FMUv5 F-Port FrSky supported?

yuri · June 11, 2018, 5:53pm

Hi,

Does anyone here know if F.Port (FrSky) is supported/developed on the Holybro Pixhawk 4 FMUv5 F7?

Thx,
Yuri

bkueng · June 18, 2018, 5:56am

Hi

It’s not in development but would be nice to have.

yuri · June 18, 2018, 7:09am

I’m willing to have a look at it, but I’m new to px4 so would need quite some pointers from experienced devs…

bkueng · June 18, 2018, 10:22am

Great!
Here some initial pointers:

FrSky telemetry is implemented here: https://github.com/PX4/Firmware/blob/master/src/drivers/telemetry/frsky_telemetry/frsky_telemetry.cpp
RC parsing library is here: https://github.com/PX4/Firmware/tree/master/src/lib/rc
Then it gets a bit complicated because of the IO chip: RC goes through the IO e.g. on Pixhawk 4. This is simpler for example on the Pixracer, where RC is directly parsed in the fmu driver: https://github.com/PX4/Firmware/blob/master/src/drivers/px4fmu/fmu.cpp#L1551

I’m not sure if it’s worth adding F.Port support for boards with an IO due to the required amount of changes (though we could work around it by using another UART for RC).

Feel free to ask me further questions.

yuri · June 24, 2018, 5:55am

Ok, I only have a pixhawk 4 (holybro) to test on so it would be nice to get it working through io…
I hope to find some time next week to look into the rc code.
Why does it go through IO? Is there a guide/blog that explains px4 on a medium level?

bkueng · June 25, 2018, 6:00am

Because of failsafe: if the main FMU fails, the IO can still operate on its own (though this is only for fixed-wing to fly fully manual).

The best reference is probably this: PX4 Architectural Overview · PX4 Developer Guide

zwn · October 10, 2019, 11:29am

Has the status of F-Port support changed? It would be nice to have one less cable to worry about

bys_1123 · April 19, 2020, 12:03pm

I’m also looking forward to this!

bys_1123 · June 12, 2020, 6:14pm

IO failsafe is a very rare situation, I think support f.port first on a uart on FMU is enough for most of users.

elromulous · July 30, 2021, 6:12am

Resurrecting this thread. Has the status of this changed?

Seeelefant · November 7, 2021, 12:37pm

Do we have any news on this topic? For Arducopter it´s working for quite a while

roman-dvorak · November 7, 2021, 12:52pm

Hi, I wanted to extend PX4 support for this protocol. But I came across an error that I was not able to connect the receiver to the FMU. More information about this issue is here:

github.com/PX4/PX4-Autopilot

Inverted UART (for FRsky telemetry) does not work on FMUv5 (CUAV NANO). Is not inverted.

opened 06:48PM - 11 Oct 21 UTC

roman-dvorak

**Describe the bug** Inverted UART does not work. Is not inverted. I tried to m…ake FRsky telemetry (S.port) work. And I was unable to get in working. After some time, I looked at it with an oscilloscope. And the data from the autopilot looks like this: ![image](https://user-images.githubusercontent.com/5196729/136836921-d209a3ab-fbe6-4658-9ed7-ea2f54b0f339.png) It was tested with CUAV V5 nano (FMU v5 STM32F765). Telemetry was enabled in parameter to some TELEM port. (Several ports have been tested with the same result). FRsky telemetry driver started correctly in the correct mode (single wire, inverted). ![image](https://user-images.githubusercontent.com/5196729/136837327-199396ce-4bb2-4ca8-8c44-2ccf127f5c1e.png) https://github.com/PX4/PX4-Autopilot/blob/801ef2d5200a31e8a801a5d6b0faf0aec18be7ef/src/drivers/telemetry/frsky_telemetry/frsky_telemetry.cpp#L384-L387 Level 1 in the time inactivity is forced by autopilot. Although an internal pulldown should be connected. https://github.com/PX4/PX4-Autopilot/blob/801ef2d5200a31e8a801a5d6b0faf0aec18be7ef/src/drivers/telemetry/frsky_telemetry/frsky_telemetry.cpp#L201-L213 After researching the firmware, I made sure that the IOCTL is written (but i don't know if it's set ). I tried to hardcode it in FRsky driver. It does not help. There are several problems: - Is hold in a high level (Internal pulldown should be set) - Data are not inverted (it should) Data from the FRsky receiver looks correct and inverted. And autopilot responds to them. Upon further research, I found that this feature is included in NUTTX for this FMU. (I didn't check it in the processor documentation). And on the forum I found a person who also deal with this issue (for another purpose): https://discuss.px4.io/t/dynamixel-servo-on-px4/22995 Therefore, I think it's a problem in some lower-level of the UART driver. **Expected behavior** I assume (minimally) that in the inactive state it should be in Log0. **Connection** I have connected S.port of FRsky receiver directly to TX pin of autopilot's TELEMx port. **Additional questions** - Has it been tested that FRsky directly connection to RC transceiver works? - Is FMUv5 a supported platform for that feature (especially CUAV NANO V5)? I can't find exactly this information anywhere. But in NUTTX this property is defined for STM32F765

ticotico · January 20, 2022, 9:53am

Would also love to see support for F.Port!

dk7xe · March 13, 2023, 3:59pm

yep, F.PORT would be awesome since it supports bidirectional communication (telemetry feedback as well)