feat: S.Port telemetry for PPM/SBUS external module

[raphaelcoeffic]

Fixes #5064

Summary of changes:

• add S.PORT telemetry to PPM external modules
• add S.PORT telemetry to SBUS external modules

[mha1]

needs Companion update too

[raphaelcoeffic]

needs Companion update too

Right, may I ask for some good soul to take care of companion please?

[mha1]

Right, may I ask for some good soul to take care of companion please?

Don't know about the good soul: #5691

And there's one odd thing. CPN thinks SBUS is presented at VBat. That can't be true right? Let me know then I'll change it to plain "SBUS".

[raphaelcoeffic]

Frankly, I have no clue why the label says "SBUS output at VBat". @3djc @elecpower any clue why?

[3djc]

I guess that might be true for frsky radio? (Don't have any to check)

[mha1]

OpenTX implemented SBUS out on JR bay twith this PR: opentx/opentx#5225. A screenshot found in this PR hints to how SBUS output at VBat needs to be understood. It's a warning SBUS levels are at battery voltage. Are there really radios doing this?

[mha1]

2.11 EdgeTX still warns all(!) b&w users that SBUS outputs current radio battery voltage levels. Color LCD users are warned levels are 5V. The wacky world of FrSky radios.

This is a screenshot from a T12max, SBUS@CPPM pin. The T12 outputs SBUS at 3.3V levels, yet the user is warned it's Vbat levels. The warning is if any only valid for some radios. The warning should be selective.

        else if (isModuleSBUS(moduleIdx)) {
          lcdDrawTextIndented(y, STR_WARN_BATTVOLTAGE);
          putsVolts(lcdLastRightPos, y, getBatteryVoltage(), attr | PREC2 | LEFT);

[Target0815]

The warning is false. It was once introduced because SBUS was originally issued on VBat, which is no longer the case.

[mha1]

The warning is false. It was once introduced because SBUS was originally issued on VBat, which is no longer the case.

@pfeerick @3djc @raphaelcoeffic If this is true (looks like it) the warnings should be removed (b&w, color radio and CPN). Your thoughts?

[raphaelcoeffic]

AFAIK, there are still a few old radios doing it (not sure which), but yes, it is probably too much to scare everyone for something that is not really the case anymore.

I don't think however this is related to the issue at hand.

[mha1]

I don't think however this is related to the issue at hand.

Sure, I just noticed and it really looks odd. I mean you're right this is not directly related to the underlying issue but a nice opportunity to do some cleanup too. Let me know what Y'all think, I can do a separate PR if necessary.

[pfeerick]

Not related to the body of this PR, so separate PR thanks. Especially since it will require figuring out which radios use what voltage levels, as it is not always "false".

[mha1]

Not related to the body of this PR, so separate PR thanks. Especially since it will require figuring out which radios use what voltage levels, as it is not always "false".

To conclude my OT discussion:
https://www.open-tx.org/2017/12/13/opentx-2.2.1RC3

https://doc.open-tx.org/manual-for-opentx-2-2/faq#voltage-on-frsky-radios-external-module-output

There is no mention of which (all?) FrSky radios are affected without testing real hardware. I suggest to leave the warnings and add a similar note to the EdgeTX user manual section https://manual.edgetx.org/color-radios/model-settings/model-setup/internal-external-rf / SBUS to check levels and if necessary to use protective measures like level shifters.

My apologies for having started the discussion here.

PS: I just received confirmation from a fellow modeller. X9E is at 10V (full VBat) with SBUS and PPM on the CPPM pin 😒