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Re: [gpsd-dev] GR-701W hangs on Pi-3
From: |
Gary E. Miller |
Subject: |
Re: [gpsd-dev] GR-701W hangs on Pi-3 |
Date: |
Fri, 3 Jun 2016 00:43:17 -0700 |
Yo Hal!
On Thu, 02 Jun 2016 22:30:23 -0700
Hal Murray <address@hidden> wrote:
> address@hidden said:
> > Do you trust your power? The Pi 3 is even more picky than the Pi
> > 2.
>
> Thanks. That could be the problem. Meter says 4.8V. I didn't get
> out a scope to look for dips below that.
I have heard that 4.8 is about as low as you can expect a Pi to fully
function.
> address@hidden said:
> > Everyone should have a USB V/A meter, they are cheap. Here is one
> > for $6:
>
> Beware. Inserting a current meter will actually drop the voltage you
> get. You should probably get a real meter to see if the USB meter is
> showing the high side or low side of the current measuring resistor.
And what do you call a 'real' meter?
Any modern meter should have a really, really, small drop resistor.
But, a good question. I'll open up a few of my meters to check.
> > The Pi people say 2 amps is not good enough, they recommend 2.5A.
>
> That depends upon the stuff you plug into your Pi. With a regulated
> supply, it doesn't help to have one with a higher current rating. It
> might run cooler.
Yes, but overkill in a power supply is always a good thing.
> In theory, each USB port can ask for 500 mA. I don't know how much
> the Pi will give out. Then you can plug in a HAT...
Yup. The Pi has 4 ports, that is 2 A right there!
Too much to think about, that is why I use the meters.
> Adafruit says their wall wart style power supplies targeted at the Pi
> actually set the output voltage at 5.25 to give a little more room
> after the end of the cable.
Good idea. And the Qualcom Quick Charge go up to 9V, and more.
> > 28AWG is 0.064 ohms per foot. Double that for out and back to
> > 0.128 ohms/ft of USB cable.
>
> 0.128 * 3 * 0.7 is 0.268 V. So if you start with 5V, you will be
> under 4.8.
>
> Adafruit also has 6 inch cables. :)
I like my Tronsmart 20AWG cables, and I keep them as short as I can.
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
address@hidden Tel:+1 541 382 8588
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- Re: [gpsd-dev] GR-701W hangs on Pi-3, (continued)
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Gary E. Miller, 2016/06/02
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Eric S. Raymond, 2016/06/03
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Hal Murray, 2016/06/03
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Frank Nicholas, 2016/06/03
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Eric S. Raymond, 2016/06/03
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Gary E. Miller, 2016/06/03
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Gary E. Miller, 2016/06/02
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Frank Nicholas, 2016/06/03
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Gary E. Miller, 2016/06/03
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Hal Murray, 2016/06/03
- Re: [gpsd-dev] GR-701W hangs on Pi-3,
Gary E. Miller <=
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Hal Murray, 2016/06/03
- Re: [gpsd-dev] GR-701W hangs on Pi-3, Gary E. Miller, 2016/06/03
Re: [gpsd-dev] GR-701W hangs on Pi-3, Eric S. Raymond, 2016/06/02