Is there a way to debug accelerometer connection issues?

OwenD

OK.
I just tried wiring directly to the LIS3DH using 150mm jumpers and it works!
Screenshot_2021-05-01 3Dprinter(1).png

Strange that the other cable works on an arduino.

Would it be better to use cable that has twisted pairs?
I thought the shielded cable would be a good option.

Diamondback

@owend What kind of cable are you using? Another user and I had good success with USB 3 cables (mine is 3m long).

OwenD

@diamondback
I was using 9 core shielded
https://www.altronics.com.au/p/w2712-9-core-shielded-data-cable/

I'm about to try some CAT5 data cable (4 x twisted pairs)
I'll report back.

Diamondback

@owend Ok, I tried single twisted pairs first, ie basically the inner part of CAT 5 cable without any shielding, and that didn't work for me. The USB cable is both twisted and shielded multiple times, I connected all the shielding to GND as well.

OwenD

Success!
For me a piece pf CAT5E cable worked.
I'm reasonable confident the connections on the first cable are sound.
Perhaps a better choice would be the USB cables suggested or maybe CAT6 shielded cables?

Now I have some data...
Just have to work out what to do with it

Diamondback

@owend said in Is there a way to debug accelerometer connection issues?:

Success!
For me a piece pf CAT5E cable worked.
I'm reasonable confident the connections on the first cable are sound.
Perhaps a better choice would be the USB cables suggested or maybe CAT6 shielded cables?

Now I have some data...
Just have to work out what to do with it

Awesome!

zapta

@owend said in Is there a way to debug accelerometer connection issues?:

Perhaps a better choice would be the USB cables suggested or maybe CAT6 shielded cables?

An oscilloscope would allow you to look at the signals and see if they are missing or distorted.

OwenD

@zapta said in Is there a way to debug accelerometer connection issues?:

An oscilloscope would allow you to look at the signals and see if they are missing or distorted.

True. But out of the reach of many of us.
In my original post topic I was hoping that RRF could somehow self diagnose communication on each pin.
It seems like it's going to be pretty critical to get cables just right for this to work.

zapta

@owend said in Is there a way to debug accelerometer connection issues?:

True. But out of the reach of many of us.

That's correct. Digital oscilloscope prices went down very significantly but it's still a significant amount of money.

I was hoping that RRF could somehow self diagnose communication on each pin.

Let's see if future generations of Duet boards will have an accelerometer connector that will work out of the box with the optional Duetcelerometer module.

dc42

I have made the accelerometer SPI clock frequency configurable and reduced the default from 4MHz to 2MHz. I expect this will make it easier to obtain a connection. These changes will be in RRF 3.3RC1.

clownsrache

What kind of issue do i have?

1.5.2021, 15:42:23: M955 P0 C"spi.cs2+spi.cs3": Accelerometer 0:0 with orientation 20 samples at 1344Hz with 10-bit resolution

M956 P124.0 S10 A0

1.5.2021, 15:45:43: M98 P"0:/macros/ACC": Error: Response timeout: CAN addr 124, req type 4014, RID=0

dc42

@clownsrache after sending that M955 command, what does M955 without parameters respond with?

dc42

RRF 3.3RC1 with configurable accelerometer SPI frequency is now available at https://github.com/Duet3D/RepRapFirmware/releases/tag/3.3RC1.

tekstyle

@diamondback how would u use a USB cable? it only has 4 wires but we need 7 for the adafruit accelerometer

dc42

@tekstyle I have had good results with ribbon cable, ensuring that the CS wire is not next to any other signal wires. See the images and description at https://duet3d.dozuki.com/Wiki/Accelerometers#Section_Direct_SPI_connection_to_a_Duet_main_board.

Diamondback

@tekstyle said in Is there a way to debug accelerometer connection issues?:

@diamondback how would u use a USB cable? it only has 4 wires but we need 7 for the adafruit accelerometer

Use an USB 3 cable It has 8 wires.

tekstyle

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