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Thread: DCDC-USB minibox

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    DCDC-USB minibox

    I have bought this converter http://www.mini-box.com/DCDC-USB.
    I will use it with default automotive settings, but need to do one modification.
    Power switch which connects to motherboards power button only needs to turn OFF CarPC when ignition goes to OFF state.
    I have bought fitPC2 and when it senses voltage it turns ON by itself, so I don't need this function from DCDC-USB converter, I only need shutdown function and all other standard options which are in "automotive" mode.

    Any idea how to do this?
    Thanks.

  2. #2
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    Quote Originally Posted by kish89 View Post
    I have bought this converter http://www.mini-box.com/DCDC-USB.
    I will use it with default automotive settings, but need to do one modification.
    Power switch which connects to motherboards power button only needs to turn OFF CarPC when ignition goes to OFF state.
    I have bought fitPC2 and when it senses voltage it turns ON by itself, so I don't need this function from DCDC-USB converter, I only need shutdown function and all other standard options which are in "automotive" mode.

    Any idea how to do this?
    Thanks.
    I think the easier way would be to disable your FitPC2 turning on automatically when current starts flowing. It most likely can be done in the BIOS, maybe an option like "On Power" or "On AC" - you want to disable it. Then, let DCDC handle the On/Off procedures by itself.

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    Well, for sure that would be easiest way, BUT this can't be changed in BIOS, it can be turned off by modifying fitPCs power supply, but then I'll lose warranty.

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    Quote Originally Posted by kish89 View Post
    Well, for sure that would be easiest way, BUT this can't be changed in BIOS, it can be turned off by modifying fitPCs power supply, but then I'll lose warranty.
    So the function of a computer automatically turning itself on whenever power is provided is hardwired and can't be disabled without hardware modifications? I'm really not sure that that is correct.

    EDIT: Or is a power switch directly on the power supply?

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    Yes, 100% positive

    Actually motherboard and power supply are all-in-one solution, everything on single PCB, but power button works just like on standard desktop PC case with ATX power supply.
    Last edited by kish89; 09-20-2011 at 02:30 PM.

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    I'm still not understanding this correctly - if the power button works just like on a standard desktop PC, wouldn't pressing it turn the computer on if it was off before, and vice versa? I had a similar issue - I used a small all-in-one computer as well - I found the two contacts that the button shorts and soldered the On/Off pins from DCDC to them.
    But what you are saying is that the computer turns on automatically when power is supplied and the power button is only for turning it off?

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    fitPC has hardwired "turn ON after power loss", so when you disconnect +12v feed from fitPC(turn car OFF) and reconnect it(turn car ON), it turns automaticly ON, and you can't change this (I have asked customer support).
    Of course, there is a "classic" ON/OFF switch for turning it on/off, because most users are using it as classic desktop PC so they are not disturbing power feed.

    So if I leave turn ON signal on DCDC this will happen:
    1.Turn car ON
    2.DCDC gets ignition and feeds +12V to fitPC
    3.fitPC turns on because of integrated "turn ON after power loss" function
    4.DCDC sends ON signal to fitPCs power switch
    5. fitPC powers OFF (because it was ON and DCDC sent impuls which had turned it OFF)
    Last edited by kish89; 09-20-2011 at 03:42 PM.

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    Quote Originally Posted by kish89 View Post
    fitPC has hardwired "turn ON after power loss", so when you disconnect +12v feed from fitPC(turn car OFF) and reconnect it(turn car ON), it turns automaticly ON, and you can't change this (I have asked customer support).
    Of course, there is a "classic" ON/OFF switch for turning it on/off, because most users are using it as classic desktop PC so they are not disturbing power feed.
    Wow, that is bizarre. But I see what you are saying.

    DCDC-USB has a mini-usb port and a configuration utility. There's a "script" mode - try playing around with that: see if you can set the output voltage 0V until the power on signal is sent (so it's naturally ignored by a computer that's not powered) and then raise the output voltage to 19V (or w/e your computer takes). So if the turn on signal is sent 3s after ignition, enable Vout after 4s. Shut down should be pretty straightforward.
    There's also a parameter that tells the power supply how long to wait when ACC power is on before sending On signal to the motherboard. I think you can probably tweak this value so that when your computer receives it, it will ignore it. It's pretty hackish, but try this:

    1. Plug in your FitPC (it should auto-turn on)
    2. Let it boot
    3. Shut it down
    4. From that state, start experimenting: press power button once to turn it on. Then press power button again almost immediately. Did it turn off? If not, then it will ignore the second power button signal if it comes too close to the first one. If it did turn off, see how long it takes for the Windows loading screen to show up: I'm pretty sure your computer will ignore the power signal unless you press and hold it for >4s - that will shut it down hard. Keep adjusting the value so your computer ignores the power signal sent by DCDC

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    i think i remember other members here using the fitpc, and not asking the same questions, so i am inclined to wonder if your being over-worried about the issue.

    have you connected everything to verify that the board does not operate correctly with the default dc-dc usb settings?

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    Quote Originally Posted by nivanov View Post
    Wow, that is bizarre. But I see what you are saying.

    DCDC-USB has a mini-usb port and a configuration utility. There's a "script" mode - try playing around with that: see if you can set the output voltage 0V until the power on signal is sent (so it's naturally ignored by a computer that's not powered) and then raise the output voltage to 19V (or w/e your computer takes). So if the turn on signal is sent 3s after ignition, enable Vout after 4s. Shut down should be pretty straightforward.
    There's also a parameter that tells the power supply how long to wait when ACC power is on before sending On signal to the motherboard. I think you can probably tweak this value so that when your computer receives it, it will ignore it. It's pretty hackish, but try this:

    1. Plug in your FitPC (it should auto-turn on)
    2. Let it boot
    3. Shut it down
    4. From that state, start experimenting: press power button once to turn it on. Then press power button again almost immediately. Did it turn off? If not, then it will ignore the second power button signal if it comes too close to the first one. If it did turn off, see how long it takes for the Windows loading screen to show up: I'm pretty sure your computer will ignore the power signal unless you press and hold it for >4s - that will shut it down hard. Keep adjusting the value so your computer ignores the power signal sent by DCDC
    That is actually a pretty good idea
    I didn't try it yet, but Im sure that it will ignore second push power button in some phase of booting.
    Thanks!

    Quote Originally Posted by soundman98 View Post
    i think i remember other members here using the fitpc, and not asking the same questions, so i am inclined to wonder if your being over-worried about the issue.

    have you connected everything to verify that the board does not operate correctly with the default dc-dc usb settings?
    I think that all models from 2011 year have this option hardwired by default, older models did not have it.
    With default settings, sometimes everything is ok, sometimes not(fitPCs shutdowns)
    I will try to modifiy "wait time "on DCDC when to send PWR impulse.

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