Hi all,
I am about to start a new build and I want to use the r9m system from FrSky. I have one of the first r9m modules (not the 2019) and a r9mm receiver (not the OTA verison). For Flight controller I am using a Mamba F405. After having a look at the receiver I see the following pads:

* SBUS_Out
* S PORT / F PORT
* GROUND
* V IN
* Inverted S Port

I would like to try Fport as I don´t have much UARTs available and I want to use a GPS also. My question is if "Inverted S Port" pad is also an inverted F Port pad after flashing the corresponding FPORT firmware to the receiver?. If so:

1. does that mean that I can connect the receiver to my FC with just a cable from "Inverted S Port" to TX1 on the FC?
2. is there something I should change in BF to tell the FC that I am using an uninverted FPORT signal?

I hope to be clear enough with my question.

thanks for any advice

Yes you are correct.

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

Change serial 2 to whatever the port number - one. Example serial 2 means port 3.

(02-Dec-2019, 06:58 AM)voodoo614 Wrote: Yes you are correct.

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

Change serial 2 to whatever the port number - one. Example serial 2 means port 3.

Thank you very much voodoo! I find all the information regarding the r9m system very confusing. Between the inverted/uninverted thing and all the drama between Frsky and TBS, there is a lot of misleading information out there, people loving the system and people hating it.
My intention is to build a mid range 7 inch build with GPS. I think I understand the limitations of the r9m, but I just won’t buy Crossfire and I got the r9m combo taking advantage of the last year promotion so why not giving it a chance.
My first idea was to use betaflight, as I am more familiarized with it, but now I am considering trying INAV. Would the serial configuration be the same on inav?

(02-Dec-2019, 02:17 PM)ssombra Wrote: Thank you very much voodoo! I find all the information regarding the r9m system very confusing. Between the inverted/uninverted thing and all the drama between Frsky and TBS, there is a lot of misleading information out there, people loving the system and people hating it.
My intention is to build a mid range 7 inch build with GPS. I think I understand the limitations of the r9m, but I just won’t buy Crossfire and I got the r9m combo taking advantage of the last year promotion so why not giving it a chance.
My first idea was to use betaflight, as I am more familiarized with it, but now I am considering trying INAV. Would the serial configuration be the same on inav?

I am not completely familiar with iNav. But I think it is the same.

If you plan to go to iNav later, I don't think iNav support Mamba F405. If you don't already bought the FC, then consider getting something that is supported by both.

(03-Dec-2019, 02:01 AM)voodoo614 Wrote: I am not completely familiar with iNav. But I think it is the same.

If you plan to go to iNav later, I don't think iNav support Mamba F405. If you don't already bought the FC, then consider getting something that is supported by both.

Everything worked great in Betaflight with your suggestions Voodoo, thanks, I connected the Inverted S Port Pad to TX1 on the FC and used your settings in CLI. Just as information, I also downloaded INAV and it does have the Target for the Mamba F405, I guess that being as attractive from the price / functionality point of view it had a lot of demand and the developers did add the target. I tried it and it also worked, but as I am not familiar with it, I am not sure if I will use it at the end. Anyway, I'll continue with the build but at least the FC - receiver communication works.

Thanks

(03-Dec-2019, 07:08 PM)ssombra Wrote: Everything worked great in Betaflight with your suggestions Voodoo, thanks, I connected the Inverted S Port Pad to TX1 on the FC and used your settings in CLI. Just as information, I also downloaded INAV and it does have the Target for the Mamba F405, I guess that being as attractive from the price / functionality point of view it had a lot of demand and the developers did add the target. I tried it and it also worked, but as I am not familiar with it, I am not sure if I will use it at the end. Anyway, I'll continue with the build but at least the FC - receiver communication works.

Thanks

Very good.