MCU unable to connect/suddenly no serial connection possible

General Discussion
1

Basic Information:

Printer Model: Qidi X Max 3 Vanilla Klipper 0.12
MCU / Printerboard: MKSPI
Host / SBC
klippy.log

Hello,

my system stopped working after I fiddled around with USB plugs conecting a webcam.

Everything worked great for a long time.
I also ran the updates for all the components this morning.

Klippy.log says that mcu is unable to open serial port: Could not configure port.

I dont understand. Why this error. Everything is connected and shows up in the commandline. The config didn’t change in any way…

Ideas much appreciated! Thank you!

image
image873Ă—395 26.1 KB

image
image992Ă—652 67.2 KB

…
klippy.log (7.0 MB)

2

Klipper does not complain

[mcu MKS_THR]
serial = /dev/serial/by-id/usb-Klipper_rp2040_A5D94D9519ED5658-if00

It complains

[mcu]
serial = /dev/ttyS0
restart_method = command

mcu 'mcu': Starting serial connect
mcu 'mcu': Unable to open serial port: Could not configure port: (5, 'Input/output error')

The issue does not appear at the start of the log. Isn’t the mcu not connected?

BTW: Can’t understand why people install KAMP on Klipper 0.12.0

3

I don’t understand what you ask.
Do you mean if the cable is unplugged or something?

Sorry about KAMP :slight_smile:
Actually I use only the smart park feature and the line purge from it…

4

Edit: All was running fine until I plugged an USB hub to the board. An attempt to utilize more usb ports for camera and such…
After this it didn’t recognize the cam as before and it didn’t work at all with this hub. So I unplugged it and set everything back as before.

I hope I didn’t kill the board or something….

5

Anybody has an idea how to further narrow down error in mcu communication?

6

So, when you remove the USB hub and connect the MCU directly to the host, does that work again?

USB hubs can be quite painful when used with 3D printers.

7

Yes I bet.

So, when you remove the USB hub and connect the MCU directly to the host, does that work again?

No, no of course I removed the device and it’s back to normal now.

But it doesn’t work. I get the mcu communication error after 1 minute where Klipper is reporting „start up“……

8

Can please provide a recent klippy.log

9

klippy (1).log (588.5 KB)

10

I can add a more specific question.
The mainboard MCU is not connecting via serial and I don’t know why.

In the config you have this:

image
image718Ă—368 63.8 KB

When I type: sudo lsof | grep /dev/tty
I see the following:

image
image1355Ă—557 17.4 KB

I tried to use other dev/tty… options available.
No luck.

Any other low level diagnostic approach ?

Btw: I just re-flashed the board with a freshly compiled binary. No luck either.

11

I found this:

So

[mcu]
serial = /dev/ttyS0

is meant to connect via UART.

12

Yes you are correct. It’s connected via UART.

13

What is your comment about?

14

It’s a verification that you connect via UART

15

My problem is not a Klipper topic but apparently rather an armbian problem.

I had to re image the system and set up the same configuration.
Problem gone.

Obviously putting stuff into your USB port can be quite exciting.
In my case the UART connection that ties in the mainboard MCU via /dev/ttyS0 vanished and all efforts to bring it back online where unsuccesful.

Be careful!

1 Like
16

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.