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

EPC-4680 Borad

<tbody> </tbody>
COM Name Device Node Remark
COM0 /dev/ttyS0  BT
COM1 /dev/ttyS2 Debug Port
COM2 /dev/ttyS4 485
COM3 /dev/ttyUSB0  
COM4 /dev/ttyUSB1   
COM5 /dev/ttyS1  
COM6 /dev/ttyS3   

 

 

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.