I'm building my first FPV and experiencing some issues connecting my radio to FC.

Some words about my setup:
FC: Darwinfpv 15A 1-3S F411 Ultralight/Whoop AIO https://darwinfpv.com/products/darwinfpv...8399501487 
Radio: Jumper T-Lite V2 ELRS
Receiver: ELRS Mini https://www.aliexpress.com/item/10050059...caa4tNMyNw

• I soldered everything. rx -> tx, tx -> rx.
  
• Flashed latest Betaflight (4.4.3) to FC. Here I had issues initially. Official FC website says "BetaFlight target: MATEKF411". When I flashed it for that target I got no gyro, no accel, no motors control, maybe some other unidentified issues. When I flashed for target DARWINF411 I started seeing gyro, accel and could control motors. Everything (?) works fine now.
  
• Flashed latest EdgeTX (2.9.4) and ELRS (3.3.2) to radio.
  
• Flashed latest ELRS (3.3.2) to RX. Used all recommended options and custom binding phrase equivalent to radio firmware.
  
• I bound radio with receiver. I may say it's successful. When I power up both led on the receiver goes solid and also I may switch it to wi-fi mode from the radio.
  
• In BetaFlight I have the following config:
  Ports -> UART1 -> SerialReceiver -> Receiver mode = Serial (via UART)Receiver -> Serial Receiver Provider = CRSFReceiver -> Telemetry = onReceiver -> RSSI_ADC = offReceiver -> RSSI channel = disabled
  

But... I don't receive any input from the radio in the Betaflight's "Receiver" tab. I went through all official setup checklists, troubleshooting pages, google requests and still no luck here. What can I do else? Is there any way to check where's the issue: receiver, FC, firmware, config? Is it something with hardware or software?

Your settings and connections look to be correct. Did you turn off model match? Go into the LUA script, turn it on, save it, then turn it off again. Sometimes there is a problem with that.

(01-Mar-2024, 11:27 PM)mstc Wrote: Your settings and connections look to be correct. Did you turn off model match? Go into the LUA script, turn it on, save it, then turn it off again. Sometimes there is a problem with that.

Model match is off. I tried to turn it on and off again, it didn't help.

Hmmm... UART1 also has SBUS, sometimes there is a problem with the pulldown resistor putting the ELRS RX into boot mode. If you turn OFF your radio, and the ELRS RX light is still solid, then that is a good indication of that problem. Probably the easiest is to move it to UART2 instead.

https://www.expresslrs.org/quick-start/r...wiring-up/

Holy cow.
I accomplished my mission. It was really tricky.

Given wiring instruction has the following tip and hint.

Quote:Hot Tip
Manufacturer-suggested Receiver UARTs, or UARTs alloted for Receivers usually have a pull-down resistor to aid with SBUS (RX pad inversion) which will result into SOLID LEDs on the ESP-based ExpressLRS Receivers. It is best to avoid those UARTs unless you know your UARTs.

Hint!
KISS FCs may label its UARTs differently. You might have to wire up the RX pin into an RX pad, and the TX pin into a TX pad. Always check your FC wiring guide/manual.

I had to follow both.
I soldered receiver to UART2 as [RX-RX, TX-TX] and it works now. I tried that trick as a wild guess on UART1 before, but it didn't help me.