Change in default PS_ON state in 3.4?

[zapta]

I switched recently to 3.4 stable and it seems to have a different default state of PS_ON.

With 3.4, if config.g has no M80 or M81, PS_ON output seems to start in the CLOSED state (that is, active pull down). IIRC, with previous versions, it started in the OPEN state (pull down inactive).

Is it so? Is it intentional?

[Phaedrux]

From the change log:

There is no longer a power supply control pin assigned by default (in previous firmware versions, PS_ON was assigned by default). Therefore, M80 and M81 will not work until you have assigned a power control pin. If you want to control the power supply, you should use assign a pin using either M80 or M81 with the C parameter in config.g. Use M80 if you want to start with power on, or M81 if you provide separate 5V power and you want to start with VIN power off.

https://github.com/Duet3D/RepRapFirmware/wiki/Changelog-RRF-3.x#reprapfirmware-340

Does that account for what you're seeing?

[zapta]

@phaedrux said in Change in default PS_ON state in 3.4?:

Does that account for what you're seeing?

Thanks @Phaedrux. I am aware of the need to add C"pson" to the first M80. My question is about the state of the pson port before any M80 or M81 is issued.

My observation is that in the past (including with 3.4.0beta5), when the Mini5 started and before any M80/M81 was issued, the pson output was inactive (pson open, not pulling to ground) and that now with 3.4/stable it's active (pulling to ground).

Is it so? Is this change intentional?

(I notice behavior change in my system, I do not probe random pins for nit picking )

[dc42]

@zapta there has been no change to the default state of the PSON pin in RRF 3.4.

[zapta]

Thanks @dc42.

The duet is fed from external 5V and the PS_ON output controls a mains power relay. With previous versions, when I reset the duet via the Emergency Stop function, the relay power cycled off and then on again. Now it doesn't. Is this expected?