Connection between Duet 3 6HC and SBC (Pi4)
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Hi Peeps,
Is there a definitive list/diagram designating the required connection between the Duet and Pi4 GPIO connector, as all the guides just state to use the supplied ribbon cable (https://github.com/Duet3D/DuetSoftwareFramework/wiki/SBC-Setup-Guide etc.), but I also want to use the GPIO connector for other uses, e.g. external 5v input, so I need to know what is actually required.
Thanks in advance..
Julian,
Old goat, learning new things….
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Both the 6HC and the Pi have alternate connections that can be used for the 5V supplies; they are preferable to the ribbon headers if possible.
The connector pinouts are given in a table half way down this thread:
https://forum.duet3d.com/topic/11540/duet-3-mainboard-6hc-initial-production-run/22You can also get splitter connectors such as these, to allow connection with the ribbon plug in place:
https://www.amazon.co.uk/GeeekPi-Connectors-Raspberry-Expansion-Compatible/dp/B088DB57RY -
@rjenkinsgb thanks for the info, but it looks like I'll still be chasing it out / testing, as the linked article doesn't show that the 3.3v line is needed, but the linked Git page, under troubleshooting, it states to check continuity of the line ??
The use of a splitter is limited, as I've fitted a full heatsink to Pi as I've had past issues with overheating .
Julian,
Old goat, learning new things….
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@dr_ju_ju The schematic for the Duet3 provides details of the pins in use at the duet end of things, it should be pretty straight forward to project them onto the rPi connector: https://github.com/Duet3D/Duet3-Mainboard-6HC/blob/master/Duet3_Mainboard_v1.01/Duet3_MB_Schematic_v1.01.pdf
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@dr_ju_ju said in Connection between Duet 3 6HC and SBC (Pi4):
The use of a splitter is limited, as I've fitted a full heatsink to Pi as I've had past issues with overheating .
You will almost certainly need a vertical extender then; I use full heatsink cases on my Pi's and the IDC connector will not fit directly, it needs an extended header.
Be sure to get one that has the proper square pins, many economy ones have thin pins that do not work well with other connectors.
You could stack a splitter on the extender?
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@gloomyandy yep, the link shown the circuit diagram of the Duet 3, but it does NOT detail the required connections between it, and a Pi4.
Also, I may well replace the Pi with either an Odroid/Pine64 device, so want what is actually required.
Julian,
Old goat, learning new things….
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@dr_ju_ju I've been using a GPIO shield for my Pi so I can use a Duet 3 with a Pi touchscreen:
For SBC mode you need:
You could use SPI1 instead of SPI0 or another GPIO pin instead of GPIO25, but that would require extra configuration steps on the Pi and in
/opt/dsf/conf/config.json.Duet software engineer
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@dr_ju_ju Page three of the schematic shows the connections to the SBC connector (and which pins within that connector are in use). Since this then connects to a simple ribbon cable and then to the rPi header it is relatively easy to work out the rPi connections. What is it that you think is missing? Other than the 5V supply (which needs to be provided to the rPi in some way), I'd say that all of them are required. You may be able to reduce the number of ground connections (or possibly use alternate ground pins on the SBC connector) but I'd be cautious about doing this as you may find doing so introduces noise problems.
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The wiring diagram on teh dozuki lists the pins in the connector, which I find easier to lay my hands on than the schematic.
https://duet3d.dozuki.com/Wiki/Duet_3_Mainboard_6HC_Wiring_DiagramIt lists the 3.3V connected.
What I've done for using other connections for other things (including injecting 5V to teh Pi) is to use a stacking header and a little bit of tri-pad stripboardbetween teh ribbon and the pi.
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@chrishamm Unfortunately the case I'm using works well, but severely limits access to the GPIO connector, i.e. it doesn't allow the use of a standard ribbon connector
Julian,
Old goat, learning new things….
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@dr_ju_ju said in Connection between Duet 3 6HC and SBC (Pi4):
it doesn't allow the use of a standard ribbon connector
Is it just the corners? It looks like a few minutes with a file would make it fit...
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@achrn Nah, its not just the inner corners, but the depth, and amount of material that is used for the mounting screws etc....
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@dr_ju_ju That's a shame (but I did kind of think if it was that simple you'd have done it already).
The Pi4 has better thermal and power management than previous Pis and consensus seems to be it actually tends to have fewer heat problems than less powerful models. Mine driving a MB6HC has been entirely happy with one of these: https://shop.pimoroni.com/products/raspberry-pi-4-heatsink but I understand you might want to stick with what is proven in your setup.
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@dr_ju_ju said in Connection between Duet 3 6HC and SBC (Pi4):
Unfortunately the case I'm using works well, but severely limits access to the GPIO connector, i.e. it doesn't allow the use of a standard ribbon connector
I use the same (or very similar) heatsink assemblies - they are fine with an extender added, eg. a header socket with wire-wrap style pins the IDC connector fits to.
The ones I found that have the proper square pins but still cheap were "Geekworm" 2*20 Pin female header kits
https://geekworm.com/products/geekworm-raspberry-pi-2x20-40-pin-gpio-stacking-header-extender-kitThey are available on Amazon etc.
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@rjenkinsgb I have some of those on order, but they appear to be lost in the xmas postal rush
BTW, your picture still shows that you are using the ribbon cable, which I do not want to use, so I still need what actually needs to be connected ??
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@dr_ju_ju said in Connection between Duet 3 6HC and SBC (Pi4):
Unfortunately the case I'm using works well, but severely limits access to the GPIO connector, i.e. it doesn't allow the use of a standard ribbon connector
????? I was responding to that post.
The required connections have already been linked in this thread, two or three times.
eg.
https://d17kynu4zpq5hy.cloudfront.net/igi/duet3d/33DEuEJZXP16vLbF.huge
