Basic Information: Printer Model: Highly customized Anycubic Chiron MCU / Printerboard: BTT Manta M8P v2(mcu), BTT EBB42 v1.2 (EBB_X, EBB_Y, EBB_E) Host / SBC: BTT CB2 klippy.log (9.9 MB) The printer is a testbed printer. The hardware and config changes frequently, but the CAN network failur…

This error occurred with single ESB42 with the resistor pins bridged on the end of a straight cable containing 2 twisted pairs of wire. One 18ga the other 14ga. The 14ga are 24v and ground. The 18ga are Tx/Rx. The shielding is grounded at the M8P side only. When I use more than 1 ESB42 the same…

I think I understand the CB2<->M8P connection. It seems the connection is SPI using CAN data protocol but no can transceivers. So data moves as a single sided serial connection electrically, not a double ended can signal. That eliminates the terminating resistors from that branch.

I assume you have read this Lost Communications to mcu A guide for setting up CANBus hardware on 3D printers The fact you occasionally get the error without a toolhead node connected leaves only the connection between the boards, the board traces and solder …

The only problem with a physical connection error is that it requires a full power cycle to reset. To me that feels much more software fault than hardware fault. When I cause a physical connection error a firmware reboot fixes it 100% of the time, as long as the underlying physical connection is f…

[image] Bacheshatonee: MCU ‘mcu’ shutdown: Missed scheduling of next digital out event You may read https://klipper.discourse.group/t/missed-scheduling-of-next-digital-out-event .

@cardoc I ordered an orangePi CM4 to try. I’ve seen a couple other posts and I’m thinking it’s an issue either with BTT’s for of the klipper image or with the CB2 itself.

Because the SPI route is connected “deeper” into the OS than the other method.

@hcet14 I have read through that thread and it’s linked topic. I’ve taken every step I can find to harden/troubleshoot the connections themselves. I do get the occasional retransmits as can be seen in the klipper log. System utilization is low throughout the log, I don’t see anything that appear…

@cardoc Would there be any way to identify if physical faults from traces/connections on the M8P itself are the cause?

CAN network failures - M8P CB2 EBB42

General Discussion

hcet14 August 3, 2025, 10:27pm 16

You may read https://klipper.discourse.group/t/missed-scheduling-of-next-digital-out-event.

Topic		Replies	Views
MCU shutdown: Missed scheduling of next digital out event General Discussion	55	3033	April 14, 2025
Problem with CANBUS during print/idle General Discussion	80	9345	May 7, 2024
USB CAN is down troubleshooting help General Discussion	19	631	January 14, 2025
Chasing Missed digital out event General Discussion	55	761	June 3, 2024
Klipper fails to connect via can, flashing successful General Discussion	10	713	December 4, 2024

CAN network failures - M8P CB2 EBB42

Related topics