How to use UART
From ESS-WIKI
Contents
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
| 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.