It’s that thorny old problem that so many pilots have trouble with - getting RSSI to work!
So, I have a Pixhawk PX4 and FrSky X8R Rx and Taranis X9D Plus Tx.
This is what I have done so far:-
The X8R RSSI is connected to the PX4 SBUS out port. In the following configuration I have tried using a normal servo lead, and one I modified with an RC network.
In Mission Planner 1.3.41 APMCopter V3.3.3
RSSI_PIN 103 (no options for this)
BRD_SBUS_OUT (3 options for frame rate: 50Hz, 75Hz & 100Hz, all tried with no success).
I re-booted the PX4 after every change.
I cannot obtain any RSSI output. I have measured the voltage output of the X8R when connected to the PX4; with the Tx on it measures 3.19V max, Tx off it measures approx 40mV. Clearly, the X8R is outputting RSSI values.
The MinimOSD (connected to Telem 1) always shows 0% RSSI. I also ran QGroundControl v2.9.4, which has an RC RSSI facility; this too always shows 0%. It appears then, that the Telem 1 port is not outputting RSSI data.
Is there something I have missed, or is there a fault in the PX4?
Assistance with this would be hugely appreciated. Thanks in advance.