Duet 2 Ethernet and SBC

A Former User

I'd say the first was about 40cm with questionable soldering, No Bueno... after revisiting it with crimps I'd say 20cm/26AWG(maybe it was 28?) and 15cm/30AWG loose wires, not in a ribbon. 470R resistor crimped in somewhere along the MISO, MOSI and SCK lines.

smoki3

@bearer

wired.... I don't understand why it is not working for me. My cables are less than 10cm, tried different resistors from 100 Ohm up to 500 Ohm. I soldered but this should normally better than just crimping. Also tried loose wires.

A Former User

It would surprise me if it was a signal integrity issue if it works for other operations than flashing, but at this point I'd get the scope out and take a look.

smoki3

@bearer no other things also doesnt work. Get checksum errors while homing for example

A Former User

Oh, I read the previous posts as if homing worked.

Can you run simple commands like M115 and M122?

smoki3

@bearer

So now I came a step closer. I disconnected the Duet2 from the VIN (24V Meanwell Power Supply) and power it over the USB Port from the raspberry pi. Now I can flash the firmware without any checksum issue.

@wilriker does this help?

dc42

What SPI speed have you configured in DSF?

smoki3

@dc42 the standard config 8 MHz

wilriker

@smoki3 Please try lowering it incrementally by dividing by two, i.e. try 4MHz, then 2MHz and so on until you either get to somewhere around 100kHz or find a working speed

I will try to reproduce your setup next week. Just to be sure: did you power the RPi from a buck-converter off of the Duet or did you power it separately?
Also if you only tried one of these options so far please try the other.

I also use loose wires of around 150mm length with Dupont crimps on the ends and several JST connector pairs in between to insert/remove resistors.

smoki3

@wilriker I tried a buck converter and a USB power supply - results in the same behavior.
As soon I disconnect the power from the duet and just plug in a USB cable it works with out any issues.

Lowering the speed doesn't help. Tried it down to 1MHz.

Actually I also use Dupont connectors with a cable length about 8cm.

smoki3

I now tried to lower the speed down toi 100kHz. But this also doesn't help.

Its really as I said, as soon I plug in VIN to the Duet the SPI Bus is broken

smoki3

Is there a reason why on my duet2 ethernet capacity C99 is not equipped? Is a capacity in the 5V buck converter.

I looked at the schematic normally there should be a 250uF capacity. Could this be a reason?

A Former User

which revision is the board?

wilriker

@smoki3 On my 1.03 board C99 is populated. My meter refused to measure the capacitance but it's certainly higher than "none".

@T3P3Tony might answer this question better if that would pose a problem (I'm primarily a software guy ).

smoki3

@bearer Its a 1.04c

A Former User

@smoki3 said in Duet 2 Ethernet and SBC:

1.04c

iirc its normal then, it was fitted to 1.04, 1.04a and 1.04b but not 1.04c.

also given the cpu and wifi runs off 3.3v with its own smoothing cap i'm not sure it matters, but I can try it next week if I manage to throw together a printed part with pogo pins for the wifi (edit: printed part is modelled for P50 + R50 pins, may need to drill out holes)

A Former User

@smoki3 seems I've missplaced or run out of pogo pins, and with logistis being what it is I doubt I'll test it any time soon.

maybe you could try soldering a regular radial through hole capacitor to the pads and see if it helps? (or see if Tony has anything to add)

smoki3

@bearer I don't have capacitor by hand

wilriker

@smoki3 First of all I can confirm that with external PSU I see the same behavior. I need to check the cause of that next.

A Former User

@wilriker said in Duet 2 Ethernet and SBC:

with external PSU

as in external 5v?