Assigning fan with M950 to expansion pins

[petriheino]

Hi,
I'm trying to define a new fan pin with Duet 2 using RRF FW 3.2.

I'm trying to use Expansion port pin 45 (Pin name TWD0) and define it as Fan0.
TWD0 has Firmware pin #3 in the Duet 2 Pinout tables.

I have tried with no effect (DWC doesn't create Fan0).

M950 F0 C"TWD0" Q250
M950 F0 P3 Q250
M950 F0 S3 Q250

Could the pinout table be old or has the definitions changed?
Or to define it as M950 F0 P3 is some additional step needed or is there another way to do this?
This pin is not listed in the RRF3 Pin names page

[droftarts]

@petriheino You cannot run a fan directly from the expansion header. The DueX uses a I2C expander chip + mosfets to drive the additional fans, and a 74HCT02 chip + mosfets to drive the additional heater heater outputs. See the DueX schematics for how these are connected, and to which pins: https://github.com/Duet3D/Duet-2-Hardware/blob/master/Duet_Expansion/Duex5v1.0/Duex_Schematic_v0.10.pdf

Looking at https://github.com/Duet3D/RepRapFirmware/blob/c3a666086bc30969c48514d9c05d50b028b31a00/src/DuetNG/Pins_DuetNG.h#L280 it looks like TWD0 isn't exposed, so may be being used for something internal.

Ian

[Phaedrux]

@petriheino said in Assigning fan with M950 to expansion pins:

Duet 2 using RRF FW 3.2.

Might want to update to 3.3 as well.

https://github.com/Duet3D/RepRapFirmware/releases/download/3.3/Duet2and3Firmware-3.3.zip
Upload that to the system tab in DWC.

[petriheino]

@droftarts Thanks, the link is helpful.

Im still trying to figure this out - assigning these and other Expansion header pins would make for cleaner wiring.

Could it work just by redefing pin properties PinCapability::wpwm?
And then giving it a name at PinNames?

Or would this require somehow deactivating the Duex from initializing?