Can the LED STRIP pad on an F4 FC be reassigned to function as a UART TX?  I am trying to wire an R-XSR for f.port and it appears to be the only available pin.


I have a Lumenier Micro Lux V3 stack (link to product info page).
It claims to have 3 UARTs (1, 3, and 6) however only 3 and 6 are labelled on the board.  I believe UART 1 is split between SBUS (rx) and LED Strip (tx).  UART 3 is smart audio, and UART 6 is camera control.  

I'd like to wire UART 1 with f.port, and I'm stumped.  I've installed the same hardware on other FC to an actual UART TX pin and it works great, just not this one.  

The R-XSR has been flashed with latest ACCESS f.port firmware, and the X-Lite Pro with updated nightly build and they bind just fine.
I am using the uninverted s.port pad on the receiver.  

The LED Strip resource was originally assigned to A01, it was unassigned and reassigned with serial TX  1 (since f.port requires the tx pin).  Something else was also on A01, I think Sonar something or other.  Anything assigned to A01 has been removed and only Serial TX 1 is there now.

SerialRX_halfduplex has been set to both on and off.  
serialrx_inverted has been set to both on and off.  
serialrx_provider shows correctly as fport.


Am I chasing my tail because this resource cannot be reassigned?  If this is the case, I'll disconnect the camera and use UART 6 or just go back to SBUS and smartport (if the LED Strip pad can be used for smartport).

Or could the LED Strip pad be reassigned to smart audio since it only needs tx?

I suggest you use either TX3 or TX6 for F. Port. Unfortunately, you can't remap a hardware UART to a different pin. You only reassign LED_STRIP to softserial. Anyway, let's get F. Port working and we can discuss camera control and Smartaudio afterwards.

Wire the "P" (hacked non-inverted signal) from R-XSR to TX3 or TX6.

If wire to TX3 use these CLI commands

serial 2 64 115200 57600 0 115200
set serialrx_provider = FPORT
set serialrx_halfduplex = ON
set serialrx_inverted = OFF
Save

If TX6

serial 5 64 115200 57600 0 115200
set serialrx_provider = FPORT
set serialrx_halfduplex = ON
set serialrx_inverted = OFF
Save

Thanks! That confirms my suspicion. I'll rewire it per above and report back.