
T2 in
R2 out
RTS
CTS
TXD
RXD
Figure 2-3. Schematic Diagram of the RS-232 Interface
Table 2-1. SCI #0 Jumper Options
JG9
Pin #
Signal
Pin #
Signal
1
TXD0
2
RS-232 TXD
3
RXD0
4
RS-232 RXD