[arm-allstar] Power cycle USB

Thu Feb 21 13:18:41 EST 2019

 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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> > >
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