Arduplane SpeedyBee RSSI (Analog) Not Working

Hi there - I’ve been working to get RSSI via analog working on my SpeedyBee F405 Wing and no matter what I try, I can’t get it to show up. Receiver is R9M OTA + and I’m using a SpeedyBee F405 Wing. I’ve routed the analog RSSI output from the receiver (checked w/ multimeter to verify its supplying voltage) to the RSSI pad on the FC. In ArduPlane, I’ve set it to analog pin and have tried every serial source available in the settings with zero results. Low voltage set to zero and high set to 3.3v.

I’m not sure what I’m missing here - it seems pretty straightforward and simple, yet I’m not getting a good result. Any help is appreciated.