Micro MinimOSD displays Zeros

So my Micro MinimOSD works perfectly fine until I unplug the battery. When I plug it in again then all the values for batt voltage, etc. are Zero. To get proper readings again I have to log into the MWOSD configurator,
I suspect it’s something related with the serial pass through I am using to get into the MWOSD configurator. When I power cycle, somehow it looks like the FC cannot send data to the OSD…
Any ideas of what could I try next?

Hey Carlos,
Could you provide a wiring-diagram of your setup?
Is your FC plugged into your Computer while you were trying this?

Luca :slight_smile:

Also could you let us know what FC and firmware you are using?

Hi there,

  • As for the wiring, nothing special. OSD wired into UART3, All wired correctly I guess: (+ to +), (GND to GND), (RX to TX) and (TX to RX), plus another GND running from the PDB’s 5V BEC. I soldered but finally cut the wire to the 5V input as it did not seem necessary

  • Computer plugged? I think I have tried every possible combination. Betaflight COM port will not connect unless batt is unpluged. Once Betaflight is connected, batt can be plugged in. To connect to the MWOSD configurator batt must be plugged in because CAM and VTX (and TX) are fed by the batt and not the USB. OSD LEDs do not light unless batt is plugged in too.
    With the computer plugged, after logging into the MWOSD cofigurator, I get the readings right. If I unplug the USB, the readings are still there all right, but TX-RX will not work. (RX is an SBUS plugged into UART2). If I unplug the battery, and plug it in back again, RX works normal, but the OSD (although it is still there) has lost all the data and reads Zeros for all values.

  • As for the setup, I am using a KingKong FPV racer, so I guess the FC should be some version of the SPRacingF3. Firmware is Betaflight 3.3.0 and the FC runs with firmware released on 3/2/2018. I flashed the OSD`s firmware with a USB serial converter and it is running the one version you can download in the mwosd.com website (I think it is R1.7)

Thanks for your help

FC is the KINGKONG F3 Lite 6DOF