telemetry baud rates / Protocol+UsrProto choices & arduP

er9x is the best known firmware. It has a superb range of features and is well supported by the community. Well worth trying out.
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Country: France

telemetry baud rates / Protocol+UsrProto choices & arduP

Post by nvd07 » Sat Jul 17, 2021 9:57 pm

I did some experiments with two OrangeRx 433Mhz 1w modules :
- first with UltimateLRS 2.36 firmware ( ... =5&t=13430)
- then, as the licence expired, I tried more recently with OpenLRSng 3.8.5 Gitsly firmware

In both cases I had a Mavlink connection between the PC ( Mission Planner ) via a HC-06 bluetooth stick wired to the OrangeRx433 module of my 9x and at the other end, the OrangeRx433/F405CTR-ArduPlane. :) In parallel I have been able to display the telemetry onto the er9x ArduP screen ( thanks to Mike's APM-MAvlink-to-Frsky translator on an arduino pro mini).

:arrow: However in both cases with my er9x I have not been able to get both the ArduP screen and the functional RC channels at the same time :? , I believe this is because I have a mismatch in my baud rates, compared to the Telemetry Baud Rates expected by er9x, based on my menu choices:

( it was similar with UltimateLRS a few weeks ago, but could not test long enough. )

-I can get the ArduP screen populated, by incorrectly setting the Protocol to XJT for example ( which means er9x will be unconditionally listening at 57.6K if I am correct ) but at the same time I lose my RC channels (as er9x is sending PXX instead of the PPM that the OpenLRS and flight controller are expecting).
-At the opposite, when I set Protocol correctly to PPM, the channels work fine ( all the way to the servos ), but the ArduP and other telemetry screens are no longer populated (as my Mavlink is running 57.6K at the OrangeRx serial ports, both inside the aircraft and on the ground, whereas er9x might be expecting 9600?).

12:14:26.448 -> openLRSng
12:14:26.448 -> 3.8.5 - System configuration
12:14:26.448 -> 5) Hop channels: 1,30,8,24,14,19,5,35
12:14:26.448 -> 6) Datarate (0-2): 2
12:14:26.448 -> 7) Channel config: 8
12:14:26.448 -> 8) Telemetry: Transparent (Mavlink)
12:14:26.448 -> 9) Serial baudrate:57600
11:09:32.769 -> openLRSng 3.8.5 - receiver configurator, rx sw 3.8.5Use numbers [1-D] to edit ports [E-Q] for settings
11:09:32.923 -> RX type: 1) port 1function: PPM
11:09:32.923 -> 2) port 2function: LBEEP

Now, I also saw that recently ( April 20 ), in order to work with the newest QCzek LRS needing SBUS, version 822x was introduced, allowing to select Telemetry:UsrProto=Frsky(Sport) at 57.6K bauds at the same time as Protocol:SBUS. I did not understand though, if prior to 822x this choice was not possible at all, or if it used to be Frsky at 9600 (if this even exists...).

Today I also considered changing the settings in ArduPlane , to accept SBUS rather than PPM; after some reading I did not go this way ; I think the two 433Mhz systems I tested are the opposite from the direction taken by the latest Qczek LRS firmware for E32 hardware :
-Ultimate LRS 2.36 requires PPM
-OpenLRSng Gitsly 3.85 seems to require PPM for anyone intending to run Mavlink, because although SBUS exists, it would rule out 'MAVlink transparent serial' (due to lack of HW ports) ... controller
So, probably both firmwares are limited to PPM because of the same OrangeRx hardware limitations.

:?: so I have the following questions about telemetry baud rates in er9x 822x/y/z,

:arrow: 1) when the main Protocol is set to SBUS, is the expected baud rate for telemetry 9600 for all UsrProtos except UsrProto:Frsky(Sport), but 57.6K for UsrProto:Frsky(Sport) ?
:arrow: 1.1) if so, is there a reason why Protocol:SBUS + UsrProto:Frsky can be at 57.6K but Protocol:SBUS + UsrProto:ArduP would remain at 9600 rather than 57.6K ? ( I woud not benefit from SBUS now - but I have E32 modules on order, if they ever get delivered to me, later I will try QCzek LRS too )

:arrow: 2) when the main Protocol is set to PPM, would er9x always listen to telemetry at 9600 bauds, regardless the Telemetry:UsrProto = Frsky(Sport) , ArduP, ... ?
:arrow: 2.1) if so, is it required for compatibility reasons - if PPM is the only way with older DJT modules, or something like this ? I am asking because 9600 is the lowest of the range I have seen.

(I ruled out all other baud rates : I read about 38400 too but came to the conclusion it would be only found in the special build : er9x-ardupilot.hex.
I read about 100K bauds but it seems to be specific to the 4-in-1 mutiprotocol module (so Protocol=MULTI) ... except it would switch to 57.6K when Sub_Proto is Frsky-X. :!: edit: it even goes from 125K down to 9600 there are more cases ... #L785-L789 )

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