Difference between revisions of "How to use UART for RSB-4710"
Xingxing.li (talk | contribs) (Created page with " == '''UART''' == The Android/Linux UART/serial port access is via the tty-devices. The tty-devices have different names depending on the UART driver on different boards...") |
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| Support RS-232 and RS-485 | | Support RS-232 and RS-485 | ||
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== '''How to Configure RS232/485 Mode''' == | == '''How to Configure RS232/485 Mode''' == | ||
Enter U-boot interrupt mode.<br/> Connect the device to the debug port and open the debug console.<br/> Press “ctrl + c” before powering on the device. The following information should be displayed on the debug console: | Enter U-boot interrupt mode.<br/> Connect the device to the debug port and open the debug console.<br/> Press “ctrl + c” before powering on the device. The following information should be displayed on the debug console: | ||
| + | <pre>Hit any key to stop autoboot: 0 | ||
| + | => <INTERRUPT> | ||
| + | =></pre> | ||
| + | |||
| + | Then input the following command to configure the UART mode.<br/> RS-485 Mode: | ||
| + | <pre>setenv uart_mode 0x0c | ||
| + | saveenv | ||
| + | reset</pre> | ||
| + | |||
| + | RS-232 Mode: | ||
| + | <pre>setenv uart_mode 0x00 | ||
| + | saveenv | ||
| + | reset</pre> | ||
| − | | + | Note: <br/> The default value is RS-232. <br/> Cp210x supports four ports, but for RSB-4710 only ttyUSB2 and ttyUSB3 support RS-485 mode.<br/> In the above command “setenv uart_mode 0x0c”, 0x0c means set bit2(ttyUSB2) and bit3(ttyUSB3) to 1 (0 means to RS-232; 1 means to RS-485).<br/> To configure just ttyUSB2 (or ttyUSB3) to RS-485 mode, change 0x0c to 0x04 (or 0x08). |
Latest revision as of 02:59, 25 September 2024
UART
The Android/Linux UART/serial port access is via the tty-devices. The tty-devices have different names depending on the UART driver on different boards.
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 transmit mode. Usually the UART RTS signal is used to switch the
transmitter on and off.
RSB-4710 UART
| Com Name | Device Node | Remark |
| COM1 | /dev/ttyS4 | Support RS-232,no flow control |
| COM2 | /dev/ttyS2 | Debug port |
| COM3 | /dev/ttyUSB0 | Support RS-232 |
| COM4 | /dev/ttyUSB1 | Support RS-232 |
| COM5 | /dev/ttyUSB2 | Support RS-232 and RS-485 |
| COM6 | /dev/ttyUSB3 | Support RS-232 and RS-485 |
How to Configure RS232/485 Mode
Enter U-boot interrupt mode.
Connect the device to the debug port and open the debug console.
Press “ctrl + c” before powering on the device. The following information should be displayed on the debug console:
Hit any key to stop autoboot: 0 => <INTERRUPT> =>
Then input the following command to configure the UART mode.
RS-485 Mode:
setenv uart_mode 0x0c saveenv reset
RS-232 Mode:
setenv uart_mode 0x00 saveenv reset
Note:
The default value is RS-232.
Cp210x supports four ports, but for RSB-4710 only ttyUSB2 and ttyUSB3 support RS-485 mode.
In the above command “setenv uart_mode 0x0c”, 0x0c means set bit2(ttyUSB2) and bit3(ttyUSB3) to 1 (0 means to RS-232; 1 means to RS-485).
To configure just ttyUSB2 (or ttyUSB3) to RS-485 mode, change 0x0c to 0x04 (or 0x08).