Hey guys,

Really need to enable soft serial on my Furious FPV Kombini DS but I'm a bit lost.  I need this so that I can use Smart Audio as well as and SBUS RX, S.PORT telemetry and OSD.

I thought I had understood that I can find an unused CPU pin, remap that pin to SERIAL_TX 11 and off I go.  Seems like it's not that simple as it's not working for me.

The unused PIN I wanted to hijack for soft serial is the normal SERIAL_RX 2 pin as I only need TX on UART2 (S.PORT telemetry).  I thought I'd correctly identified this as B04 (was mapped to SERIAL_RX 2) so then mapped SERIAL_TX 11 to B04.  My resource output looks like this:



It doesn't seem to work.  Telemetry is working ok, the SBUS RX is also working ok but nothing on SmartAudio.

Hoping someone can give me some guidance here as it's the first time I've gone in to resource mapping or soft serial.  Is it that Iv'e done something wrong with the resource mapping?  I've also seen comments in various github bug posts suggesting some discreet components may be required to use SmartAudio with soft serial but then I've also seen references suggesting this is no longer the case.

Any help appreciated.

Have you enable soft serial in betaflight. What does the Port tab look like after you enable?

I don't think you can remap resource of an used UART if you are already using either the TX or RX.

In general, soft serial usually use one of the PWM pin. Example pin 5 or pin 6. Your FC doesn't seem to have an extra PWM pin.

(28-Sep-2017, 11:28 PM)voodoo614 Wrote: Have you enable soft serial in betaflight.  What does the Port tab look like after you enable?

I don't think you can remap resource of an used UART if you are already either the TX or RX.

In general, soft serial usually use one of the PWM pin.  Example pin 5 or pin 6.  Your FC doesn't seem to have an extra PWM pin.

Soft-serial feature is enabled and on the ports tab I have soft-serial 1 set for SmartAudio.  I tried various speeds and auto but nothing.

I did think it might be too good to be true that I could just re-map the function to any pin that I'm not actively using.  I'd seen a few references to un-mapping PWM5/6 from motor 5/6 so that soft serial can use them but as you say mine appears to have no PWM.  I wonder whether this relates to DSHOT?

Try this. What UART are you using for SBUS? Since, SBUS use an RX, remap that serial 11 to that TX. I think that should work.

Because you were trying to remap a TX to a RX pin, I think that might be the issue.

Thanks that's a good idea, I will see whether or not it works. If not then perhaps I'll just have to scrap this FC and use the spare Betaflight F3 I have.

It would be great if we could attach multiple services to a UART. So as you say SBUS only uses RX and there are other services like SmartAudio or S.PORT that only use TX. We should be able to map TX/RX of each UART independently. Perhaps there's a technical reason why that wouldn't work.

The thing is, both SmartAudio and SmartPort are bidirectional protocols so, any pin that is used for these protocols needs to be capable of switching between being an input and being an output.

A hardware UART has one input pin and one output pin so you can't make a hardware UART's TX pin into a bidirectional port while using the RX pin for an input only serial protocol.

So voodoo's suggestion won't work? If not then I won't waste the time testing it.

Sounds like this FC is ready to scrap then. Real shame, it's been a big disappointment. I thought FuriousFPV were supposed to produce great kit but my experience has been quite different.

You can use the LED pin for soft serial.

Actually, looking a bit closer, you might be able to do it.

Give voodoo's suggestion a try! As this is an F3 board, you won't have to deal with an inverter being in the way and you should be able to re-map the TX pin to soft serial.

Nice suggestion but I want to use the LEDs.

@unseen I saw this too late. Have already ripped out the Kombini and replaced with a spare/backup BF-F3 board I had. This does everything I need and means both of my quads will be identical. I just wanted to use the transponder on the Kombini but with all the hassle it's not worth it; will just get a little transponder I can swap between quads.

Overall the FuriousFPV boards have been a big disappointment. My first Kombini just stopped working after a few weeks (the transponder never worked). They very kindly replaced it with a Kombini DS but as above it still has limitations. No OSD either which most AOI boards have. Seems they are a bit behind the curve with FCs.

It's a general problem as manufacturers try to cram more and more functionality onto smaller and smaller boards. There simply isn't room to run traces for all the UARTs unless they start going to much more expensive six layer PCBs.

Even then, you start to run out of room for solder pads or connectors to connect all the peripherals.

I've noticed that many people seem to have issues with the FuriousFPV boards. In many cases, they are made with very thin circuit boards and particularly when the flight controller is hard mounted or used as a structural component, this causes the internals of the IMU to break in a crash. I had a similar bad experience with the SP Racing F3 Evo.

Unfortunately, your FC doesn't have many spare pads. You can use a non-programmable LED. And use LED pad for soft serial.