Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
Collapse
Brand Logo

ModalAI Forum

  1. ModalAI Support Forum
  2. VOXL Dev Drones
  3. VOXL m500 Reference Drone
  4. PX4 disconnected from UART & QGC cannot connected to modalAI

PX4 disconnected from UART & QGC cannot connected to modalAI

Scheduled Pinned Locked Moved VOXL m500 Reference Drone
15 Posts 5 Posters 3.0k Views 1 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • H howard

    @DarkKnightCH
    Hi, Please try restarting the voxl-vision-px4 by running systemctl restart voxl-vision-px4.
    Try enabling voxl-mavlink-server
    Also ensure you have right qgc ip address in /etc/modalai/voxl-vision-px4.

    D Offline
    D Offline
    DarkKnightCH
    Contributor
    wrote on last edited by
    #4

    @keil
    Hi, keil, Thanks for help.
    I tried to run the systemctl restart voxl-vision-px4, but it doesn't help.

    What do you mean enabling voxl-mavlink-server?

    QGC ip address is correct.

    1 Reply Last reply
    0
    • D DarkKnightCH

      HI,

      I also found this post which has the same issue with me. I tried to follow the suggestion in this post:I open a MAVLink connection over USB to the flight core, and run mavlink status from the nutshell

      
      NuttShell (NSH)
      nsh> mavlink status
      
      instance #0:
          GCS heartbeat:    267144 us ago
          mavlink chan: #0
          type:        USB CDC
          flow control: OFF
          rates:
            tx: 15.682 kB/s
            txerr: 0.000 kB/s
            tx rate mult: 1.000
            tx rate max: 800000 B/s
            rx: 0.046 kB/s
          FTP enabled: YES, TX enabled: YES
          mode: Config
          MAVLink version: 2
          transport protocol: serial (/dev/ttyACM0 @2000000)
          ping statistics:
            last: 1.72 ms
            mean: 2.18 ms
            max: 6541.72 ms
            min: 0.19 ms
            dropped packets: 5
      
      instance #1:
          mavlink chan: #1
          type:        GENERIC LINK OR RADIO
          flow control: ON
          rates:
            tx: 1.564 kB/s
            txerr: 0.000 kB/s
            tx rate mult: 1.000
            tx rate max: 2880 B/s
            rx: 0.000 kB/s
          FTP enabled: YES, TX enabled: YES
          mode: Normal
          MAVLink version: 1
          transport protocol: serial (/dev/ttyS6 @57600)
      
      instance #2:
          mavlink chan: #2
          type:        GENERIC LINK OR RADIO
          flow control: OFF
          rates:
            tx: 14.672 kB/s
            txerr: 0.000 kB/s
            tx rate mult: 1.000
            tx rate max: 46080 B/s
            rx: 0.000 kB/s
          FTP enabled: YES, TX enabled: YES
          mode: Onboard
          MAVLink version: 2
          transport protocol: serial (/dev/ttyS4 @921600)
      
      instance #3:
          mavlink chan: #3
          type:        GENERIC LINK OR RADIO
          flow control: ON
          rates:
            tx: 1.564 kB/s
            txerr: 0.000 kB/s
            tx rate mult: 1.000
            tx rate max: 2880 B/s
            rx: 0.000 kB/s
          FTP enabled: YES, TX enabled: YES
          mode: Normal
          MAVLink version: 1
          transport protocol: serial (/dev/ttyS1 @57600)
      

      From above information, I cannot track where the issue is, any suggestion?

      D Offline
      D Offline
      DarkKnightCH
      Contributor
      wrote on last edited by
      #5
      This post is deleted!
      1 Reply Last reply
      0
      • D Offline
        D Offline
        DarkKnightCH
        Contributor
        wrote on last edited by DarkKnightCH
        #6

        More tests have done:
        (1) First, I can ssh into voxl through my laptop. And this means the wifi in VOXL is working.
        (2) I can adb into voxl board, which means that my voxl board is not bricked?
        (3)I can connect my flight core with my QGC via USB.
        (4)I tried to run voxl-inspect-services, and it shows
        Screenshot_2022-07-10_16-27-48.png
        (5)I also tried to run voxl-inspect-qvio, and it shows that
        Screenshot_2022-07-10_16-04-32.png

        (6)I also tried to reset the voxl-vision-px4 by running voxl-configure-vision-px4 as follows
        Screenshot_2022-07-10_16-33-19.png

        But there still is a WARNING show PX4 disconnected from UART.

        Any suggestion😧 ?

        1 Reply Last reply
        0
        • Chad SweetC Offline
          Chad SweetC Offline
          Chad Sweet
          ModalAI Team
          wrote on last edited by
          #7

          That warning implies there is an issue in the comms between the Snapdragon and the STM32F7. Maybe try to reload the STM32F7 (Flight Core) firmware and see if that helps?

          1 Reply Last reply
          0
          • D Offline
            D Offline
            DarkKnightCH
            Contributor
            wrote on last edited by DarkKnightCH
            #8

            @Chad-Sweet Yeah. I already reload a flight core firmware and it doesn't help. Is it possible that voxl-vision-px4 server is broken? The UART wire physical connection looks pretty valid. it is hard for me to find out where the issue is from.

            1 Reply Last reply
            0
            • D Offline
              D Offline
              DarkKnightCH
              Contributor
              wrote on last edited by
              #9

              @Chad-Sweet I would like to update my voxl-suite-ipk meta package since I doubt maybe something is wrong about the voxl-vision-px4? is there a simple way to do it except flashing a new system image of voxl? should I use the following command to do it?

              opkg update && opkg upgrade
              
              1 Reply Last reply
              0
              • Chad SweetC Offline
                Chad SweetC Offline
                Chad Sweet
                ModalAI Team
                wrote on last edited by
                #10

                That warning implies a hardware issue more than a software issue. What if you try the nuttx shell to test connectivity between the Snapdragon and Flight Core?

                D 1 Reply Last reply
                0
                • Chad SweetC Chad Sweet

                  That warning implies a hardware issue more than a software issue. What if you try the nuttx shell to test connectivity between the Snapdragon and Flight Core?

                  D Offline
                  D Offline
                  DarkKnightCH
                  Contributor
                  wrote on last edited by
                  #11

                  @Chad-Sweet I tried to follow your advice and it shows

                  voxl:~$ voxl-px4-shell
                  ERROR opening /run/mpa/vvpx4_shell/
                  most likely the voxl-vision-px4 service is not running
                  

                  I also tried to run

                  systemctl restart voxl-vision-px4
                  

                  and

                  voxl-vision-px4 status
                  

                  and it shows

                  voxl:~$ voxl-vision-px4 status
                  loading our own config file
                  =================================================================
                  Parameters as loaded from config file:
                  qgc_ip:                     192.168.0.121
                  en_localhost_mavlink_udp    1
                  en_secondary_qgc:           0
                  secondary_qgc_ip:           192.168.1.214
                  qgc_udp_port_number:        14550
                  localhost_udp_port_number:  14551
                  udp_mtu:                    512
                  en_vio:                     1
                  en_voa:                     1
                  en_send_vio_to_qgc:         0
                  en_send_voa_to_qgc:         0
                  en_set_clock_from_gps:      1
                  en_force_onboard_mav1_mode: 1
                  en_reset_px4_on_error:      1
                  qvio_auto_reset_quality:    0.000500
                  horizon_cal_tolerance:      0.300000
                  voa_upper_bound_m:          1.250000
                  voa_lower_bound_m:          1.250000
                  en_adsb:                    0
                  adsb_uart_bus:              7
                  adsb_uart_baudrate:         57600
                  px4_uart_bus:               5
                  px4_uart_baudrate:          921600
                  offboard_mode:              off
                  follow_tag_id:              0
                  en_tag_fixed_frame:         0
                  fixed_frame_filter_len:     5
                  en_transform_mavlink_pos_setpoints_from_fixed_frame:0
                  =================================================================
                  loading extrinsics config file
                  starting geometry module
                  starting px4 monitor
                  starting uart mavlink
                  Successfully opened mavparser
                  starting udp mavlink
                  Adding manual QGC IP address to udp connection list: 192.168.0.121
                  Added new UDP connection to 192.168.0.121
                  starting px4 shell
                  starting fixed pose input
                  starting vio manager
                  starting tag manager
                  starting voa manager
                  starting control input pipe
                  Init complete, entering main loop
                  Connected to voxl-qvio-server
                  updating to use imu: imu0
                  done updating transforms to use imu: imu0
                  Connected to voxl-tag-detector
                  Connected to voxl-dfs-server
                  WARNING PX4 DISCONNECTED FROM UART
                  

                  any suggestion?

                  1 Reply Last reply
                  0
                  • Chad SweetC Offline
                    Chad SweetC Offline
                    Chad Sweet
                    ModalAI Team
                    wrote on last edited by
                    #12

                    You could try a fresh install by following the instructions here: https://docs.modalai.com/voxl-suite/ . There does seem to be a chance your hardware is damaged though.

                    D 1 Reply Last reply
                    0
                    • Chad SweetC Chad Sweet

                      You could try a fresh install by following the instructions here: https://docs.modalai.com/voxl-suite/ . There does seem to be a chance your hardware is damaged though.

                      D Offline
                      D Offline
                      DarkKnightCH
                      Contributor
                      wrote on last edited by
                      #13

                      @Chad-Sweet Yeah. I tried the following command

                      voxl-configure-opkg
                      

                      and

                      opkg update
                      

                      and then try to restart the voxl-vision-px4 and it seems nothing helps.

                      Since I can connect to voxl through wifi and adb, I have no idea why voxl will broken since I treat it very carefully. Indeed sometimes this QGC disconnection issue happens randomly. Could I mail back the Flight Core and VOXL to you and would you mind helping me check what is the issue?

                      1 Reply Last reply
                      0
                      • A Offline
                        A Offline
                        Anubhav
                        Regular
                        wrote on last edited by
                        #14

                        @DarkKnightCH
                        Hi,
                        Are you able to connect to QGC now. if yes, what was the issue and how you rectified it?
                        Thanks!

                        T 1 Reply Last reply
                        0
                        • A Anubhav

                          @DarkKnightCH
                          Hi,
                          Are you able to connect to QGC now. if yes, what was the issue and how you rectified it?
                          Thanks!

                          T Offline
                          T Offline
                          tpavlic
                          Contributor
                          wrote on last edited by
                          #15

                          @Anubhav and @DarkKnightCH: Was there any movement on this?

                          We have 7 drones with FCv2 (all of our other m500 drones have different FC's) that were also sent to us with the wrong radios. We were able to reconfigure the PX4 for the desired radios (and confirm RC connection to QGC), but running voxl-mavlink-server manually shows a UART error on the console. We are RMA'ing the 7 units with the bad mavlink back to ModalAI for a fix, but it would be great to save the shipping if a fix was found here.

                          1 Reply Last reply
                          0

                          Hello! It looks like you're interested in this conversation, but you don't have an account yet.

                          Getting fed up of having to scroll through the same posts each visit? When you register for an account, you'll always come back to exactly where you were before, and choose to be notified of new replies (either via email, or push notification). You'll also be able to save bookmarks and upvote posts to show your appreciation to other community members.

                          With your input, this post could be even better 💗

                          Register Login
                          Reply
                          • Reply as topic
                          Log in to reply
                          • Oldest to Newest
                          • Newest to Oldest
                          • Most Votes


                          ModalAI
                          Categories Recent Tags ModalAI.com Docs
                          © 2026 ModalAI® · Accelerating autonomy for smaller, smarter, safer drones · Powered by NodeBB
                          • Login

                          • Don't have an account? Register

                          • Login or register to search.
                          • First post
                            Last post
                          0
                          • Categories
                          • Recent
                          • Tags
                          • Popular
                          • Users
                          • Groups