[arm-allstar] Power cycle USB

Thu Feb 21 15:42:19 EST 2019

OK, now I understand and I am glad you found a solution. By human nature
when these kind of things happen and you lose a lot of equipment you go
overboard in doing things you think will correct it. In my mind bonding
might be more important in this situation than isolation. Heavy grounds
between all items in addition to the existing signal grounds. You also
could isolate if necessary on the audio side instead of of the FOB instead
of USB with transformers on the audio and opto isolators on the COS and PTT.

*73 Doug*

*WA3DSP*

*http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*

On Thu, Feb 21, 2019 at 3:34 PM "Roger Coudé via ARM-allstar" <
arm-allstar at hamvoip.org> wrote:

> Doug,
>
> Those USB isolators are based on the ADuM4160 chip and are sold with a 5V
> isolated dc-dc (as per the link I sent before)
>
> So, for sure, one side of the chip is connected to the input of the dc-dc
> and the other side on the ouput, providing 1500 volts galvanic isolation.
>
> I did some tests and found that if I insert a non-powered usb hub between
> the isolator and the FOB, everything works fine.
>
> Looks like the hub added some delay and it solved the problem.
>
> Those isolators are popular in the audio world to prevent ground loops
> between audio devices
>
> I did the test on a WIndows machine and I have exactly the same behavior:
> the device is lost after reboot.
>
> Inserting a non-powered USB Hub also solved the problem.
> I dont want you to lose time on that, I was just asking the recipy to
> perform a USB cycle outside your application.
> 73
> Roger
> VE2DBE
>
>
>
>
> Le jeudi 21 février 2019 14 h 18 min 52 s HNE, Doug Crompton via
> ARM-allstar <arm-allstar at hamvoip.org> a écrit :
>
>
>
>
>
> Roger,
>
> The chip you are using has a vbus1 and a vbus2  pins 1 and 16.  Do you
> connect them together and power from the USB 5V supply? I am just trying to
> figure out why this is happening. I find it hard to  believe it has
> anything to do with Linux or the sound card.
>
> What if you plugged it into a Windows box and ran sound to the FOB. Would
> it do the same thing?
>
>
> *73 Doug*
>
> *WA3DSP*
>
> *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
>
>
> On Thu, Feb 21, 2019 at 2:10 PM "Roger Coudé via ARM-allstar" <
> arm-allstar at hamvoip.org> wrote:
>
> >  It is a 5V isolated DC-DCThere are many flavors with the same chipset:
> >
> https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR3.TRC1.A0.H0.Xusb+isolator.TRS0&_nkw=usb+isolators&_sacat=0Roger
> >
> >    Le jeudi 21 février 2019 12 h 00 min 43 s HNE, Doug Crompton via
> > ARM-allstar <arm-allstar at hamvoip.org> a écrit :
> >
> >  Roger,
> >
> >  Referring to this data sheet -
> >
> >
> >
> https://www.analog.com/media/en/technical-documentation/data-sheets/adum4160.pdf
> >
> > It appears there are multiple ways to configure power. How are you
> powering
> > the adum4166?
> >
> > It can get power directly from the Pi source or via USB.  This chip has
> > isolation but if both the Pi side and the FOB side are running from the
> > same power supply is there really isolation? There would be common ground
> > and power.
> >
> >
> > *73 Doug*
> >
> > *WA3DSP*
> >
> > *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
> >
> > On Thu, Feb 21, 2019 at 10:56 AM "Roger Coudé via ARM-allstar" <
> > arm-allstar at hamvoip.org> wrote:
> >
> > >  Doug, not sure that would change anything. I tested with two sound
> > cards,
> > > one directly connected, the other is via the usb isolator. If I do
> lsusb
> > > after reboot only one shows up. If I unplug an reconnect the second usb
> > > card, lsusb detects both, an asterisk is happy. I will try more testing
> > > later today. USB isolation is less trouble than using audio transfo and
> > > optocouplers. It is by far the easiest solution to use with rim lite. I
> > do
> > > not think asterisk is in fault here, more a linux issue. The reason for
> > my
> > > first message. 73 Roger ve2dbe
> > >
> > >    Le jeudi 21 février 2019 10:22:24 UTC−5, Doug Crompton via
> ARM-allstar
> > > <arm-allstar at hamvoip.org> a écrit :
> > >
> > >  Roger,
> > >
> > >  I am still not clear on how turning off the USB power would help. This
> > > would turn off the power to both the isolator and the sound card and
> then
> > > they would come up the same way they do at boot. Am I missing
> something?
> > > You say some sound cards? Do some work and not others? At boot power is
> > > supplied to the USB interface later in the boot process. Then Asterisk
> is
> > > started and the sound card is detected. You can delay the start of
> > Asterisk
> > > in /usr/local/etc/allstar.env.  The parameter in there is START_DELAY
> It
> > > is =0 by default.  Perhaps setting it to say =5  for 5 seconds might do
> > > what you want to do?
> > >
> > >
> > > *73 Doug*
> > >
> > > *WA3DSP*
> > >
> > > *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
> > >
> > >
> > > On Thu, Feb 21, 2019 at 9:56 AM "Roger Coudé via ARM-allstar" <
> > > arm-allstar at hamvoip.org> wrote:
> > >
> > > > Doug,
> > > > The USB isoltor is based on the ADUM4160
> > > > A small DC-DC isolates the 5V
> > > > I am not sure if the change in the kernel did it, but the sound card
> is
> > > > not detected at reboot.
> > > > It looks like the ADUM4160 should be powered before the sound card to
> > > > insure proper detection.
> > > > It probably has to do with the hand shaking between the device and
> the
> > > > computer.
> > > > I have a hardware solution with two transistors and a capacitor that
> > > > forces a delay before the sound card is powered.
> > > > Another hardware solution is to use a relay to cut the power to the
> > sound
> > > > card with gpio.
> > > > But I consider a software solution would be more elegant...
> > > > 73
> > > > Roger
> > > > VE2DBE
> > > >
> > > > ----------------
> > > >
> > > > Roger,
> > > >
> > > > The USB power cycle on the Pi is unreliable and operates differently
> > and
> > > > inconsistently on different Pi models. Thus we removed it because it
> > > didn't
> > > > work in some situations and actually caused the Pi to crash in
> others.
> > > The
> > > > reasoning was that a reboot does the same thing. At boot power to the
> > Pi
> > > is
> > > > shutoff until it activates the USB.  This is typically several -
> maybe
> > > 4-5
> > > > seconds after boot. I am not sure what is ramping up but that should
> > > > certainly be enough time for anything to stabilize. Are you sure that
> > is
> > > > the problem?
> > > >
> > > >
> > > > *73 Doug*
> > > >
> > > > *WA3DSP*
> > > >
> > > > *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio
> >*
> > > >
> > > >
> > > > On Wed, Feb 20, 2019 at 9:59 PM "Roger Coudé via ARM-allstar" <
> > > > arm-allstar at hamvoip.org> wrote:
> > > >
> > > > > One of the mountain top repeater we have had a major ground fault
> > after
> > > > an
> > > > > ice storm.
> > > > > Almost all equipement, including commercial and amateur was heavily
> > > > > damaged.
> > > > > We replaced all equipement and added galvanic isolation in order to
> > > > > protect the RPI from possible ground fault from the radio.
> > > > > A simple solution was to use usb isolators and it did the trick.
> > > > > However, these components sometimes introduce a voltage ramp up and
> > > some
> > > > > sound cards are not recognized after reboot.
> > > > > That was easily solved by using the usb power cycle in admin menu,
> > > since
> > > > > the dc-dc does not have ramp up when already powered.
> > > > > Now that function has been removed and we have to wait next summer
> to
> > > go
> > > > > to the site and power cycle the sound card manually.
> > > > > Is there a script or command we can use aside to get that usb power
> > > cycle
> > > > > back?
> > > > > 73
> > > > > Roger
> > > > > VE2DBE
> > > >
> > > > >
> > > > >
> > > > > _______________________________________________
> > > > >
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> > > > > ARM-allstar at hamvoip.org
> > > > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > > > >
> > > > > Visit the BBB and RPi2/3 web page - http://hamvoip.org
>
> > > > _______________________________________________
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> > > >
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> > > >
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> >
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> >
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> >
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>
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