MKS SKIPR CAN Bus

Okay guys, because I’m so curious, I started taking measurements today and not at the weekend.
Here is what I have found out:

  1. First measurement - CAN-L/CAN-H at CAN-Connector - No signals measurable at the logic analyser!
  2. Second measurement - input pins TXD/RXD at VD1050 CAN Bus Transceiver - No signals measurable!
  3. Third measurement - output pins PB12/13 (CAN2_RX, CAN2_TX) at STM32F407 - No signals measurable!!!

Here are the measuring points on the circuit diagram:



Test conditions:

  • Mellow SHT36 toolhead connected (CAN). Not initialized
  • Klipper connected via built-in USB-CAN-converter. Initialized and running
  • Start of data acquisition on the logic analyzer (7s)
  • UUID-scan on linux to generate traffic on the CAN bus

As expected, the CAN-H line showed a high signal and the CAN-L line a low signal. However, no data was transmitted and no signals could be measured.

My conclusion:

  • Either the issue is on the Klipper Software site

  • or the STM32F446 (Octopus) behaves different to STM32F407 (Skipr)(Klipper driver?)

Other ideas?

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