SIM345 EVB User Guide
SIM345-EVB_UGD_V1.02
15.02.2008
11
3.5 RS232 Interface
Figure 8: UART1 Serial Port
Main port UART1——A full functional seven-wires serial port
Auxiliary serial port UART2——An auxiliary three-wires serial interface
Main serial
port
（
UART1
）
:
Pin
Signal
I/O
Description
1 DCD
O
Data carrier detection
2 TXD1 O
Transmit data
3 RXD1 I
Receive data
4 DTR
I
Data Terminal Ready
5 GND
GND
7 RTS
I
Request to Send
8 CTS
O
Clear to Send
9 RI
O
Ring Indicator
Figure 9: UART2 Serial Port
