[arm-allstar] Power cycle USB

[Doug Crompton]

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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