fix: check both SBUS trainer ports regardless of TRAINER_MODULE_SBUS_USART

[raphaelcoeffic]

Fixes #5139

Summary of changes:

• removed #if defined(TRAINER_MODULE_SBUS_USART) and just check presence of potential ports instead.

[mha1]

Thanks

[bug400]

Successfully tested with QX7Acces radio (main and 2.10.1)

[Tiefflieger68]

@pfeerick

I've struggled about an "issue" with my RM MT12.
SBUS Trainer at SPort Pin worked fine at 2.10.1. But with 2.10.2 SBUS input was moved back from SPort Pin to HB Pin.
For my understanding HB should be used if there is no independend SPort Pin in the Module Bay (shared Pin for internal and external Module). But there is a independent SPort Pin in the MT12 Radio. So SPort should be used for SBUS Trainer.

Find the discussion started by me at Discord:
https://discord.com/channels/839849772864503828/839895574244229152/1257669878924705792

[raphaelcoeffic]

For my understanding HB should be used if there is no independend SPort Pin in the Module Bay (shared Pin for internal and external Module). But there is a independent SPort Pin in the MT12 Radio. So SPort should be used for SBUS Trainer.

It's the opposite: S.PORT pin is only used if no heartbeat pin can be used (no hardware serial). It was mistaken in 2.10.1 and has been fixed in 2.10.2.

[Tiefflieger68]

OK - Thanks for clarification

[mha1]

@raphaelcoeffic I have yet to check TX16s 2.10.2. It has a hardware serial on HB but as you know not functional for receiving serial data without a hairy mod. Place your bets if the change killed Master/SBUS on the TX16s.

[3djc]

The HB pin on TX16S does not support inversion, so SPORT pin is used there with 2.10.2

[mha1]

yes, tested, TX16s works with SBUS on SPort.

[Will-Ac]

Using V2.10.4
I have tried to get Master/SBUS feature working on Radiomaster Zorro without luck.
I used a Happymodel EP2 RX connected to module bay.
Before connecting to module bay, EP2 was set to SBUS and confirmed as outputting SBUS using ToolkitRC SBUS input checker, when moving sticks on student (Slave) RM pocket radio.
When I connected EP2 to Instructor radio (Master) module bay, I used a 5V voltage regulator to avoid hurting the EP2, which powered up fine when Master/SBUS was selected as trainer source in model settings and bound to student radio as expected.
I tried connecting the TX pad on EP2 to both the HB and SPORT pins with no luck.
I tried with EP2 set to both SBUS and Inverted SBUS.

I also tried using ToolkitRC SBUS output hooked up to module bay again to both HB and SPORT pins also without luck.

I also tried the above with Pocket and Zorro reversed. No luck.
Has this feature been tested on either Zorro or Pocket?

I do hope I can get it working as it’s a really nice feature and would be great to have it up &running and fully documented.

I tried the wired trainer method and all worked fine as expected.
I also repeated all of the above with Radiomaster ER4 receiver, with working SBUS out, but without success

[Will-Ac]

I have finally figured it out. :)
TLDR: on Zorro, for SBUS in I had to use Module pin PXX IN (EXT_RX) rather than SPORT to get it to work.

It appears that different pins may have to be used on different radios.
To make this feature usable the documentation needs to be updated to clarify which pin on which radio, if they are indeed different. and maybe also whether it requires SBUS or Inverted SBUS isignal in ELRS setup. On my RX I used SBUS.

My working setup is as follows:
EdgeTX V2.10.4 ELRS v3.5
Master setup->
Radio: Zorro internal ELRS
Setup in Module bay (right pin1 - left pin8) ->
Module GND (pin2) VMAIN (pin3) provide 8.4V
Micro BEC steps 8.4V down to 5V. (I will use smallest available being Matek Micro BEC) mine is a bit bigger.
Happymodel EP2 receiver wired to BEC (Max 5V input)
Module PXX IN or EXT_RX (pin6) wired to EP2 TX pad. (I had wrongly tried SPORT and Heartbeat pins, but these might work on other radios) this needs to be better documented
External RF Mode: OFF
Trainer Mode: Master/SBUS
Global functions (or model sepcfic Special functions)->
On push button - Trainer - Axis (or Chans)

Pupil Setup ->
Radio: Pocket internal ELRS
Internal RF - Mode: CRSF (ie ELRS)
Internal module bound to EP2 receiver in Master Radio using different Bind phrase from phrase used between Master radio TX and plane RX

[Will-Ac]

I found same pinout works on RM Pocket.

Here's is my final hardware setup using smaller RX and DC-DC converter, so it fits under module cover.