Issues with CAN bus

[EddyMI3D]

Honestly, it’s never a good idea to use items for different specifications.
USB cables are for USB protocol.

I already saw someone who suggested to use USB cables and connectors for microphones.

[DrumClock]

@mykepredko

My question is: at what point will you accept that your approach is wrong?

Well, they used USB connectors for easy connection.
I know it is not a standard for CAN bus.

What if I create a twist pair of wires and put a USB-A and USB-C connector on the ends, it will already be a CAN line according to the specification.

The question is will it work when there is in the way USBLC6-2SC6 ?

Note:
By the way, U2C is the same “Chinese shit” as their CB1 or MANTA.
The last thing that is really good from BigTreeTech is Octopus and EBB.

And this concludes this discussion.
** Have a great time everyone.**

[hcet14]

@TheFuzzyGiggler

https://www.mikrocontroller.net/attachment/28831/siemens_AP2921.pdf
No wonder people have issues with BTT boards and CAN Bus in all the forums.

I know and read that document, hopefully understood it

That’s why CAN-FD was introduced by Bosch.
marckleinebudde is maintaining this branch GitHub - marckleinebudde/candleLight_fw at multichannel
I think it’s working properly on STM devices used on toolheads for 3D printers running Klipper. My hope is the CAN-FD protocol will be used in the future by Klipper.
candleLight_fw is already used!

[EddyMI3D]

@DrumClock

What if I create a twist pair of wires and put a USB-A and USB-C connector on the ends, it will already be a CAN line according to the specification.

I think you better run with RJ45 plugs and cables.

[hcet14]

@koconnor

You definitely do not want to run CAN RX/TX over long lines. It is definitely not valid to wire multiple devices to the same CAN RX/TX wires (these wires are not a “bus” - they are only point-to-point and intended for short distances).

Do I understand that right? Klipper supports just a 2 node CAN bus?

CAN topology usually looks like

Kind regards, hcet14

[koconnor]

@hcet14

@koconnor

You definitely do not want to run CAN RX/TX over long lines. It is definitely not valid to wire multiple devices to the same CAN RX/TX wires (these wires are not a “bus” - they are only point-to-point and intended for short distances).

Do I understand that right? Klipper supports just a 2 node CAN bus?

CAN_RX/TX are a pair of short wires between micro-controller and canbus transceiver chips. CAN_H/L are a pair of wires that form a bus after the canbus transceiver chip. That bus can have many devices on it and can be quite long (100 or so meters). Klipper, of course, supports many devices and long wires on a functional CAN bus (CAN_H/L).

Running long CAN_RX/TX wires is not at all recommended. Placing multiple devices on the same low-level CAN_RX/TX lines is not valid. If you look closely at the schematics posted above it could route the CAN_RX/TX wires off the local board (not a good idea) and could share multiple devices on the same CAN_RX/TX wires (the local transceiver and the remote mcu – definitely not going to be stable).

I feel this conversation seems to be devolving from silly to absurd.

-Kevin