Duet 2 Ethernet and SBC

A Former User

@T3P3Tony said in Duet 2 Ethernet and SBC:

We are considering a small hardware board to provide the physical interfacing and signal buffering.

if the series resistance is deemed all that is needed, then a few crimps and a printed part goes a long way:

Btw, is there a part# for the nylon stand offs? gonna try a pogo-pin version for the Wifi

gtj0

Jeez. I take some time off and this happens.

smoki3

@wilriker
Today I am back from holidays. I tried to investigate a bit more but it does not help. I disassembled the Duet 2 Ethernet from my printer so I have no other cables in the near of the board. I also made a new cable out of a shielded ethernet cable to avoid any EMC troubles. But still the same. If I try to flash the firmware for example I get many checksum errors.

@bearer
are you now able to flash the firmware over DWC? I always get checksum error.

A Former User

@smoki3 said in Duet 2 Ethernet and SBC:

are you now able to flash the firmware over DWC?

with both the Wifi and Ethernet (Duets) yes

smoki3

@bearer so I mean with the SBC connected

Which raspberry do you use?

A Former User

yes yes, update wifi and ethernet boards with RRF3.2 over SPI from the SBC, Once I shortened the wires and had my novice crimp the resistors instead of trying to solder its all good at 8Mhz.

edit: one 4B 4GB, 3B+ and some 2B tested.

smoki3

@bearer How short are your cables?

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?