Difference between revisions of "How to use UART RK3568"

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Usually the UART RTS signal is used to switch the transmitter on and off.
 
Usually the UART RTS signal is used to switch the transmitter on and off.
  
−
= '''Boards''' =
+
<h1> <b>Boards</b> </h1>
 +
<h2> RSB-4810 Borad </h2>
 +
<table border="1" cellpadding="1" cellspacing="1">
  
 +
<tr>
 +
<td> <b>COM Name</b>
 +
</td>
 +
<td> <b>Device Node</b>
 +
</td>
 +
<td> <b>Remark</b>
 +
</td></tr>
 +
<tr>
 +
<td> COM1
 +
</td>
 +
<td> /dev/ttyS4
 +
</td>
 +
<td> support RS232, no flow control
 +
</td></tr>
 +
<tr>
 +
<td> COM2
 +
</td>
 +
<td> /dev/ttyS7
 +
</td>
 +
<td> support RS232, no flow control
 +
</td></tr>
 +
<tr>
 +
<td> COM3
 +
</td>
 +
<td> /dev/ttyUSB2
 +
</td>
 +
<td> support RS232 and RS485
 +
</td></tr>
 +
<tr>
 +
<td> COM4
 +
</td>
 +
<td> /dev/ttyUSB3
 +
</td>
 +
<td> support RS232&#160;and RS485
 +
</td></tr>
 +
<tr>
 +
<td> COM5
 +
</td>
 +
<td> /dev/ttyUSB0
 +
</td>
 +
<td> support RS232
 +
</td></tr>
 +
<tr>
 +
<td> COM6
 +
</td>
 +
<td> /dev/ttyUSB1
 +
</td>
 +
<td> support RS232
 +
</td></tr></table>
 +
<p><b>Note&#160;:&#160;</b>
 +
</p><p>1. Only USB2COM2 and&#160;USB2COM3&#160;support RS485 mode.
 +
</p><p>2. COM2 is designed as debug port default.&#160;
 +
</p>
 +
<h2> KEDGE-350 Borad </h2>
 +
<table border="1" cellpadding="1" cellspacing="1">
  
−
== RSB-4810 Borad ==
+
<tr>
 +
<td> <b>COM Name</b>
 +
</td>
 +
<td> <b>Device Node</b>
 +
</td>
 +
<td> <b>Remark</b>
 +
</td></tr>
 +
<tr>
 +
<td> COM0
 +
</td>
 +
<td> /dev/ttyS3
 +
</td>
 +
<td> RS232 2-wire and RS485
 +
</td></tr>
 +
<tr>
 +
<td> COM1
 +
</td>
 +
<td> /dev/ttyS4
 +
</td>
 +
<td> RS232 2-wire and RS485
 +
</td></tr>
 +
<tr>
 +
<td> COM2(UIO)
 +
</td>
 +
<td> /dev/ttyS7
 +
</td>
 +
<td> RS232 2-wire
 +
</td></tr>
 +
<tr>
 +
<td> COM3(UIO)
 +
</td>
 +
<td> /dev/ttyS8
 +
</td>
 +
<td> RS232 2-wire
 +
</td></tr></table>
 +
<p><b>Note&#160;:&#160;</b>
 +
</p><p>1. Only COM0&#160;and COM1&#160;support RS485 mode.
 +
</p>
 +
<h2> ROM-5880 Borad </h2>
 +
<table border="1" cellpadding="1" cellspacing="1">
  
−
{| border="1" cellpadding="1" cellspacing="1"
+
<tr>
−
|-
+
<td> <b>COM Name</b>
−
| '''COM Name'''
+
</td>
−
| '''Device Node'''
+
<td> <b>Device Node</b>
−
| '''Remark'''
+
</td>
−
|-
+
<td> <b>Remark</b>
−
| COM1
+
</td></tr>
−
| /dev/ttyS4
+
<tr>
−
| support RS232, no flow control
+
<td> COM1
−
|-
+
</td>
−
| COM2
+
<td> /dev/ttyS3
−
| /dev/ttyS7
+
</td>
−
| support RS232, no flow control
+
<td> support RS232,
−
|-
+
</td></tr>
−
| COM3
+
<tr>
−
| /dev/ttyUSB2
+
<td> COM2
−
| support RS232 and RS485
+
</td>
−
|-
+
<td> /dev/ttyS7
−
| COM4
+
</td>
−
| /dev/ttyUSB3
+
<td> support RS232,&#160;no flow control
−
| support RS232&nbsp;and RS485
+
</td></tr>
−
|-
+
<tr>
−
| COM5
+
<td> COM3
−
| /dev/ttyUSB0
+
</td>
−
| support RS232
+
<td> /dev/ttyS4
−
|-
+
</td>
−
| COM6
+
<td> support RS232
−
| /dev/ttyUSB1
+
</td></tr>
−
| support RS232
+
<tr>
−
|}
+
<td> COM4
−
 
+
</td>
−
'''Note&nbsp;:&nbsp;'''
+
<td> /dev/ttyS5
−
 
+
</td>
−
1. Only USB2COM2 and&nbsp;USB2COM3&nbsp;support RS485 mode.
+
<td> support RS232,&#160;no flow control
−
 
+
</td></tr></table>
−
2. COM2 is designed as debug port default.&nbsp;
+
<p><b>Note&#160;:&#160;</b>
−
 
+
</p><p>&#160;
−
== ROM-5880 Borad ==
+
</p>
−
 
 
−
{| border="1" cellpadding="1" cellspacing="1"
 
−
|-
 
−
| '''COM Name'''
 
−
| '''Device Node'''
 
−
| '''Remark'''
 
−
|-
 
−
| COM1
 
−
| /dev/ttyS3
 
−
| support RS232,
 
−
|-
 
−
| COM2
 
−
| /dev/ttyS7
 
−
| support RS232,&nbsp;no flow control
 
−
|-
 
−
| COM3
 
−
| /dev/ttyS4
 
−
| support RS232
 
−
|-
 
−
| COM4
 
−
| /dev/ttyS5
 
−
| support RS232,&nbsp;no flow control
 
−
|}
 
−
 
 
−
'''Note&nbsp;:&nbsp;'''
 
−
 
 
−
&nbsp;
 
  
 
= How to config RS232 or RS485 mode =
 
= How to config RS232 or RS485 mode =

Revision as of 10:33, 19 March 2024

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

RSB-4810 Borad

COM Name Device Node Remark
COM1 /dev/ttyS4 support RS232, no flow control
COM2 /dev/ttyS7 support RS232, no flow control
COM3 /dev/ttyUSB2 support RS232 and RS485
COM4 /dev/ttyUSB3 support RS232 and RS485
COM5 /dev/ttyUSB0 support RS232
COM6 /dev/ttyUSB1 support RS232

Note : 

1. Only USB2COM2 and USB2COM3 support RS485 mode.

2. COM2 is designed as debug port default. 

KEDGE-350 Borad

COM Name Device Node Remark
COM0 /dev/ttyS3 RS232 2-wire and RS485
COM1 /dev/ttyS4 RS232 2-wire and RS485
COM2(UIO) /dev/ttyS7 RS232 2-wire
COM3(UIO) /dev/ttyS8 RS232 2-wire

Note : 

1. Only COM0 and COM1 support RS485 mode.

ROM-5880 Borad

COM Name Device Node Remark
COM1 /dev/ttyS3 support RS232,
COM2 /dev/ttyS7 support RS232, no flow control
COM3 /dev/ttyS4 support RS232
COM4 /dev/ttyS5 support RS232, no flow control

Note : 

 

How to config RS232 or RS485 mode

Enter U-boot interrupt mode

Connect device to debug port, and open debug console. See more : How_to_debug.

Press "ctrl + c" key before power up the device, until get the following information on debug console :  

Hit any key to stop autoboot: 0
=> <INTERRUPT>
=>

Then you can input the following cammand to config UART mode.

Config Uart Mode

Only ttyUSB2 and ttyUSB3 support RS485 mode.

RS485 Mode:  

setenv uart_mode 0x0c
saveenv
reset

RS232 Mode:  

setenv uart_mode 0x00
saveenv
reset

Note : 

The default value is RS232. 

Cp210x support four port, but RSB4810 Only ttyUSB2 and ttyUSB3 support RS485 mode.

Above command "setenv uart_mode 0x0c", 0x0c means set bit2(ttyUSB2) and bit3(ttyUSB3) to 1 (0 means to RS232; 1 means to RS485).

If you just want ttyUSB2 (or ttyUSB3)to be RS485 mode, please change 0x0c to 0x04 (or 0x08).

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