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Re: [LinkStation_General] Restart on Power Failure?!

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  • KeepIt SimpleStupid
    Power on resets in general are a PITA. A good control element to use for push buttons etc. is a LED/FET like the VACTEC VTL5C1. It s a nice package with
    Message 1 of 14 , Jan 3, 2006
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      Power on resets in general are a PITA. A good control
      element to use for push buttons etc. is a LED/FET like
      the VACTEC VTL5C1. It's a nice package with leads in
      and leads out.

      Other FET/LED DIP packages are available from
      www.digikey.com.

      RC circuits with a schmidt trigger are the de-facto
      standard for power-on reset, but they are not
      reliable.

      I designed a really good circuit for a car, but the
      timer part doesn't exist anymore (obsoleted by
      manufacturer). 0-10 sec, very fast reset, probably
      less than 10 mS.

      The hardest part is to get good reset once the timer
      has timed out.

      I'd try a delay on make timer from SSAC combined with
      the vactrol p/n. For giggles, I'd add an LM334 and a
      diode for polarity protection. When you do this you
      get a polarity protected 3-30V DC capable 2-wire
      isolated line that needs 10 mA that you can pretty
      much do anything with.

      What you need to do, is discharge the timing element
      when the device is off (no an easy feat) and discharge
      the timing element after it's been used for timing as
      well. Again, not necessarily an easy feat.

      That CAP thing is the primary reason many devices
      don't work after a brief power failure. It takes
      $10-$15 to do it right.
      I also learned the hard way, that it depands on how
      fast the power supply powers up.

      In a microprocessor based system I worked on, if I
      used a linear supply the standard RC and gate didn't
      work. If I used a switching supply, it worked. When
      I changed to a schmidt trigger, they both worked.

      Most timers, including commercial have very crummy
      reset times on the order of 100mS. Now you know why
      they say: unplug, wait 1 minute and plug back in.
      It's probably the reason it's not in the LS - cost!



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    • Schelte Bron
      ... I would really like to keep it simple, so how about a cap and a resistor in parallel connected to ground on one side and the other side connected via a
      Message 2 of 14 , Jan 5, 2006
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        On Tuesday 03 January 2006 01:25, Derek Taubert wrote:
        > 1) When the power button is pressed, the capacitor will drain
        > directly to ground through the switch contacts. That's going
        > to be quite a zap from a 100uF cap. At minimum, I would
        > suggest putting a resistor in series with the cap (something
        > several times less resistive than whatever the weak pullup to
        > 3.3V is) and then using a smaller cap.
        >
        > 2) Applying voltage (the charged cap) to an IC input after
        > device power is removed is a great way to cause latchup and
        > permanent damage over time. Have you looked closely at this
        > trace to determine what devices are connected to it?
        >
        I would really like to keep it simple, so how about a cap and a
        resistor in parallel connected to ground on one side and the
        other side connected via a diode to the on/off button signal?

        The diode will prevent any current flowing back into the LS
        circuitry. The cap will only be able to discharge through the
        resistor. That should take care of both concerns you raised.

        I have done some experiments and it works on my LS with a 6k8
        resistor and a 22uF cap. The LS reboots if the power has been
        disconnected for as little as 3 seconds.

        Do you see any more problems with this design?

        Actually, in my experiments I found that I could get all the
        functionality I need by just shorting the switch completely.
        The LS would boot when power is applied and I could shut it
        down with the shutdown command. It doesn't seem to shutdown or
        reboot automatically at other times. I expect the disk sleep
        function will also still work. Of course the on/off button is
        completely disabled in this situation.


        Schelte.
      • KeepIt SimpleStupid
        Not knowing exactly what the LS has you can try something like wire oring. Lets try some ascii art. ***************** Ground ! ! ! ! !
        Message 3 of 14 , Jan 5, 2006
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          Not knowing exactly what the LS has you can try
          something like wire oring.

          Lets try some ascii art.

          ***************** Ground
          ! !
          ! !
          ! !
          ****** *****
          / \ / \
          ! !
          cap switch
          ! !
          ******************** To whatever needs reseting
          by a contact closure to ground

          This way either one of the signals can be interpreted
          as a
          keypress. It's just that power-up reset is
          unreliable.
          Add your resistor if you care. I'm assuming that the
          LS uses a contact closure to ground, but it doesn't
          have to be.
          PS: It's drawn upside down.

          What chip/pin is the power switch going to. Is it
          connected to anything else like a pull up or pull down
          resistor?


          --- Schelte Bron <sbron@...> wrote:

          > On Tuesday 03 January 2006 01:25, Derek Taubert
          > wrote:
          > > 1) When the power button is pressed, the capacitor
          > will drain
          > > directly to ground through the switch contacts.
          > That's going
          > > to be quite a zap from a 100uF cap. At minimum, I
          > would
          > > suggest putting a resistor in series with the cap
          > (something
          > > several times less resistive than whatever the
          > weak pullup to
          > > 3.3V is) and then using a smaller cap.
          > >
          > > 2) Applying voltage (the charged cap) to an IC
          > input after
          > > device power is removed is a great way to cause
          > latchup and
          > > permanent damage over time. Have you looked
          > closely at this
          > > trace to determine what devices are connected to
          > it?
          > >
          > I would really like to keep it simple, so how about
          > a cap and a
          > resistor in parallel connected to ground on one side
          > and the
          > other side connected via a diode to the on/off
          > button signal?
          >
          > The diode will prevent any current flowing back into
          > the LS
          > circuitry. The cap will only be able to discharge
          > through the
          > resistor. That should take care of both concerns you
          > raised.
          >
          > I have done some experiments and it works on my LS
          > with a 6k8
          > resistor and a 22uF cap. The LS reboots if the power
          > has been
          > disconnected for as little as 3 seconds.
          >
          > Do you see any more problems with this design?
          >
          > Actually, in my experiments I found that I could get
          > all the
          > functionality I need by just shorting the switch
          > completely.
          > The LS would boot when power is applied and I could
          > shut it
          > down with the shutdown command. It doesn't seem to
          > shutdown or
          > reboot automatically at other times. I expect the
          > disk sleep
          > function will also still work. Of course the on/off
          > button is
          > completely disabled in this situation.
          >
          >
          > Schelte.
          >




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        • Schelte Bron
          ... The ascii picture is a bit hard to make out, but that looks exactly like the setup I used and described on the wiki. With my more complicated proposal I m
          Message 4 of 14 , Jan 6, 2006
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            On Friday 06 January 2006 05:48, KeepIt SimpleStupid wrote:
            > Not knowing exactly what the LS has you can try
            > something like wire oring.
            >
            The ascii picture is a bit hard to make out, but that looks
            exactly like the setup I used and described on the wiki. With
            my more complicated proposal I'm trying to address the concerns
            some people raised about that first setup.

            > Add your resistor if you care. I'm assuming that the
            > LS uses a contact closure to ground, but it doesn't
            > have to be.
            >
            > What chip/pin is the power switch going to. Is it
            > connected to anything else like a pull up or pull down
            > resistor?
            >
            The LS indeed uses a contact closure to ground. I haven't been
            able to determine where the signal is going to. I lost track of
            the circuit board trace when it disappeared under the IDE
            connector. From my measurements it appears like the signal is
            pulled up with a resistance of around 7K.


            Schelte.
          • KeepIt SimpleStupid
            ... Try this on for size: Disconnect the switch from the non ground side. Label the switch point (b) and the circuit board side point (b). Connect the anodes
            Message 5 of 14 , Jan 6, 2006
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              --- Schelte Bron <sbron@...> wrote:

              > On Friday 06 January 2006 05:48, KeepIt SimpleStupid
              > wrote:
              > > Not knowing exactly what the LS has you can try
              > > something like wire oring.
              > >
              > The ascii picture is a bit hard to make out, but
              > that looks
              > exactly like the setup I used and described on the
              > wiki. With
              > my more complicated proposal I'm trying to address
              > the concerns
              > some people raised about that first setup.
              >
              > > Add your resistor if you care. I'm assuming that
              > the
              > > LS uses a contact closure to ground, but it
              > doesn't
              > > have to be.
              > >
              > > What chip/pin is the power switch going to. Is it
              > > connected to anything else like a pull up or pull
              > down
              > > resistor?
              > >
              > The LS indeed uses a contact closure to ground. I
              > haven't been
              > able to determine where the signal is going to. I
              > lost track of
              > the circuit board trace when it disappeared under
              > the IDE
              > connector. From my measurements it appears like the
              > signal is
              > pulled up with a resistance of around 7K.
              >
              >
              > Schelte.


              Try this on for size:

              Disconnect the switch from the non ground side. Label
              the switch point (b) and the circuit board side point
              (b).

              Connect the anodes of two 1n4001 diodes together and
              connect to point (b).

              Connect the cathode of one of the diodes to point (a).

              Connect the cathode of the other to your cap and the
              negative of the cap to ground.

              In this case the diodes create isolation and there is
              no issue of a cap across the switch.

              If you cannot unsolder both ends of the switch, then
              go to plan (b).

              Obtain p/n CNC1H001CT-ND from www.digi-key.com.
              Connect pins 4 and 6 across the switch. Polarity
              doesn't matter.

              Make R=(Vcc-1.2)/10mA. Vcc could be 3.3, 5 or even
              12V and pull this resistor to this voltage. Connect
              the other end of this resistor to pin #1 and a cap
              from pin 2 to ground observing polarity. Make 5 * R *
              C about equal to (0.1 to 0.5 where R is in ohms, and C
              is in Farads.

              KISS








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            • KeepIt SimpleStupid
              I was a little hasty before I replied. There is a problem with both designs. The reset time would be really bad because the charge on the capacitor would not
              Message 6 of 14 , Jan 6, 2006
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                I was a little hasty before I replied. There is a
                problem with both designs. The reset time would be
                really bad because the charge on the capacitor would
                not drain. I'd suggest a starting value of a parallel
                resistor of ten times the value of R used.

                KISS

                --- KeepIt SimpleStupid <keepitsimplestupid@...>
                wrote:

                >
                >
                > --- Schelte Bron <sbron@...> wrote:
                >
                > > On Friday 06 January 2006 05:48, KeepIt
                > SimpleStupid
                > > wrote:
                > > > Not knowing exactly what the LS has you can try
                > > > something like wire oring.
                > > >
                > > The ascii picture is a bit hard to make out, but
                > > that looks
                > > exactly like the setup I used and described on the
                > > wiki. With
                > > my more complicated proposal I'm trying to address
                > > the concerns
                > > some people raised about that first setup.
                > >
                > > > Add your resistor if you care. I'm assuming
                > that
                > > the
                > > > LS uses a contact closure to ground, but it
                > > doesn't
                > > > have to be.
                > > >
                > > > What chip/pin is the power switch going to. Is
                > it
                > > > connected to anything else like a pull up or
                > pull
                > > down
                > > > resistor?
                > > >
                > > The LS indeed uses a contact closure to ground. I
                > > haven't been
                > > able to determine where the signal is going to. I
                > > lost track of
                > > the circuit board trace when it disappeared under
                > > the IDE
                > > connector. From my measurements it appears like
                > the
                > > signal is
                > > pulled up with a resistance of around 7K.
                > >
                > >
                > > Schelte.
                >
                >
                > Try this on for size:
                >
                > Disconnect the switch from the non ground side.
                > Label
                > the switch point (b) and the circuit board side
                > point
                > (b).
                >
                > Connect the anodes of two 1n4001 diodes together and
                > connect to point (b).
                >
                > Connect the cathode of one of the diodes to point
                > (a).
                >
                > Connect the cathode of the other to your cap and the
                > negative of the cap to ground.
                >
                > In this case the diodes create isolation and there
                > is
                > no issue of a cap across the switch.
                >
                > If you cannot unsolder both ends of the switch, then
                > go to plan (b).
                >
                > Obtain p/n CNC1H001CT-ND from www.digi-key.com.
                > Connect pins 4 and 6 across the switch. Polarity
                > doesn't matter.
                >
                > Make R=(Vcc-1.2)/10mA. Vcc could be 3.3, 5 or even
                > 12V and pull this resistor to this voltage. Connect
                > the other end of this resistor to pin #1 and a cap
                > from pin 2 to ground observing polarity. Make 5 * R
                > *
                > C about equal to (0.1 to 0.5 where R is in ohms, and
                > C
                > is in Farads.
                >
                > KISS
                >
                >
                >
                >
                >
                >
                >
                >
                > __________________________________________
                > Yahoo! DSL � Something to write home about.
                > Just $16.99/mo. or less.
                > dsl.yahoo.com
                >
                >




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              • Schelte Bron
                ... Thanks for thinking along with me, but I think there s a slight miscommunication. The setup I proposed works, is about as simple as it gets and has a
                Message 7 of 14 , Jan 7, 2006
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                  On Saturday 07 January 2006 00:11, KeepIt SimpleStupid wrote:
                  > Try this on for size:
                  >
                  > Disconnect the switch from the non ground side. Label
                  > the switch point (b) and the circuit board side point
                  > (b).
                  >
                  > Connect the anodes of two 1n4001 diodes together and
                  > connect to point (b).
                  >
                  > Connect the cathode of one of the diodes to point (a).
                  >
                  > Connect the cathode of the other to your cap and the
                  > negative of the cap to ground.
                  >
                  > In this case the diodes create isolation and there is
                  > no issue of a cap across the switch.
                  >
                  > If you cannot unsolder both ends of the switch, then
                  > go to plan (b).
                  >
                  > Obtain p/n CNC1H001CT-ND from www.digi-key.com.
                  > Connect pins 4 and 6 across the switch. Polarity
                  > doesn't matter.
                  >
                  > Make R=(Vcc-1.2)/10mA. Vcc could be 3.3, 5 or even
                  > 12V and pull this resistor to this voltage. Connect
                  > the other end of this resistor to pin #1 and a cap
                  > from pin 2 to ground observing polarity. Make 5 * R *
                  > C about equal to (0.1 to 0.5 where R is in ohms, and C
                  > is in Farads.
                  >
                  Thanks for thinking along with me, but I think there's a slight
                  miscommunication. The setup I proposed works, is about as
                  simple as it gets and has a reasonable reset time (3 seconds).
                  My only question was if anyone sees any problems with that
                  design.

                  If you look at the picture I included in the wiki article you
                  will see that your plan A is not going to work because
                  unsoldering the switch cannot be done without a big risk of
                  damaging the LS.

                  Your plan B doesn't sound simpler than my proposal and I don't
                  see how it could work. The part number you mentioned is a 16
                  pin SMD 4-port opto-isolator and you seem to be using pins from
                  different ports. I assume you meant something like p/n H11F1-ND
                  or similar, but then the circuit is still more complicated than
                  mine and I don't see any advantages.

                  So unless you can point me to any dangers for the LS using my
                  setup, I'm going to go with that.


                  Thanks,
                  Schelte.
                • KeepIt SimpleStupid
                  ... Your correct with the part number that you selected. So one cap, 1 IC and 2 resistors you should have something that works and keeps the functionality of
                  Message 8 of 14 , Jan 7, 2006
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                    --- Schelte Bron <sbron@...> wrote:

                    > On Saturday 07 January 2006 00:11, KeepIt
                    > SimpleStupid wrote:
                    > > Try this on for size:
                    > >
                    > > Disconnect the switch from the non ground side.
                    > Label
                    > > the switch point (b) and the circuit board side
                    > point
                    > > (b).
                    > >
                    > > Connect the anodes of two 1n4001 diodes together
                    > and
                    > > connect to point (b).
                    > >
                    > > Connect the cathode of one of the diodes to point
                    > (a).
                    > >
                    > > Connect the cathode of the other to your cap and
                    > the
                    > > negative of the cap to ground.
                    > >
                    > > In this case the diodes create isolation and there
                    > is
                    > > no issue of a cap across the switch.
                    > >
                    > > If you cannot unsolder both ends of the switch,
                    > then
                    > > go to plan (b).
                    > >
                    > > Obtain p/n CNC1H001CT-ND from www.digi-key.com.
                    > > Connect pins 4 and 6 across the switch. Polarity
                    > > doesn't matter.
                    > >
                    > > Make R=(Vcc-1.2)/10mA. Vcc could be 3.3, 5 or
                    > even
                    > > 12V and pull this resistor to this voltage.
                    > Connect
                    > > the other end of this resistor to pin #1 and a cap
                    > > from pin 2 to ground observing polarity. Make 5 *
                    > R *
                    > > C about equal to (0.1 to 0.5 where R is in ohms,
                    > and C
                    > > is in Farads.
                    > >
                    > Thanks for thinking along with me, but I think
                    > there's a slight
                    > miscommunication. The setup I proposed works, is
                    > about as
                    > simple as it gets and has a reasonable reset time (3
                    > seconds).
                    > My only question was if anyone sees any problems
                    > with that
                    > design.
                    >
                    > If you look at the picture I included in the wiki
                    > article you
                    > will see that your plan A is not going to work
                    > because
                    > unsoldering the switch cannot be done without a big
                    > risk of
                    > damaging the LS.
                    >
                    > Your plan B doesn't sound simpler than my proposal
                    > and I don't
                    > see how it could work. The part number you mentioned
                    > is a 16
                    > pin SMD 4-port opto-isolator and you seem to be
                    > using pins from
                    > different ports. I assume you meant something like
                    > p/n H11F1-ND
                    > or similar, but then the circuit is still more
                    > complicated than
                    > mine and I don't see any advantages.
                    >
                    > So unless you can point me to any dangers for the LS
                    > using my
                    > setup, I'm going to go with that.

                    Your correct with the part number that you selected.
                    So one cap, 1 IC and 2 resistors you should have
                    something that works and keeps the functionality of
                    the button.

                    Many years ago, like 20, I used this technique to turn
                    off an audio processor when the AMP turned off. I
                    also had the ability to turn the audio system on via
                    the processors remote, Still works.
                    Weird switches (Dedicated off)
                    ON (one push -20 db, 2nd push 0 db)
                    Since the circuitry was external, isolation was
                    important,

                    Thanks for catching the errors.

                    KISS
                    >
                    >
                    > Thanks,
                    > Schelte.
                    >




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