[time-nuts] Re: 2nd Run of TimeHats

[Graham / KE9H]

Put me down for one.
--- Graham     ke9h.graham (at) gmail.com

On Mon, Apr 26, 2021 at 2:51 PM James Perkins <james at loowit.net> wrote:

> Interested in 1 for comparison with my existing setups.
>
> I have an adafruit ultimate GPS hat, a Deegoo GT-7U GPS module board, and
> I've been interfacing these with Raspberry Pi 4B and AVNET's MaaXBoard
> IMX8M to compare responsiveness, using gpsd and chrony. The Pi claims very
> stable operation, RMS Offset ~1us, Skew ~0.030 ppm. The MaaXBoard, even
> with identical GPS attached, runs with ~90us RMS Offset, Skew ~4.7 ppm. I'm
> suspecting the MaaXBoard's sampling of the PPS GPIO is low-frequency,
> interrupt latency is large, its system clock is low resolution, or it is in
> some sort of idle deep sleep mode that takes it a long time to recover
> from, but I'm going to need to look into it more deeply, and that's why the
> oscilloscope just arrived. I'd like the MaaXBoard to work because of the
> IMX8's IEEE 1588 PTPv2 Ethernet MAC, but there are alternatives in this
> price range like Atmel SAMA5D3.
>
> Cheers,
> James
>
> On Mon, Apr 26, 2021 at 9:57 AM John Miller via time-nuts <
> time-nuts at lists.febo.com> wrote:
>
> > Hello everyone,
> >
> > I’ve seen a number of messages lately that reference the TimeHat boards I
> > put together a couple of months ago, with lots of positive feedback,
> which
> > I really appreciate. The first run of boards I did sold fairly quickly,
> and
> > based on a number of emails I have gotten lately there seems to be some
> > renewed interest.
> >
> > As such, I’m going to order up another batch of PCBs and parts, but I’d
> > like to get an idea of how many I need to order to satisfy current
> demand.
> > The GPS modules come from China, so there is about a two or three week
> wait
> > them, so I want to make sure I have enough.
> >
> > For those not familiar, you can learn more about the TimeHat here:
> > https://millerjs.org/timehat
> >
> > Regards,
> > John
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>
>
> --
> James Perkins <james at loowit.net>  KN1X  www.loowit.net/~james
> 2030 W 28th Ave, Eugene OR 97405       +1.971.344.3969 mobile
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