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    CAN-FD hardware

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    • JoergS5undefined
      JoergS5
      last edited by JoergS5

      I want to experiment with CAN-FD: is it possible to use it to transmit data e.g. for quality control by cameras. I want to build it with hardware which is compatible with Duet 3.

      So far I found some MCP25...FD chips, with the dual CAN-FD MCP25612FD the most interesting (about 5$). Is there experience whether they are compatible with Duet 3, or, if not, is there good hardware for this purpose?

      The new Teensy 4 has CAN-FD also, is this compatible with Duet 3?

      Addition: TCAN4550 seems very promising, it is controller and transceiver and only about 3$.

      dc42undefined 1 Reply Last reply Reply Quote 0
      • dc42undefined
        dc42 administrators @JoergS5
        last edited by

        We use the MCP2542 chips for driving the CAN bus. They have a separate power pin for the MCU interface, so they can level shift between a 3.3V MCU and still use 5V to drive the CAN bus.

        Duet WiFi hardware designer and firmware engineer
        Please do not ask me for Duet support via PM or email, use the forum
        http://www.escher3d.com, https://miscsolutions.wordpress.com

        JoergS5undefined 1 Reply Last reply Reply Quote 0
        • Kulitorumundefined
          Kulitorum
          last edited by

          What is the max cable length for the CAN-FD Bus?

          Kulitorum

          JoergS5undefined 1 Reply Last reply Reply Quote 0
          • JoergS5undefined
            JoergS5 @dc42
            last edited by

            @dc42 Thank you. I hope the MCP25 family is compatible with each other. If not, I will let you know...

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            • JoergS5undefined
              JoergS5 @Kulitorum
              last edited by JoergS5

              @Kulitorum According to the table in https://www.computer-solutions.co.uk/info/Embedded_tutorials/can_tutorial.htm it is 10 m (ISO 11898-2 2015). Small house 😉

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              • dc42undefined
                dc42 administrators
                last edited by dc42

                Max cable length depends on the data rate and the number of devices on the bus. We use 1Mbits/sec as the base data rate. Page 5 of http://www.ti.com/lit/an/slla270/slla270.pdf suggests 1Mbits/sec should be OK to 40m length. The fast data rate will be configurable, https://duet3d.dozuki.com/Wiki/Gcode#Section_M952_Set_CAN_FD_bus_data_rate.

                Duet WiFi hardware designer and firmware engineer
                Please do not ask me for Duet support via PM or email, use the forum
                http://www.escher3d.com, https://miscsolutions.wordpress.com

                T3P3Tonyundefined 1 Reply Last reply Reply Quote 0
                • T3P3Tonyundefined
                  T3P3Tony administrators @dc42
                  last edited by

                  @Kulitorum 40m.. slighly larger house 😄

                  www.duet3d.com

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                  • Kulitorumundefined
                    Kulitorum
                    last edited by

                    I was hoping for 150m 🙂

                    Will everything work at 0.25Mbps?

                    Kulitorum

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                    • dc42undefined
                      dc42 administrators
                      last edited by

                      Currently it would need a new firmware build to change the base data rate, because everything (including the bootloaders on the expansion boards) needs to know what that data rate is. Using lower speeds might work if the machine isn't tool complex and doesn't print sequences of tiny segments fast, so that we don't need to send movement commands to expansion boards at too great a rate.

                      Duet WiFi hardware designer and firmware engineer
                      Please do not ask me for Duet support via PM or email, use the forum
                      http://www.escher3d.com, https://miscsolutions.wordpress.com

                      1 Reply Last reply Reply Quote 0
                      • Kulitorumundefined
                        Kulitorum
                        last edited by

                        hehe, shame.

                        I print 1000mm/sec with vertices for every 5mm...

                        So can I amplify the signal every 40 meters? - Do expansion boards daisy chain?

                        T3P3Tonyundefined 1 Reply Last reply Reply Quote 0
                        • JoergS5undefined
                          JoergS5
                          last edited by JoergS5

                          I saw there exist CAN-FD repeaters, maybe an option.

                          It exists a CAN FD repeater reference design by http://www.ti.com/lit/ug/tidudb5a/tidudb5a.pdf (for an optional extension card maybe).

                          Kulitorumundefined 1 Reply Last reply Reply Quote 0
                          • T3P3Tonyundefined
                            T3P3Tony administrators @Kulitorum
                            last edited by

                            @Kulitorum said in CAN-FD hardware:

                            Do expansion boards daisy chain?

                            yes, but only physically, they don't amplify/act as an active repeater.

                            www.duet3d.com

                            1 Reply Last reply Reply Quote 0
                            • Kulitorumundefined
                              Kulitorum @JoergS5
                              last edited by

                              @JoergS5 Thanks, looks good.

                              1 Reply Last reply Reply Quote 0
                              • Kulitorumundefined
                                Kulitorum
                                last edited by

                                Once I receive the expansion boards, I will experiment with this. Any ETA?

                                T3P3Tonyundefined 1 Reply Last reply Reply Quote 0
                                • T3P3Tonyundefined
                                  T3P3Tony administrators @Kulitorum
                                  last edited by

                                  @Kulitorum will be emailing those who expressed an interest in the prototype boards after TCT show next week (you are on the list!)

                                  www.duet3d.com

                                  1 Reply Last reply Reply Quote 0
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