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    connect with usb to COM-NB-IOT-MODULESIM7020G fails

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    usb driver sim7020g teminal
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    • O
      olavk
      last edited by

      Hi,
      I cant get the USB port on sim7020g modem working. I just connect my PC with a terminal emulator.
      The board powers up (red led) and blinking blue NET LED.
      However I only get garbage characters on my terminal as if the speed was wrong.
      I have tried all speeds without success. Default is 115200 8N1.

      It generates 2 USB-devices as other modems like SARA R410 do.
      Should it be possible - any clues ?

      Olav

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      • felmueF
        felmue
        last edited by

        Hello @olavk

        I assume you mean the USB port on the green board plugged into the COMX.NB-IoT module, correct?

        If yes, then according to the SIM7020G Hardware Design Guide - chapter: 1.4 Functional Overview the USB port is meant for debugging. Maybe that means it cannot be used to issue AT commands?

        Thanks
        Felix

        GPIO translation table M5Stack / M5Core2
        Information about various M5Stack products.
        Code examples

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        • O
          olavk
          last edited by

          Thanks @felmue - Yes I mean the USB on the breakout board. The referred manual states : 'The SIM7020G contains a USB interface compliant with the USB1.1 specification as a peripheral'.
          And my intention was indeed to do debugging to see if the modem would connect to the network with my SIM before I start to connect it to my Arduino.

          Anyone that have a connection diagram for how to connect this breakout-board to an Arduino (MKR Zero),
          as I don't want to use the M5 Stack wrapping.

          So I have pins PWR, GND and P/G on one side and VIN VEXT and VTTL on the other side.
          Could I expect P/G to be the pin to trigger to power on/off ?

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          • felmueF
            felmue
            last edited by

            Hello @olavk

            no, I don't think P/G is the on/off trigger. It seems to be connected to GND. I think PWK is the power key.

            Have a look at the COMX schematic. You'll find this:

            • P/G : is connected to GND

            • GND : is connected to GND

            • PWK : is connected to EN

            • RXD : is connected to GPIO17, GPIO0 or GPIO17

            • TXD : is connected to GPIO16, GPIO5 or GPIO15

            • VIN : is connected to either 5.4 V or whatever is provided at the DC in

            • VIN : dito

            • VTTL : not connected

            • VEXT : not connected

            How exactly this translates to an Arduino MKR Zero I cannot tell. I don't have one to try. Sorry.

            Thanks
            Felix

            GPIO translation table M5Stack / M5Core2
            Information about various M5Stack products.
            Code examples

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            • O
              olavk @felmue
              last edited by olavk

              Thanks @felmue,
              I have now got the card powered by following your observations :
              connecting 5v to VIN, GND to GND, TX to RXD, RX to TXD
              I don't need to trigger PWK to get the modem operational.
              The modem don't connect to the network, but that's another problem..

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