ATX pico PSU startup

Discussion in 'UDOO BOLT' started by RedMod, Oct 27, 2023.

  1. RedMod

    RedMod UDOOer

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    Hello to all,
    my Bolt traveled from me to my son, and now i want to reuse it as a NAS box.
    My idea is to purchase a pico PSU with 19 Volts DC input, so i can use one power brick to power both the bolt and the ATX pico PSU.
    The PSU will also power 4sata disks and a M.2 to PCIEx16 riser slot for my ServeRAID 1015 controller.
    (I could also use a M.2 to sata or mini-sas card, but those seem to run on the not recommended asmedia chips.)
    So to my question:
    I would like to power on the bolt and the psu with one button. Is it possible to use the adruino pinout for that?
    So that when the bolt powers on it will short the two atx pins to start it?
     
  2. NickGR

    NickGR UDOOer

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    I think you need to short the EC pin6 (Wake#) on the Bolt, and ofcourse the Green wire on the ATX PSU.
    As for the method you could always follow one of the guides online like https://www.instructables.com/Using-the-Raspberry-Pi-to-control-an-ATX-power-sup/
    But do make sure to NOT CROSS the pins as the PSU PS_ON# is 5V and the Bolt Wake# is 3.3V.
    So use two seperate pin on the arduino, one pin to control the PSU, and another pin to control the Bolt.
    Also I do not really know as I have not tried it, I think the Wake# will need only enabled momentarily as it will work as a normal power button, keep it pressed and it might turn off again. But that you will have to check your self.
     
  3. RedMod

    RedMod UDOOer

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    Thank you NickGR, for your reply :)
    I was reading the article from your link and the documentation from udoo:
    ---
    The Wake pin can be used as an interrupt, the signal is caught by the EC and propagated to wake up the main AMD Ryzen™ processor from S3/S4/S5 status (Suspend/Hibernate/Power Off).
    The Wake is available at Pin 6.
    Pin Function EC PAD
    6 WAKE# GPIO025
    The wake signal is activated by a logical state change on the Pin (e.g. active low from 3.3V to GND).
    ---
    So if i understand correctly, when the bolt is turned on, or powered off, the wake pin with ground makes a 3.3V impulse.
    That means, i could use a 4 contact 2+2 switch that would short independently UDOO PIN6+GND and The PSU Green 5V+black ground at the same time?
     
  4. NickGR

    NickGR UDOOer

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    The ATX PSU will need to be permanently pulled low to be kept working and released high to shut down, so with just a pulse it will not do much at all.
    Also I believe the Wake# pin works as a normal power button for the Bolt, which means with momentary short it will either wake the processor or send signal to the OS for shutdown, but if you keep it shorted for more than 4-10 seconds it will force shut down bypassing the OS.
    You could always make the Bolt turn back on automatically when AC is back in the BIOS, and keep the ATX PSU shorted permanently, then you could just power both on and off from a single switch on the main AC. Infact this is how I am turning my Bolt on as I usually have plenty of power failures and need it powering it self up when the power comes back.
     

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