V0 Display High Load, then disconnecting.

[Ingold]

Printer Model

V0.2

Extruder Type

Other

Cooling Type

Other

I have a weird problem with the V0 Display Board. It worked fine for over 2 months of printing (roughly 30 hours of total print time according to Mainsail), and then it started timing out and I got the MCU Display timeout error. I upgraded the firmware to v0.11.0-235 before I started my first print. I did some more testing and noticed the Load on the Board maxed at 100%, it would stay like that until it timed out. I have disconnected it from the USB port, so that I can keep printing but would like to find a solution.

Has anyone seen this behaviour with STM32F042-based boards?

 

[Jon]

The 100% load is normal and should not cause any concerns. The timeout/disconnect is though. Could you grab a log of when it happens?
Also, how did you route the cable? The psu is emitting alot of noise, which I've found the usb cable to dislike, so avoiding crossing mains could be another thing to check. And lastly, are you using the usb plug or the 4 pins in the back of the display? It could just be bad connection too.

 

[Ingold]

The 100% load is normal and should not cause any concerns. The timeout/disconnect is though. Could you grab a log of when it happens?
Also, how did you route the cable? The psu is emitting alot of noise, which I've found the usb cable to dislike, so avoiding crossing mains could be another thing to check. And lastly, are you using the usb plug or the 4 pins in the back of the display? It could just be bad connection too.

Its a 4PIN at the back type board, which I now want to be a micro-USB because I could easily use another USB cable.

I triggered the shutdown by running a heatsoak for 20 min, then kicking off a long print. It didn't even make it to the purge line.

This is as much useful info I can get:
Mainsail Message

Lost communication with MCU 'display'
Once the underlying issue is corrected, use the

dmesg

[   47.490769] usb 6-1: SerialNumber: 2E003C001547323330373434
[   47.493208] cdc_acm 6-1:1.0: ttyACM0: USB ACM device
[19839.088131] usb usb7-port1: disabled by hub (EMI?), re-enabling...
[19839.088165] usb 7-1: USB disconnect, device number 2
[19839.442154] usb 7-1: new full-speed USB device number 3 using ohci-platform
[19839.677290] usb 7-1: New USB device found, idVendor=1d50, idProduct=614e, bcdDevice= 1.00
[19839.677311] usb 7-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[19839.677319] usb 7-1: Product: stm32f042x6
[19839.677325] usb 7-1: Manufacturer: Klipper
[19839.677332] usb 7-1: SerialNumber: 2300240017434E5532373620
[19839.683363] cdc_acm 7-1:1.0: ttyACM2: USB ACM device

Klippy.log

Timeout with MCU 'display' (eventtime=19843.474916)
Transition to shutdown state: Lost communication with MCU 'display'
Dumping gcode input 0 blocks

There is a lot there, but it doesn't give me any hints outside the device disconnects and reconnects to the HUB, which then causes Klipper to freak out and shut down.

Cable Routing attached. I will change it to the bottom of the power supply, and test again.

 

[chirpy]

The 100% load on the display is normal, it's constantly polling for input. I checked through previous reports that I could find. There aren't many, but I found one with a hub where the hub seemed to be the problem, all the others were bad USB cables.

 

[Ingold]

The 100% load on the display is normal, it's constantly polling for input. I checked through previous reports that I could find. There aren't many, but I found one with a hub where the hub seemed to be the problem, all the others were bad USB cables.

I found the same, except for the hub. All others point to the cable; I disregarded them because the display has been working fine for over 30 hours of printing, and if it were a faulty cable, it would also error out while idle. If it was the hub, then the other USB device (WiFi module) would also error out with usage, and I am not seeing that.

I think interference is the source of the problems, I have shifted the cable and have done three long prints after heat soak, and it hasn't failed yet. I also added a 90° USB connector so the original cable USB A connector not Bending against the enclosure panel.

I will continue to do more printing and see if it fails.

 

[Muffinman]

Any movement on this? Mine is doing the exact same thing. If I move screen menu to something other than the print screen the load goes to 1% and the print will finish with out any issues.

 

[Ingold]

Any movement on this? Mine is doing the exact same thing. If I move screen menu to something other than the print screen the load goes to 1% and the print will finish with out any issues.

Mine still does it, I got fed up and disconnected my display.

 

[Muffinman]

Well that is a bummer... I will keep working on it and see what I can come up with.

 

[ChrisA]

Its a 4PIN at the back type board, which I now want to be a micro-USB because I could easily use another USB cable.

I looked at the photo. That is not even a "real" USB cable. It is just a common four-conductor cable. I'd expect trouble. A "real" cable will have the data + and data - wires twisted and a shield around the cable. The power wires need not and should not be twisted. Buy a correct-length, high-quality cable and a real connector, not the DuPont pins

USB runs at the megaHertz clock rates. It is basically "radio in a wire" and you have to treat the cables as such

 

[Ingold]

I looked at the photo. That is not even a "real" USB cable. It is just a common four-conductor cable. I'd expect trouble. A "real" cable will have the data + and data - wires twisted and a shield around the cable. The power wires need not and should not be twisted. Buy a correct-length, high-quality cable and a real connector, not the DuPont pins

USB runs at the megaHertz clock rates. It is basically "radio in a wire" and you have to treat the cables as such

Thanks for that. It makes a lot of sense; essentially, I need to buy a new board with an actual USB connection and throw that one out or break it down for parts.

 

[ChrisA]

Thanks for that. It makes a lot of sense; essentially, I need to buy a new board with an actual USB connection and throw that one out or break it down for parts.

Or buy a 4 cent USB connector and solder it on. They are really cheap. It is. common repair item too so they sell them in kits

https://www.aliexpress.us/item/3256805418705181.html?spm=a2g0o.productlist.main.1.7e7867a5Juebkl&algo_pvid=4e9d57ef-a81b-44e5-9cc4-7a36e9cbacb0&algo_exp_id=4e9d57ef-a81b-44e5-9cc4-7a36e9cbacb0-0&pdp_npi=4%40dis%21USD%216.66%211.93%21%21%2147.65%2113.82%21%402103010c17072907542751949e2137%2112000033783940030%21sea%21US%21136631752%21&curPageLogUid=FMfQzSv7FwfX&utparam-url=scene%3Asearch%7Cquery_from%3A

 

[Ingold]

Or buy a 4 cent USB connector and solder it on. They are really cheap. It is. common repair item too so they sell them in kits

https://www.aliexpress.us/item/3256805418705181.html?spm=a2g0o.productlist.main.1.7e7867a5Juebkl&algo_pvid=4e9d57ef-a81b-44e5-9cc4-7a36e9cbacb0&algo_exp_id=4e9d57ef-a81b-44e5-9cc4-7a36e9cbacb0-0&pdp_npi=4%40dis%21USD%216.66%211.93%21%21%2147.65%2113.82%21%402103010c17072907542751949e2137%2112000033783940030%21sea%21US%21136631752%21&curPageLogUid=FMfQzSv7FwfX&utparam-url=scene%3Asearch%7Cquery_from%3A

Thanks for the info, and the link. I am not 100% sure about the wiring but I am sure I can work it out, with some googling and a continuity testing.