I use the F405-wing FC(firmwaire arduplane_with_bl4.1.7.hex),and use the serial 1 to connect the elrs nano recevicer. And I’m sure the hardware connect is correct.
Ardupilot setup like this: Uploading: 2.jpg…
I measured the FC’s serial1 with the oscilloscope. The RXD had the signals ,but the txd whitout any signals. So I think maybe the parameters I set are worng.
RC_PROTOCOLS can just be “1”. (Incidentally, 513 is 1+512 so you’ve already enabled all the protocols.) Or you could try it with just 512.
RSSI_TYPE should be 3. And you might want to enable bits 8 and 9 in RC_OPTIONS.
Does the radio configuration page in mission planner show movement when you move the TX sticks? Are you sure the TX is set up properly (do you have other ELRS models that it works with)?