Originally Posted by Dennis Frie
It sounds like the OSD is powered from somewhere else. When you turn it off, you say the video kinda fade? Would you mind measuring the voltage between Vcc and a ground-pad (with "faded" video)? It sounds to me like the OSD is powered anyway, but not with the required 5 volt. If a small signal/voltage is available, it might be enough to run Atmega328 but not MAX7456. That will cause Atmega328 to boot without MAX7456 running. That will give the missing overlay. If you continue to have problems just let me know, it should only be a question about a little delay to make sure MAX7456 have started properly before commands are send from Atmega328.
Vcc to Ground is 0.390 V
Connections to OSD are Gnd/Pwr/Signal from the receiver to the "PPM" connections and Vin and Vout from the camera to the VTx. I unplug the power(BEC) from the receiver and get the faded image.
I get the missing overlay with everything powered up. If I power the camera/Vtx first and then receiver/OSD it seems a better chance to get the overlay, but not always.
Would it be better to power the OSD directly with 5V from the BEC rather than through the receiver PPM plug in. My camera/Vtx are 12V. The only connection from the VTx/camera are the Vin/Vout lines.