Difference between revisions of "How to use UART RK3568"
Yunjin.jiang (talk | contribs) |
Yunjin.jiang (talk | contribs) |
||
| Line 12: | Line 12: | ||
= '''Boards''' = | = '''Boards''' = | ||
| + | |||
== RSB-4810 Borad == | == RSB-4810 Borad == | ||
| − | {| border="1" | + | {| border="1" cellpadding="1" cellspacing="1" |
|- | |- | ||
| '''COM Name''' | | '''COM Name''' | ||
| Line 21: | Line 22: | ||
| '''Remark''' | | '''Remark''' | ||
|- | |- | ||
| − | | COM1 | + | | COM1 |
| − | | /dev/ttyS4 | + | | /dev/ttyS4 |
| − | | support RS232, no flow control | + | | support RS232, no flow control |
|- | |- | ||
| − | | COM2 | + | | COM2 |
| − | | /dev/ttyS7 | + | | /dev/ttyS7 |
| − | | support RS232, no flow control | + | | support RS232, no flow control |
|- | |- | ||
| − | | COM3 | + | | COM3 |
| − | | /dev/ttyUSB2 | + | | /dev/ttyUSB2 |
| − | | support RS232 and RS485 | + | | support RS232 and RS485 |
|- | |- | ||
| COM4 | | COM4 | ||
| − | | /dev/ttyUSB3 | + | | /dev/ttyUSB3 |
| − | | support RS232 and RS485 | + | | support RS232 and RS485 |
|- | |- | ||
| − | | COM5 | + | | COM5 |
| /dev/ttyUSB0 | | /dev/ttyUSB0 | ||
| support RS232 | | support RS232 | ||
|- | |- | ||
| − | | COM6 | + | | COM6 |
| − | | /dev/ttyUSB1 | + | | /dev/ttyUSB1 |
| − | | support RS232 | + | | support RS232 |
|} | |} | ||
| − | |||
'''Note : ''' | '''Note : ''' | ||
| Line 53: | Line 53: | ||
2. COM2 is designed as debug port default. | 2. COM2 is designed as debug port default. | ||
| − | + | == ROM-5880 Borad == | |
| − | + | {| border="1" cellpadding="1" cellspacing="1" | |
| − | + | |- | |
| − | + | | '''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 = | = How to config RS232 or RS485 mode = | ||
Revision as of 10:37, 28 July 2023
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
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.
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).