External 5V supply for SBC Raspberry Pi 4 and Duet 3 Mini 5+

j.pickens

I am confused by the jumper diagrams for the 5V SBC jumpers.

I have a 24V to USBC power supply for the raspberry pi 4, as the documents say the Duet 3 may not have enough power.
My supply should be sufficient to power both the Pi and the Mini.

Can I power the Duet 3 Mini from the Pi via USBC on the Pi and the 26 pin ribbon between them?
If so, what jumper settings should I use? One says 5V ext, the other says 5V SBC.

Alternately, I can use the internal Duet 3 Mini power, and power the Pi with the USBC on the pi.
In this scenario which jumpers to use? I'm thinking no jumpers installed, but I am confused.

The section on powering the SBC says there are 4 ways to go, but there are 3 diagrams and no linkage between the 4 ways described and the diagrams.

Perhaps a diagram with wiring and jumper examples is called for here.

Help is appreciated.

droftarts

@j-pickens

Can I power the Duet 3 Mini from the Pi via USBC on the Pi and the 26 pin ribbon between them?

Yes, you can power the Mini 5+ 5V from the Raspberry Pi; put a jumper between '5V_SBC' and '5V_COM' on the 5V SELECT pins, and put another jumper on 'Internal 5V disable' (I've added this to the Mini 5+ documentation here ). This can power the logic side of the Duet, but that can't supply power for motor drivers and heaters.

Alternately, I can use the internal Duet 3 Mini power, and power the Pi with the USBC on the pi.

That should be fine. Powering the Mini 5+ and RPi separately is what we generally recommend.

The section on powering the SBC says there are 4 ways to go, but there are 3 diagrams...

I think you looking at the Duet 3 6HC documentation here? This is similar to the options the Mini 5+ has, ie internal 5V, external 5V, and 5V from SBC, though the 6HC (v1.02 and later) doesn't have an 'Int_5V_Disable' jumper. The fourth option is 5V power by USB, which is the same as the Mini 5+.

Ian

j.pickens

@droftarts Thanks, I'm running it with the onboard power for the Duet3 and separate 5V power to the Pi. Running with NO jumpers, which I think is correct. Does this sound like the correct combo?

Vader019

@droftarts Curious, where can one purchase that 26 pin ribbon cable? I am setting up my DUET 3 also with a raspberry pi 5 but I'm missing the ribbon cable. Is that something i can buy off amazon? i got the the web interface on the pi to work but its stuck on connecting which I'm assuming is cause of the cable.

droftarts

@Vader019 It's a generic 26 pin (Duet end) to 40 pin (RPi end) ribbon cable, so you may be able to find/adapt one.

If it's a Duet3D board, you should have got one in the box. Email sales@duet3d.com for a new one.

Not that many pins are used on the expansion header, so it's possible to use individual patch wires to connect the Duet 3 and RPi: https://docs.duet3d.com/Duet3D_hardware/Duet_3_family/Duet_3_Mainboard_6HC_Hardware_Overview#wiring-diagram

You need pins 17, then 19 to 24, with 20 as a GND. They should match the RPi expansion header pinout:

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Ian