rework rc channel remapping

[Woga65]

Allow remapping of rc channels 1-8 for example TAER1234, AERT2134 or 3AER12T4.
iNavFlight/inav-configurator#1560

[MrD-RC]

To play Devil's advocate. Why would anyone need to remap channels 5-8? These are just mixes in the transmitter.

[Woga65]

To play Devil's advocate. Why would anyone need to remap channels 5-8? These are just mixes in the transmitter.

My personal reasons:

1. For variable pitch aircraft, the throttle-stick is collective pitch, the throttle channel needs to go elsewhere
2. Not all TXes can map this
3. the channel limit was hard coded before, now it respects MAX_MAPPABLE_RX_INPUTS
4. it can be done with Betaflight in the same way
5. it does not hurt

[MrD-RC]

1. For variable pitch aircraft, the throttle-stick is collective pitch, the throttle channel needs to go elsewhere
Surely the collective pitch could go on channel 5? Then throttle would be in the right place. The output that controls the thrust should go on the T channel in the mapping.

2. Not all TXes can map this
I find that hard to believe with modern transmitter.

3. the channel limit was hard coded before, now it respects MAX_MAPPABLE_RX_INPUTS
Nice.

4. it can be done with Betaflight in the same way
Why should iNav copy BetaFlight. There's plenty in their UI that is not great. In fact, I hate that BetaFlight have AETR1234, not AETR5678. Starting the remaining channels from 1 is crap. It is inconsistent with the transmitter.

5. it does not hurt
That's debatable. There is confusion added. For example, I set up my arm switch on channel 5. I set the mapping to AETR6578 (because this is not BetaFlight). Is my arm on channel 6 or 5 after the mapping?

[Woga65]

1. For variable pitch aircraft, the throttle-stick is collective pitch, the throttle channel needs to go elsewhere Surely the collective pitch could go on channel 5? Then throttle would be in the right place. The output that controls the thrust should go on the T channel in the mapping.

2. Not all TXes can map this I find that hard to believe with modern transmitter.

3. the channel limit was hard coded before, now it respects MAX_MAPPABLE_RX_INPUTS Nice.

4. it can be done with Betaflight in the same way Why should iNav copy BetaFlight. There's plenty in their UI that is not great. In fact, I hate that BetaFlight have AETR1234, not AETR5678. Starting the remaining channels from 1 is crap. It is inconsistent with the transmitter.

5. it does not hurt That's debatable. There is confusion added. For example, I set up my arm switch on channel 5. I set the mapping to AETR6578 (because this is not BetaFlight). Is my arm on channel 6 or 5 after the mapping?

1. Graupner: 6 THRO, 7 GYRO GAIN Futaba: 3 THRO, 5 GYRO GAIN Spektrum: 1 THRO, 5 GYRO GAIN,
2. My DX7s and Futaba radio cannot map it. My DeviationTX radio as well as my Zorro can.
3. I agree. Changing it to AETR5678 is trivial and more consistent.
4. CH6 on the radio, CH5 in the modes settings.

[DzikuVx]

I also would like to play the Devil's advocate over here, especially on the CP helis. The throttle has to go whenever it has to go. Throttle is a piece of information for FC of the throttle stick position, not ESC output or CPC output. The main problem is that INAV does not support CP Helis natively and an option to remap does not really help over here at all.

Actually, INAV removed the option of full channel remap a few years ago as it turned out, nobody was using that and it was only causing problems in some of the cases. This was a deliberate choice that as aimed at setup simplification.

The examples that you gave for radios applies only for the case where this radio is used to work directly or via dedicated heli gyro.

If one day INAV will support CP helis, it will support it fully, with all the functions where all the ESC and servos on the heli are plugged in and INAV will handle all the aspects of mixing and motor management.

Let's keep this PR open, maybe reality will change

[Woga65]

I also would like to play the Devil's advocate...

Actually, INAV removed the option of full channel remap a few years ago ... This was a deliberate choice that as aimed at setup simplification.
...
If one day INAV will support CP helis, it will support it fully, with all the functions where all the ESC and servos on the heli are plugged in and INAV will handle all the aspects of mixing and motor management.

Let's keep this PR open, maybe reality will change

Thanks for your thoughts on this topic.
I changed the code to respect MAX_MAPPABLE_RX_INPUTS which is now 4 as it was before.
So if someone likes to change it in the future, it can be done on one single spot in the code.

[CertainBot]

There is one more probable problem, right now the blackbox only logs the first four RC channels, if they are not in the first four channel positions they wont be logged at all.