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Is it possible to use CAN FD in scenario in which there is single main device and additional modules are plugged or hot plugged into each another?

MAIN->MOD1->MOD2->MODn

The main device will have 120ohm termination but how to properly terminate the modules when we do not know how many will be plugged and which is the last one to avoid the stubs?

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  • \$\begingroup\$ The situation is not that different from regular CAN. Your options are basically switching connectors (i.e. they lift a termination resistor when plugged in) or hoping that the customer remembers to fit a terminated stub connector. There are numerous protocols around for dynamic bus setup (e.g. CANOpen). \$\endgroup\$
    – Jon
    Commented Apr 2, 2023 at 10:16
  • \$\begingroup\$ Hardware-wise, you'll either have to move the physical termination resistor to the end of the chain, or otherwise mount it on each node and enable/disable it by for example attaching a wire between two connector pins. Software-wise, there isn't really any problems - except if you hot swap things with supply on, there might be spurious error frames during the swap. \$\endgroup\$
    – Lundin
    Commented Apr 3, 2023 at 14:31
  • \$\begingroup\$ Thanks for the comment. I'm going the way with actively terminating on each end by detecting which module is the last one \$\endgroup\$
    – killdaclick
    Commented Apr 4, 2023 at 15:41

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