Ultratronics Pro USB connectivity

edited August 2019 in Motherboard
I am completely new to Ultratronics Pro board, just purchased it and installed Repetier Development Firmware from this link https://github.com/repetier/Repetier-Firmware/tree/development

I had no issues compiling and uploading the sketch and I can communicate via programming port USBP (detected as COM4), but when I try to connect via regular USB port, Pronterface shows the following error:

[ERROR] Could not connect to COM3 at baudrate 115200:
Serial error: could not open port 'COM3': WindowsError(5, 'Access is denied.')

Meanwhile Windows detects the port correctly as Arduino Due (COM3). Do I need to change anything in configuration files to activate non-programming USB port? I've tried enabling Bluetooth, since it also uses serial communication, but that did not help.

When connected to Octoprint, I get error "Error: SerialException: 'device reports readiness to read but returned no data". USBP is working fine.



  • Found this thread https://reprap.org/forum/read.php?267,419630 that says

    default is that the firmware uses the programming port and there you can use the normal reset on connect. Only if you modify firmware to use native port instead you need to select "Due Native USB".

    Searched all files and found only 2 config files mentioning Native usb. One is HAL.h file, which contains these lines:
       #ifndef RFSERIAL
           #define RFSERIAL Serial // Programming port of the due
           //#define RFSERIAL SerialUSB  // Native USB Port of the due

    Commented out RFSERIAL Serial and uncommented RFSERIAL SerialUSB definition - it did not help.

    Another file is stacker_3d_superboard.json under boards folder. It contains "native_usb" set to false under Upload section. Changed the value to true and compiled the sketch. No success either. 

    I am starting to question if I even need to use native USB. Is it OK to use programming on Ultratronics for both - programming and regular printing purposes?

  • Both ports are ok to use and have their pros and cons. Programming port resets printer so connecting always works as state is defined. Native port is in theory faster also that speed is not needed, but does not reset on connect. That can cause problems during connect in rare cases until you reset printer.

    Serial error: could not open port 'COM3': WindowsError(5, 'Access is denied.')

    is the strange part. If you see it, it should allow opening port I think. But make sure no other software is connected to that port as windows allows only one software to connect.

    Setting bluetooth to use SerialUSB should in theory allow both ports to use for connection.

    Forget stacker_3d_superboard.json that is a board description for platformio and not used at all fo your board.
  • @Repetier
    Thanks for your reply. I don't have any other software using this port and since Octoprint also fails to communicate, something is probably missing in the configuration.

    I am building brand new IDEX printer of my own design and there are too many other things to learn and work on at the moment. I will probably put this issue on back burner for now and move forward using only programming port.

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