Yeah, my old SPRacingF3 drones have add-on MWOSD boards. It was either a board on the back of the Camera, In-between the Camera and VTX, or integrated into the VTX. Most of those have been retired and I no longer fly.
They either have a serial port or USB - serial port built in for configuring the OSD layout using the MWOSD GUI, Minim OSD configurator, etc... depending on what firmware was running on the OSD board. Yet another layer no longer needed with modern hardware. Getting tough to find working copies of some of that firmware and configurators now too.
MWOSD - UAV HUD. Contribute to ShikOfTheRa/scarab-osd development by creating an account on GitHub.
github.com