Flysky rx on F4 FC using sBus pad.

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Just received a Diatone R349 3" and it doesn't have an option to buy with a receiver.

It does however come with the connector in place for a Frsky R-XSR! So that's nice and easy for Frsky people.
It is connected to the Mamba F405mini stack FC on the pads labelled 0v, 5v and SBUS.



So I would have to use uart6 as uart 3 is used for vtx. So that didn't leave me with any spare uarts and I was thinking of adding a runcam camera control board as I do use that on my Swift Micro v2 on my Martian3.

I was thinking that some FC have a hardware inverter to deal with Frsky's inverted sbus signals and have an un-inverted pad on the same uart. Unfortunately the F405Mini doesn't seem to!
That got me thinking  after a bit of digging, BF 3.3.3 and newer appears that if you select serial rx and then Sbus it automatically inverts the signal. If you select iBus it doesn't invert the signal!! In the CLI it's 'serialrx_inverted' if you want the correct inversion you don't need to do anything!!

Sounded too good to be true. So I used the wires connected to 0v, 5v and sbus to connect to my flit10 rx, selected serial rx on uart1 and iBus. Bingo all working perfectly.
No if only the XSR connector was the same size as the Flit10 I wouldn't have any soldering to do.

So bottom line is would appear that you can use the sbus pad on F4 FC and FlySky rx on iBus will work perfectly on BF 3.3.3 or newer!!!

So I now have the spare uart