# FMU \<= MAVSDK =\> NavQ problems **URL:** \ **Category:** MAVSDK\ **Created:** [August 28, 2020, 1:44pm UTC](https://discuss.px4.io/t/fmu-mavsdk-navq-problems/18338 "2020-08-28T13:44:20Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![mdobrea](https://discuss.px4.io/user_avatar/discuss.px4.io/mdobrea/32/7568_2.png) [@mdobrea](https://discuss.px4.io/u/mdobrea)\ **Post date:** [August 28, 2020, 1:44pm UTC](https://discuss.px4.io/t/fmu-mavsdk-navq-problems/18338/1 "2020-08-28T13:44:20Z")
Hi to everyone !!! I want to make a communication between a i.MX 8M Mini SOM (NavQ) and a RDDRONE-FMUK66 flight controller. I installed all the packages, it was fine. When I test without serial cable I get this: ```auto navq@imx8mmnavq:~/MAVSDK/examples/takeoff_land/build$ ./takeoff_and_land serial:///dev/ttymxc2:921600 [04:13:16|Info] MAVSDK version: v0.29.0 (mavsdk_impl.cpp:27) [04:13:16|Debug] New: System ID: 0 Comp ID: 0 (mavsdk_impl.cpp:404) Waiting to discover system... No system found, exiting. ``` When I use the serial cable I get this: ```auto avq@imx8mmnavq:~/MAVSDK/examples/takeoff_land/build$ ./takeoff_and_land serial:///dev/ttymxc2:921600 [04:15:24|Info] MAVSDK version: v0.29.0 (mavsdk_impl.cpp:27) [04:15:24|Debug] New: System ID: 0 Comp ID: 0 (mavsdk_impl.cpp:404) Waiting to discover system... [04:15:24|Debug] Component Autopilot (1) added. (system_impl.cpp:344) [04:15:24|Warn] RTT too high for timesync: 1.59862e+12 ms. (timesync.cpp:90) [04:15:25|Warn] sending again after 0.507136 s, retries to do: 3 (520). (mavlink_commands.cpp:239) [04:15:25|Warn] Command ack 200 not matching our current command: 520 (mavlink_commands.cpp:146) [04:15:25|Warn] RTT too high for timesync: 1.59862e+12 ms. (timesync.cpp:90) [04:15:25|Warn] sending again after 1.01066 s, retries to do: 2 (520). (mavlink_commands.cpp:239) [04:15:25|Warn] Command ack 200 not matching our current command: 520 (mavlink_commands.cpp:146) No system found, exiting. ``` So, something is happening, something is working, but not as I expected. All other parameters are like in the documentation: ```auto MAV_1_CONFIG TELEM2 (the second one on the FMU) MAV_1_FORWARD 0 MAV_1_MODE Onboard MAV_1_RATE 0 ``` on the FMU part the speed of the port is 921600 on the NavQ: `$ stty -F /dev/ttymxc2 921600` Thank you very much! Dobrea Dan. ---
**Author:** ![igalloway](https://discuss.px4.io/user_avatar/discuss.px4.io/igalloway/32/3451_2.png) [@igalloway](https://discuss.px4.io/u/igalloway)\ **Post date:** [August 31, 2020, 8:02pm UTC](https://discuss.px4.io/t/fmu-mavsdk-navq-problems/18338/2 "2020-08-31T20:02:47Z")
I’ll have someone look at this. Hang on… ---
**Author:** ![dk7xe](https://discuss.px4.io/user_avatar/discuss.px4.io/dk7xe/32/5147_2.png) [@dk7xe](https://discuss.px4.io/u/dk7xe)\ **Post date:** [September 1, 2020, 5:02am UTC](https://discuss.px4.io/t/fmu-mavsdk-navq-problems/18338/3 "2020-09-01T05:02:13Z")
i recomment to install mallink-router on the NavQ. With this you can veryfy that the MavLink communication between FMU and NavQ is working. Simply forward the stream via WiFi to a QGC Computer. Instruction is on [https://nxp.gitbook.io/8mmnavq/user-guide/mavlink-specific-details/installing-mavlink-router](https://nxp.gitbook.io/8mmnavq/user-guide/mavlink-specific-details/installing-mavlink-router) After communication is verified add another local port to your mavlink-router config where MavSDK connects to via UDP. ---
**Author:** ![mdobrea](https://discuss.px4.io/user_avatar/discuss.px4.io/mdobrea/32/7568_2.png) [@mdobrea](https://discuss.px4.io/u/mdobrea)\ **Post date:** [September 1, 2020, 8:56am UTC](https://discuss.px4.io/t/fmu-mavsdk-navq-problems/18338/4 "2020-09-01T08:56:49Z")
Hi! A short mention: when I made all the install & tests presented above I was on vacation. Due to limited space I had with me a FMU+power module+GPS module+a telemetry module and, also, a NavQ. Now I am at home with all the equipment, cables & software and now when I connect to the HoverGames it is working perfectly: $ ./takeoff\_and\_land serial:///dev/ttymxc2:921600 [11:35:13|Info] MAVSDK version: v0.29.0 (mavsdk\_impl.cpp:27) [11:35:13|Debug] New: System ID: 0 Comp ID: 0 (mavsdk\_impl.cpp:404) Waiting to discover system… [11:35:13|Debug] Component Autopilot (1) added. (system\_impl.cpp:344) [11:35:13|Debug] Discovered 1 component(s) (UUID: 10832640680271026576) (system\_impl.cpp:517) Discovered system with UUID: 10832640680271026576 Discovered a component with type 1 Vehicle is getting ready to arm Vehicle is getting ready to arm Vehicle is getting ready to arm … or $ ./calibrate serial:///dev/ttymxc2:921600 [11:37:40|Info] MAVSDK version: v0.29.0 (mavsdk\_impl.cpp:27) Waiting to discover system… [11:37:40|Debug] New: System ID: 1 Comp ID: 1 (mavsdk\_impl.cpp:404) [11:37:40|Debug] Component Autopilot (1) added. (system\_impl.cpp:344) [11:37:41|Debug] Discovered 1 component(s) (UUID: 10832640680271026576) (system\_impl.cpp:517) Discovered system with UUID: 10832640680271026576 Calibrating accelerometer… [11:37:41|Debug] MAVLink: info: [cal] calibration started: 2 accel (system\_impl.cpp:250) Progress: 0 … In my opinion some arming preventing mechanism (mainly because I had an incomplete drone) it did not allow the operating system on the drone to launch/configure the internal modules correctly … and hence the problem. Thank you very much for your help and excuse my inconvenience … but I have been struggling for over 4 days and from my point of view everything was OK … and it was OK ;-). Best regards, Dobrea Dan.