Question about Duet and Smart Stepper wiring
i opened this issue because i think you possibly have the knowledge to give hints about configuring Hangprinter with Duet Board and Misfit Smart Stepper. The thing is that i am working on a mixed thing of different HangPrinter iterations to buildup my own version to do some new experiments (which results i will try to put into community as much as i can from time to time). Initially i saved the money to pay for BLDC motors and ODrives, so i've chosen Smart Steppers and Nema 17 steppers because i was always used to work with regular Steppers and i did not feel comfortable with BLDC.
At the moment my wiring with Duet external pinout (step/dr/en) works fine (see also https://github.com/Misfittech/nano_stepper/issues/40). I also can control the Smart Steppers by USB serial from Raspberry Pi. I recently pushed some Python script to the main repo https://github.com/Misfittech/nano_stepper/issues/54. This works to set Smart stepper in torque mode or to read out encoder position, etc. So it's cool right now.
However, for more advanced configuration like calculting things like you implemented in the firmware using encoder position and spool buildup, i think it would be better to have some direct connection between Duet and Smart Steppers to use the native firmware stuff you worked so hard for. As far as i understand this is not directly possible because Duet has no I2C pinout. I read that the I2C could be theoretically used if Duex extension board is installed but i also read about that I2C is not implemented in RRF right now. :-(
I saw that you connected Odrive with Duet by RX/TX instead on your blog. I am not the serial or electronics pro but my noob question is: Do you see some possibility to wire up four Smart Steppers to Duet in parallel by RX/RX or similar like you did with your "convenience wiring"? I guess the RX/TX can only work with one device or it needs some kind of multiplexing (like I2C or SPI?).
I think a problem of hangprinters in the community is the fact that your fork is really cool but its unmaintained in relation to newer firmware (RRF v3+). Having less custom code would help to easier get the full feature set into the main repo because Dc42 and others say they won't include such heavy modifications. But i also understand that a lot of your work cannot easily be added to the main fork because it's so special. I am trying to build up the printer without modifying more than i need but some features like the encoder readout for Hangprinter calibration seem to be really really useful or maybe totally required. So i am struggling with the problem between general hardware choice, wiring and firmware usage. I try to re-validate my choices to get some steps further and to show up problems, chances, choices and so on.
So happy and glad to get some comments or ideas about that :-)