Difference between revisions of "How to use UART"
From ESS-WIKI
Yunjin.jiang (talk | contribs) |
Yunjin.jiang (talk | contribs) |
||
| Line 50: | Line 50: | ||
| − | < | + | <span style="color:#FF0000;">'''Note : '''</span> |
| + | |||
| + | 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. | ||
Revision as of 10:29, 25 March 2019
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
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.