Functionality differences among Pixhawk Flight Controllers

In recent message threads I’ve been trying to learn more about MAIN and AUX ports and DSHOT.

It’s made me wonder how much of the functionality is tied to the hardware, and how much is tied to the firmware.

There’s a major focus on CubePilot flight controllers within the ArduPilot community. I’d like to know how much the flight controllers from different vendors affect certain issues.

For example, the Orange cube does not function properly on AUX-1 for passthrough. Do other flight controllers in the Pixhawk family (CUAV, Holybro, etc) have the same problem - or do other flight controllers not have that issue?

Similarly, do some of the DSHOT and bi-directional DSHOT issues and problems have to do with a fundamental Pixhawk hardware issue - or are the problems the result of ArduPilot firmware?

Thank you!

The DSHOT limitation is a hardware issue when it comes to aux vs main. Many autopilots have this restriction - but some do not.

Also the Pixhawk family has no other meaning other than different companies decided to jump on the name because it was the most popular autopilot back in the day. The Orange Cube is actually NOT a Pixhawk.

The ones that don’t are without an IOMCU.
If anyone has a use for an IOMCU other than a Plane or perhaps Trade Heli raise their hands :slight_smile:

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Yep - I don’t necessarily know what the benefit is for having control split between the FMU and IOMCU.

@proficnc Any hints on if Cube Red will be the same as Orange with the 8+6 split?

Thank you. That’s helpful.

Perhaps all that matters is if there’s an ArduPilot build for a flight controller or not.

When there are problems however, it would be helpful to know if its a hardware problem, or an ArduPilot firmware problem.

For example - can I switch to a HolyBro flight controller to get around the AUX-1 Pass-through problem? The DSHOT problems? From your comments, it sounds like some flight controllers handle DSHOT Ok. Would you have a suggestion on how to find out which ones?

Of course some other flight controller may have it’s own problems.

I guess at this point it would help if I had answers to three questions:

  1. What is the definition of a “pixhawk” flight controller.

  2. What modern flight controllers are truly “pixhawk.”

  3. In what way is the Orange cube not a “pixhawk.”

again - many thanks!

Almost all autopilot websites list how many ports can do DSHOT in their manual (at least I know Holybro, mRobotics, Proficnc, and CUAV do).

Pixhawk is just a name that caught on - its like how people call tissues Kleenex even though there are a slew of other models/brands. There is nothing special that makes a flight controller a pixhawk - and there is no benefit to a flight controller that is dubbed a “pixhawk”.

Google “Lorenz Meier pixhawk”

And agree with @manavgandhi17

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If you want the lore - after the first Pixhawk came out and then everyone just started adding numbers to the end to make it sound like their autopilot was better. Pixhawk 3, 6, 1000, etc. :laughing:

Pixhawk 1


Or the reverse, calling it “Classic” :slight_smile: And it was like a Classis car where you could pay ~$300 for the same or less functionality than a modern $60 board. It might have even been made in Mexico going it even more status.

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Really interesting stuff.

I guess the story of the open source electronics that define “pixhawk” is an urban legend.

Interesting that the CubePilot standard carrier board has “pixhawk” printed on it. No wonder there is confusion!

Any idea that the deal is with the FMU versions on some of these - such as the Holybro “pixhawk” flight controllers?

Actually mRo has a classic Pixhawk that can do 14 DSHOT outputs lmao

Sure, Dronecode defines that. Which Ardupilot plays no part in.

So the Cube Black used the same carrier board was under the Pixhawk name (Pixhawk 2.1) and I think they also decided the Pixhawk name was being thrown around too much now.

Yes, the Control Zero version of the Classic. Cool FC. The original one didn’t last long, I can’t imagine they sold many.

how many levels deep does this go :laughing:

I imagine the Pixhawk Classic was actually based on the Pixhawk 2.4.8 which are just clones of the Pixhawk 1.

I think it was billed as an original 2.4.6 but for sure with 2Mb flash like the very last of the 3Dr ones. Same guy Jordi Muñoz
That 2015/2016 time frame was an interesting time to be in the hobby!

Looks like this is the open source “pixhawk” standard definitions:

Now two questions -

  1. Do any flight controllers follow these standards to the letter?

  2. In what way do the major flight controllers deviate from the standards.

I suppose for every distinct flight controller, there has to be a specific ArduPilot firmware build for it. I can just imagine the tasks involved to accomplish that.

I just run h7 matek controllers now, the version i choose is a stack with the pm on the bottom and the fc on top, they are awesome and there is nothing pix about them.
Just choose hw that has all the options/features you need for your build and has ardupilot fw available for it.