RFDesign TXMOD v2 with Yaapu telemetry script on FrSky Q7

I have a RFD868x and a RFD868x-TXMOD v2, both running firmware 3.38 (but newer versions should also work fine), and the ESP32 on the TXMOD is running version 1.46 (but newer versions should also work fine)

In the air I have an STM32 F7-based flight controller running ArduCopter 4.1.0-rc1 (but newer versions should also work fine) connected via telem2 to the RFD868x. The RDF868x also provides SBUS data to the rcin input of the autopilot. I did set the parameter RC_PROTOCOLS=8 to make 100% sure that it gets correctly decoded.

On the ground I have an FrSky Q7 running OpenTx 2.3.10 (but newer versions should also work fine) with Yaapu7 version 1.9.5-beta1 (but newer versions should also work fine)
Also using SBUS to communicate with the RC transmitter (20ms frames)
On OpenTX setup page 2/12 set External RF to:

MODE           SBUS
Ch.Range       CH1-16
Refresh        20.0ms     Normal
Output is      VBAT

Air rate 200Kbit/s, Mavlink2, max window 80ms, RTS/CTS, 115 baud and 256bit encryption. It works great so far.

The Ardupilot FrSky telemetry documentation contains step-by-step installation instructions.

And @xfacta did a detailed post on how to configure this

Many thanks to Yaapu, RFDesign and Shawn!

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Remember using the RFD radios for RC control it is vital to set the channel behaviour during failsafe conditions (link loss)

Thanks @amilcarlucas for prompting me to use SBUS with the TXMOD.
Actually using SBUS gives way less jitter than PPM and it respects throttle failsafe and radio failsafe (like lost link or radio died) so it is less important to set the channels to a desired output and use the PPM failsafe setting.
Of course it is still important that failsafes are set correctly and tested!

FYI: I am using Air speed 200, baud 115, max window 80 and RTS/CTS

Hi amilcarlucas,

I am trying to do the same, could you take a screen print of how to set it all up for SBUS on the air side? I see lots of SBUS options for RC input etc and I am unsure which do what.
I haven’t found any documentation so far which spells it out.

There are other posts on this forum that minuciously spell it out. Just do a little searching. What I did a bit differently was using a higher baud rate and activating AES256 hardware encryption

Use
Baud 115
Airspeed 200
max window 80
and look for the SBUSin and SBUSout checkboxes for the transmitter and receiver, SBUSin for the aircraft, SBUSout for the TXMOD.
Also you need to use the TXMOD web interface to set the WIFI speed to 115k baud too.

This should be fine unless you’re doing over 150km, and log downloads are good :slight_smile:

EDIT:
I also set the transmit power lower since I’m never going out of sight. TX Power 27

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HI Guy’s thank for the replies, Shawn thanks for the link. I was looking at the TXMOD manual 1.4, and it basically says that Version 3.09 the SBUS function is mapped to GPIO1.3, did either of you guys have to change the cabling or is it just mirrored on GPIO1.3??