Duex 5 PWM output enables heater LED
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Is it expected that when the Duex 5 PWM 5V outputs are used that enabling them (e.g., with M42) causes the heater LED to light up corresponding to the heater that PWM output is tied to? The brightness also seems to correspond to the PWM value used.
I also note that the heater voltage is present (with no load obviously) at the terminals with the PWM pin is enabled.
My assumption is that this is normal and I've seen other users mention it but the behaviour is not documented so I want to confirm.
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@ardenpm Yes the5V "servo" PWM control channels are shared with the heaters:
5 servo outputs with 5V power and 5V signal levels, sharing control channels with the heaters. So you can use unused heater channels to drive servos.
https://duet3d.dozuki.com/Wiki/Duex2_and_Duex5_Features#Section_Hardware_specification
and in the wiring diagram:
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Thanks for the clarification. While it might be obvious to a hardware person that sharing them would mean the heater and LED also gets enabled, it might be worth adding a note to that effect.
While I had already read all of the linked information, it wasn't clear to me whether software configuring the pins for use as PWM for servos etc does anything special or just tells the firmware how to map them.
