Realtimes Beijing Technology Co.,LTD
Manual for RTSO-9001 V2.0
28
Function
Serial communication connector
The board
level
RTSO-9001T
（
The upper plate
）
Marking
J4
Type
2.0mm ,2x5Pin Double row pins
Descriptio
n
RTSO-9001 provides two RS232/RS422/RS485 serial communication
interfaces. Users can use BIT1, BIT2 and BIT3 on the dial code switch
SW2 to select the mode.
Pin define
Mode6
232 one way, 422 one way
Dial Switch
State
Pin
Signal
Pin
Signal
110
BIT1 OFF
BIT2 ON
BIT3 ON
1
U0_232_TX
2
U0_232_RX
3
U0_232_RTS
4
U0_232_CTS
5
GND
6
GND
7
U1_TX_P
8
U1_RX_P
9
U1_TX_N
10
U1_RX_N
Mode7
Serial port to close
Dial Switch
State
Pin
Signal
Pin
Signal
111
BIT1 ON
BIT2 ON
BIT3 ON
1
NC
2
NC
3
NC
4
NC
5
GND
6
GND
7
NC
8
NC
9
NC
10
NC
Pin-1
：
The green box on the right.
Pin-2
：
The red box on the right.
Note 1: Loop mode causes boot to fail to boot. Disable this mode.
Note 2: Since 485 is a half duplex bus, user program is required to
control RTS signal for sending and receiving switch
Serial port 0 is the debugging serial port. It is not recommended to use
485
Note 3:232 mode supports hardware current control
The mapping file of UART0~ UART1 in Linux system is ttyS0 and
ttyTHS2 in /dev directory
By default, UART0 is a kernel debugging serial port, which is used to
output c-boot, U-boot, and Linux kernel information. After the Linux
kernel is started, UART0 is used as an explicit control terminal serial
port. TX2 default serial port setting is: 115200bps, 8N1
