How to use UART

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Overview

The Android/Linux UART/serial port access from user is through the tty-devices. The tty-devices have different names depending on UART driver on different board.

RS-485

RS-485 uses half-duplex communication, which means that one medium is shared for transmitting and receiving data. Therefore the system needs to control the RS-485 transceiver's transmit mode. Usually the UART RTS signal is used to switch the transmitter on and off.

Boards

RSB4680 Borad

COM Name Device Node Remark
COM0 /dev/ttyS0
for BT Data
COM1
/dev/ttyS1

COM2
/dev/ttyS2
Debug Port
COM3
/dev/ttyS3

COM4
/dev/ttyS4
Supprot RSB485
COM5
/dev/ttyUSB0
Usb to Uart
COM6 /dev/ttyUSB1
Usb to Uart



Note : 

1. Only COM1、COM2、COM3、COM4、COM5 and COM6 are designed for custom using.

2. Only COM4 support RSB485.

3. COM2 is designed as debug port default.