I'm facing problem, with ch341 uart chip. ch341 works normally at startup for about 120seconds. After that it disconnects. I'm attaching dmesg bellow.

What it could be a problem? Tried with different healthy cables, connects to Windows PC without any problem...

[  239.257141] ch341 1-1.1.2:1.0: device disconnected
[  246.115361] usb 1-1.1.2: new full-speed USB device number 22 using dwc_otg
[  247.825629] usb 1-1.1.2: device descriptor read/64, error -32
[  248.545744] usb 1-1.1.2: device descriptor read/64, error -32
[  248.765784] usb 1-1.1.2: new full-speed USB device number 23 using dwc_otg
[  248.908772] usb 1-1.1.2: New USB device found, idVendor=1a86, idProduct=7523,                                                                                                   bcdDevice= 2.64
[  248.908780] usb 1-1.1.2: New USB device strings: Mfr=0, Product=2, SerialNumb                                                                                                   er=0
[  248.908785] usb 1-1.1.2: Product: USB Serial
[  248.909508] ch341 1-1.1.2:1.0: ch341-uart converter detected
[  248.912445] usb 1-1.1.2: ch341-uart converter now attached to ttyUSB1
[  253.336684] usb 1-1.1.2: USB disconnect, device number 23
[  253.337088] ch341-uart ttyUSB1: ch341-uart converter now disconnected from tt                                                                                                   yUSB1
[  253.337136] ch341 1-1.1.2:1.0: device disconnected
  • I didn't have problems with a CH340 based converter. Since they are cheap, I would just test a different model, or perhaps your unit is just faulty.
    – 0__
    Jan 7, 2022 at 14:54

1 Answer 1


Check the voltage on your Raspberry Pi. This happens to me when there is a power outage and the Pi is sustained on its miniature UPS. I would also look for lines such as:

[142765.198823] Under-voltage detected! (0x00050005)

It could be that the power supply you are using to power your raspberry pi, is not powerful enough.

  • It was bad PCB tracks and also bad solder connection.
    – douce
    Jun 3, 2022 at 5:24

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