MCU ‘EBB’ shutdown: Timer too close

Basic Information:

Printer Model: Heavy modded original Ender 3
MCU / Printerboard: BTT SKR Mini e3 v2 + EBB42 both running over U2C
Host / SBC RPi 4 running RPi OS Bookworm Lite
klippy.log klippy.log (5.8 MB)

Running on fresh RPi image along with Moonsail, both Klipper and Moonsail installed using KIAUH, nothing else was installed on the host. Klipper also has added extensions: KAMP and Bed_Distance_sensor, also the repo might appear dirty due to my gantry calibration script: # in klippy/stepper.py:# change:# for mname in ['stepper_enable', 'force_mov - Pastebin.com, though it’s pretty much force_move wrapper so it shouldn’t cause the error. CAN devices have updated firmware using meteyou guide (I’m limited to 2 links per post so can’t provide a link).

What I’ve found: the error is not caused by bad wiring as it happens every time at the same place in the same gcode file.

What I suspect: I’ve found some “solution” on reddit that this might be caused by variable fan speed setting in slicer. It seems to be working, but it might be pure luck regarding the issue as it happens from time to time, but also IMO it’s not a valid solution but workaround. I’ve tried to increase cycle_time on part cooling fan but it didn’t help while testing it with problematic dirty gcode file.

I can’t really read anything from logs, so any help would be appreciated!

I had issues with Bookworm, dropped back to Bulleye to get things working.

Did you try another g-code model?

I’ll check it out, thanks.

Yes, it doesn’t happen every time, but if it does, it happens in one specific spot of the print.

This type of error, especially with high-frequency fan updates, has nothing to do with the model.

In fact, it is known that some buggy slicer features emit an excessive number of fan updates (multiple updates per second that have no practical meaning), causing this error.
Make sure you are running the latest code, as some precautions have been taken to avoid this issue.

If you can reproduce it with a specific gcode file AND the latest Klipper source, please attach the log along with the gcode file.

I have no issue with Bookworm but generally worth a try. Also use a 32bit Kernel flavor and not the 64bit variant.

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Klipper was installed like 2 weeks ago, was there some commit regarding this since then?

This is one of the files that causes the timer error:
the100-The 100 XLBack_Frame_Bottom_Right_0.25mm_PETG_Generic Klipper Printer_4h24m.gcode (6.5 MB). Compared to successful gcode (with always 100% on fan) it seems to have double the amount of fan updates. Since then I’ve printed pretty much non stop with part cooling fan set to 100%. In the upcoming days I’ll try running some files without filament to check if I can reproduce the problem using 100% fan, non 100% fan with same min / max thresholds and non 100% fan with different thresholds.

I had a look at the G-code. While you find many places like this:

gcode
G1 X135.853 Y75.812 E.3237
M106 S229
G1 X135.853 Y76.512 E.02318
M106 S191
G1 X130.026 Y76.512 E.19298
G1 X129.916 Y76.551 E.00387
G1 X129.853 Y76.685 E.0049
G1 X129.853 Y80.39 E.12271
G1 X129.887 Y80.494 E.00362
G1 X130.026 Y80.563 E.00514
M106 S229
G1 X135.853 Y80.563 E.19298
M106 S191
G1 X135.853 Y81.264 E.02322
G1 X135.853 Y132.812 E1.70721
M106 S229
G1 X135.853 Y133.512 E.02318
M106 S191
G1 X130.026 Y133.512 E.19298
G1 X129.922 Y133.547 E.00363
G1 X129.853 Y133.685 E.00511
G1 X129.853 Y137.39 E.12271
G1 X129.914 Y137.522 E.00482
G1 X130.026 Y137.563 E.00395
M106 S229
G1 X135.853 Y137.563 E.19298
M116 S191
G1 X135.853 Y138.264 E.02322
G1 X135.853 Y143.018 E.15745
M106 S229
G1 F3000

I do not think that this is the root cause for Klipper’s crashing. There are quite a few in the code, but I don’t believe there are enough to cause Klipper to crash. I have seen much worse examples.

The M106 commands are mostly nonsensical, in my opinion, and slicers could really put more effort into producing valid and efficient G-code.

I tried to configure the EBB42 via USB, and after many problems, similar to those you mention, I ended up connecting it via USB… the problems disappeared…

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I’ve printed on 100% fan speed for around 60 hours with fan set to be always 100% and didn’t encountered any problems for now. I suspect that BDSensor’s own code or fan’s software pwm interrupts might cause CAN timing problems? I didn’t look at the MCU side code for now so I probably don’t know what I’m talking about, but considering that there are several topics regarding this issue and considering that BDSensor is not that popular I think it’s worth asking other people that also have timing errors whether it happened with variable / non 100% fan speed to pinpoint whether this might be the cause.

He means that some slicers add a lot of M106 fan control commands in the Gcode output. A high number of unneeded M106 might overload the MCU or be too many to execute to stay in sync.

Note: there is no list of slicers, but the profile might create these due to the cooling or bridging settings.

Hello
I’m having the same problem on SKR Mini v3 on my Creality Ender 3 V2
Alreay, wiped SD card, installed all again, disabled the variable fan speed, etc… Something is consuming Ram from 20% to 99% in few minutos and crashing system.
I have telegram bot installed. Trying to print now with that feature disabled. It must been some update of last versions that is buggy and messing with my system, that was working perfectly.

Why don’t you start a new thread in “General Discussion” and provide all the information (including your klippy.log) requested.

Piggybacking onto somebody else’s thread won’t help you and is a distraction from the issue at hand.

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Hello.
I was just trying to help the user explaining my similar problem. In my case problem was moonraker telegram bot.
After i stopped this service, print was finished.

Cheers