While discussing an upcoming build in   this thread  I came to the conclusion that in order to get one of the plugs to work would require extreme measures. Both my FC and RX have a plug but I want to use FPort and this requires the inversion hack which bypasses the plug and requires the RX to be hard soldered to the FC.

Before starting I updated to the latest FPort FW

As long as I was going to do some very fine soldering to do the inversion hack, I decided to go one step further and route it back to the plug.

First up was to sever the existing Smartport pin. I set the RX up in a little plastic vise and held it in a big vise. I cut a small piece of shim stock to protect the chip right next to the Sport pin





I used a round 1/32" carbide burr and went in and cut the pin in 2



I took  the soldering iron to the bottom half of the pin and pulled it out.  The pin from the plug is now isolated from the RX.



I think the rest of the pics are self explanatory. Note that I left the plug connected during all this to act as a heatsink and provide support for the pin. When I am sure this all works I will put a dab of hot glue behind the plug.





And if some of you guys have never seen the R-XSR before here it is on the tip of my finger, tiny little dude.



This was kind of hard to do with the amount of coffee I had today    I was also wearing 3X readers and my opti-visor , it really is tiny.
I think the only downside to this is it will require soldering a wire back to the Sport pad to update firmware in the future, but now I can unplug it

Scott

Well played sir.

Deal

Great tutorial 

I've been planning to do this on mine for a while but only currently having one R-XSR I didn't want to risk wrecking it and grounding myself, so I always planned to do it whenever I got a second R-XSR (which I still don't yet have).

I was intending to do it the way it was showcased some time ago on RCGroups (HERE and HERE) by cutting the track or removing the resistor, but your way looks just as viable as long as you have an appropriate tool to cut the pin.

I wish FrSky would revise their R-XSR receivers and add a proper non-inverted SmartPort output. They actually do this on their R9MM receivers so maybe they will also start doing this on any other new receivers they manufacture from now on. I guess we shall see.

Thanks Guys !!

My only concern with this approach is that pin is not really connected to anything solid anymore. It could push out of the connector easier than before. That is why I want to put a wad of glue behind it.

Scott

Good job with the tutorial.

If I was going to attempt this mod, I would cut the SBUS IN and jump non-inverted S. Port to that pin. This way, you get your non-inverted signal, get to use the plug, and update firmware without having to resolder things back.

(26-Jan-2019, 05:02 AM)voodoo614 Wrote: If I was going to attempt this mod, I would cut the SBUS IN and jump non-inverted S. Port to that pin. This way, you get your non-inverted signal, get to use the plug, and update firmware without having to resolder things back.

Actually, that's a very good point and something even I hadn't thought about, so thanks for pointing it out. The SBUS IN pin is effectively redudant on a quad build anyway so that is the ideal pin to sacrifice.

I'm not even sure using FC passthrough to flash the receiver would even work because it looks like that still requires flashing to be done through an inverted S.Port pin, although I've not reasearched the possibility in any detail. If not possible then I'm sure successful flashing through an uninverted S.Port pin could be achieved using an Arduino and a bit of creative cutom coding. It shouldn't be rocket science but using the SBUS IN pin instead would save any of those headaches.

(26-Jan-2019, 05:02 AM)voodoo614 Wrote: Good job with the tutorial.

If I was going to attempt this mod, I would cut the SBUS IN and jump non-inverted S. Port to that pin. This way, you get your non-inverted signal, get to use the plug, and update firmware without having to resolder things back.

Yea that would be a really good way to do it......next time.

Scott

(26-Jan-2019, 11:56 AM)SnowLeopardFPV Wrote: Actually, that's a very good point and something even I hadn't thought about, so thanks for pointing it out. The SBUS IN pin is effectively redudant on a quad build anyway so that is the ideal pin to sacrifice.

I'm not even sure using FC passthrough to flash the receiver would even work because it looks like that still requires flashing to be done through an inverted S.Port pin, although I've not reasearched the possibility in any detail. If not possible then I'm sure successful flashing through an uninverted S.Port pin could be achieved using an Arduino and a bit of creative cutom coding. It shouldn't be rocket science but using the SBUS IN pin instead would save any of those headaches.

FC pass through will not work. But, since the receiver can be remove, or at least the plug, you can just plug in the flash cable that comes with every receiver and flash. That is what I meant by not having to resolder.

Hello. Is it possibile to run fport on matek f405ctr without the rx hack?

(03-Feb-2019, 10:03 AM)lorentz Wrote: Hello. Is it possibile to run fport on matek f405ctr without the rx hack?

No, it is not possible. Matek F405 CTR does not have a inverted TX pin. If you are looking for a Matek FC that can do F. Port without hack, I suggest F722 SE.

(03-Feb-2019, 10:03 AM)lorentz Wrote: Hello. Is it possibile to run fport on matek f405ctr without the rx hack?

As per Voodoo's reply.

Inverted SmartPort connected to the SBUS pad will work with F.Port firmware loaded onto the R-XSR as far as all transmitter channel data communications go (meaning you can actually fly the quad), but you won't get any telemetry data back to the transmitter. I found out the hard way by trying it. Even using every permutation of serialrx_halfduplex and serialrx_inverted didn't get telemetry working.

On some flight controllers I'm led to believe that the SBUS pad is bi-directional and you can make use of that without the uninversion hack, but on the Matek F405 that sadly appears not to be the case.

Thanks for the explain. I will stay with the s.port on softserial.

Nicely done!

I have F.Port wired direct from SmartPort pad on my Japalura. It has a Bardwell F4 AIO and an R-XSR RX with no hacks on the TELE pad. This is just UART3 I believe.

I have flight control and telemetry on the single F.Fort wire.

(04-Feb-2019, 02:47 AM)kaitylynn Wrote: I have F.Port wired direct from SmartPort pad on my Japalura.  It has a Bardwell F4 AIO and an R-XSR RX with no hacks on the TELE pad.  This is just UART3 I believe.

I have flight control and telemetry on the single F.Fort wire.

Yes, it works if you have a dedicated SmartPort / TELE pad on the board because those have hardware inversion and are are bi-directional. Unfortunately only a handful of F4 boards seem to have dedicated S.Port/TELE pads on them. If F.Port and TELE pads were something I'd been more aware of when I built my 5" then I would probably have selected a different FC. But that was just down to lack of knowledge and experience at the time