HOW TO - Connect the serial console

[aivanise]

I've bought a ch340 uart converter from pine shop, it looks exactly like the one on the picture. But when I put the yellow jumper on 3v3, i get nothing in dmesg, only when I put the jumper on 5V I get USB device recognized in dmesg and the ttyUSB port is there, but then,, of course, I don't get anything on it since it is on 5V

This is on 5V
# dmesg | tail -f
[98293.116166] usb 3-1: new full-speed USB device number 3 using uhci_hcd
[98293.304184] usb 3-1: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.54
[98293.304187] usb 3-1: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[98293.304190] usb 3-1: Product: USB2.0-Serial
[98293.307329] ch341 3-1:1.0: ch341-uart converter detected
[98293.314267] usb 3-1: ch341-uart converter now attached to ttyUSB0

this is on 3V3
(...)
nothing, nada, zilch

any ideas? is my ch341 dead? My PC too old?

[a9121431]

Hi all,

Three weeks ago, the RockPro64 kit and serial connector arrived. I tried to run the Debian installer, I could see the console output and failed to enter anything.

I connected the PIN 10 when the installer menu was shown, but the console simply did NOT accept any input.

Any idea what went wrong ?

Thank you,

John

[z3bra]

I've bought a ch340 uart converter from pine shop, it looks exactly like the one on the picture. But when I put the yellow jumper on 3v3, i get nothing in dmesg, only when I put the jumper on 5V I get USB device recognized in dmesg and the ttyUSB port is there, but then,, of course, I don't get anything on it since it is on 5V

This is on 5V
# dmesg | tail -f
[98293.116166] usb 3-1: new full-speed USB device number 3 using uhci_hcd
[98293.304184] usb 3-1: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.54
[98293.304187] usb 3-1: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[98293.304190] usb 3-1: Product: USB2.0-Serial
[98293.307329] ch341 3-1:1.0: ch341-uart converter detected
[98293.314267] usb 3-1: ch341-uart converter now attached to ttyUSB0

this is on 3V3
(...)
nothing, nada, zilch

any ideas? is my ch341 dead? My PC too old?

You're not alone !
I bought one from the store last month, and I have the same issue.
The converter's LED lights up red when I plug it in 3.3V, but dmesg/lsusb remain silent. Tried with Linux kernel versions 5.15.0 (ubuntu 22.04) and 5.15.8 (manually compiled).

So far, I only get messages in dmesg output with 5V mode enabled.

[runyor]

I believe my serial-USB adapter does not support high baud rate as well. This is what I did to change the baud rate on the Debian Installer:

• mount the sd card on your main machine and append this line at the end of /extlinux/extlinux.conf
  APPEND ${cbootargs} console=ttyS2,115200
  
• now you can screen /dev/ttyUSB0whatever 115200
  
• when the ncurses interface started I got gibberish characters (some issue with encoding I guess). To fix that just exit screen (ctrl+a then k then y) and launch screen again. To update the interface I suggest typing (with tx attached of course) something like arrows