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X502N Reference Manual V2.2
9
2 Connectors Description
2.1 Serial connector
Function
Serial port
marking
COM1
～
2
Type
DB9
Pin define
Pin 1 location: The green frame on the right.
The COM1 ~ 2 serial ports are RS232 signals. The mapping
files in the Linux system are ttyS0 and ttyTHS2 in the / dev
directory.
TXD1 / RXD1 defaults to the kernel debug serial port,
which is used to output C-BOOT, U-BOOT, and Linux
kernel information. After the Linux kernel is started, it is
used as the serial port of the display terminal. TX1 / TX2
default serial port settings are: 115200bps, 8N1.
Pin
Signal
Pin
Signal
1
NC
2
RXD1
3
TXD1
4
RXD2
5
GND
6
TXD2
7
NC
8
NC
9
GND
Function
Serial port
marking
COM3
～
4
Type
DB9
Pin define
Pin 1 location: The green frame on the right.
The COM3 ~ 4 serial ports are RS232 signals. The mapping
files in the Linux system are ttyTHS1 and ttyTHS3 in the /
dev directory.
Pin
Signal
Pin
Signal
1
NC
2
RXD3
3
TXD3
4
RXD4
5
GND
6
TXD4
7
NC
8
NC
9
GND