Is it possible: 8 motors in dshot?

Cube Autopilot
#21

Is anyone actually flying Dshot on ArduCopter today !?

I mean, actually looking at a log and seeing that 2048-steps resolution, not only having PWM_TYPE set to 3, 4 or 5 and trusting the FC to use the setting.

Because I tried my damnedest, on Pixhawk, Black and Orange Cube and Pixhawk4 Mini to no avail. Outputs are plain PWM no matter the settings. The BlHeli_32 ESCs are auto-detecting input signal, and will happily run PWM, so all my quads are flying, but I have these two “special” APD units, a 6S/40A and a 12S/120A that don’t understand PWM as input, and will take only Dshot300 and upwards, that I haven’t yet been able to spin a motor with.

I know I can do it with BetaFlight, but I want to do it with AC.

#22

@ThePara, I am sure that on my previous quad using the T-motor F55A 4in1 esc it was DShot150 (type 4).
I am sure also you did follow the steps at https://ardupilot.org/copter/docs/common-dshot.html maybe something is missing?
Gal

#23

Check a log. If your RCOU channels show values between 1000 and 2000, you were running plain PWM.

#24

Do I need to specify in the parameters whether I am using main or aux? Also will there be any difference between setting up dshot for a yellow and black cube?

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#25

If I understand your question than you need to change the servo functions to match motors on aux (33-36) on aux 1-4 and cancel the main to 0

#26

I think that PWM style values are logged even if the output is DHSOT or other - need to check.

EDIT:
There’s some discussion here:


Depending on the protocol and whether or not you have an IOMCU (cubes do) the logs will still show PWM values.

As far as I understand you can still only have 6 DSHOT outputs with a Cube.

#27

https://ardupilot.org/copter/docs/common-dshot.html

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So the following cautions apply:

  1. The 8 “MAIN” outputs of autopilots using an IOMCU (like PixHawk and Cube), cannot be used for protocols other than Normal PWM and OneShot. On these autopilots, only the additional “AUX” outputs can properly support OneShot125 and DShot protocols. If you attempt to set a “MAIN” output to DShot, then normal PWM output will occur, even though it has been set to a DShot protocol.
  2. For Pixracer and other boards without a separate IOMCU coprocessor, all servo/motor outputs can be used.
  3. Groups of outputs sharing a common timer, MUST have the same advanced configuration. Usually, these are specified in the autopilot’s hardware description linked from the Autopilot Hardware Options page. For example, if an output is configured for DShot in a group, then you cannot use another output in that group for Normal PWM ESC or normal PWM servo operation.

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#28

Just to be honest

My $300 experience with CAN was a real bust. I ordered 8 Cotleta20 from Holybro and I can not even express my disappointment with those. Aside from messy installation it had so much interference on IMUs I to use the NTF, I guess I could have used all those capacitors the provided with more mess.
So, I installed my two F55A in normal pwm and gone with all previous issues.

I ended up removing all can from herelink 2 as well, in my opinion the current ui tools including MP works only sometimes and for a hobbyist like me, it’s not giving an added value.
Just my 2cents

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#29

Also adding one more point to the list is that AUX 5 and 6 by default is set to Relay. These pins can be changed to Servo outputs by setting the BRD_PWM_COUNT parameter to 6 and setting RELAY_PIN and RELAY_PIN2 to -1. I couldn’t figure out why 2 of the motors are not running until I came across this in the ‘Servo’ section of the wiki.

#30

No, dshot is not compatible

Use a different ESC method

#31

Has this changed with ArduCopter 4.0? Is dshot possible with an X8?

#32

I had great success with dshot 4in1 ESC… made a X8 for a custom build… matter of fact I used 2 of them…wired them together and not a problem…I used 1 set if the 4in1 ESC for the top 4 motors and the 2nd one for the bottom 4… redundancy!

#33

With Cubes you could use DSHOT via the AUX outputs for one 4in1 and PWM via the Main outputs for a second 4in1 (or set of individual BLHELI ESCs) - this will give you BLHELI telemtry data from one set of ESCs.
You can not use DSHOT and get BLHELI telem data from 8 at once - maximum 6 via Aux pins.

You could of course use 8 PWM outputs to BLHELI ESCs and still have a lot of the advantages, just not the telem data, and still use the AUX outputs for other functions

#34

What are you talking about…they are compatible…

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#35

They are More than 1 way to skin a cat… in other words nothing is impossible!! That’s a word for quitting… if More people that believe that something was impossible then WW2 victory would not of been.

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#36

If you use FETtec ESCs and their “OneWire” protocol you can use up-to 12 ESCs on a single UART.
All the PWM outputs are free for other purposes.

FETtec ESCs are designed by one of the guys that created dshot. It’s simply better than DSHOT and telemety is included.