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X503N Reference Manual V2.2
9
2 Connectors Description
2.1 Serial connector
Function
Serial port
marking
COM1
Type
DB9
Pin define
Pin 1 location: The green frame on the right.
The COM1 serial port that leads out is 3.3V RS232 logic
level. The mapping file in the Linux system is ttyS0 in the
/dev directory.
COM1 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
NC
5
GND
6
NC
7
NC
8
NC
9
NC
Function
Serial port
marking
COM2
Type
DB9
Pin define
Pin 1 location: The green frame on the right.
The COM2 serial port that leads out is 3.3V RS232 logic
level. The mapping file in the Linux system is ttyTHS2 in
the /dev directory.
Pin
Signal
Pin
Signal
1
NC
2
RXD2
3
TXD2
4
NC
5
GND
6
NC
7
NC
8
NC
9
NC
