[Gta04-owner] New hw-validation snapshot

[Boudewijn]

On Friday 18 November 2011 20:57:34 Dr. H. Nikolaus Schaller wrote:
> Hi,
> 
> Am 18.11.2011 um 14:16 schrieb Boudewijn:
> > On Friday 18 November 2011 11:13:00 Christoph Mair wrote:
> > > On Fri, Nov 18, 2011 at 11:08 AM, Neil Jerram <neil at ossau.homelinux.net> 
wrote:
> > > > On 18.11.2011 09:35, Neil Jerram wrote:
> > > >> On 17.11.2011 09:35, Christoph Mair wrote:
> > > >>> Maybe its possible to boot use a initramfs to test the GPS
> > > >>> reception. This would eliminate all activities on the mmc data
> > > >>> lines.
> > > >> 
> > > >> I'm willing to try this, but I don't understand how to implement
> > > >> your suggestion.  Could you provide more detailed guidance?  (Or
> > > >> just point me to some existing reference.)
> > > > 
> > > > To be a bit more precise: I think I understand the idea of initramfs
> > > > and how to create one, but
> > > > 
> > > > (1) I can't see (looking at boot.txt) how I can tell u-boot to tell
> > > > Linux to use an initramfs
> > > > 
> > > > (2) I don't understand how this would eliminate MMC activity -
> > > > because wouldn't the kernel and initramfs still be being loaded from
> > > > the SD card?
> > > > 
> > > >  (And I believe that MMC == SD, right?)
> > > 
> > > You're right. My thought was the following:
> > > If the system is running from an initramfs the kernel won't touch the
> > > SD card. If the rootfs is on the card it may uses it for whatever
> > > reason (logging..).
> > > 
> > > Probably this could also be done with the u-boot test commands. If you
> > > have access to the serial console, enter the u-boot command prompt and
> > > type (from
> > > http://projects.goldelico.com/p/gta04-uboot/page/NewCommands) $ gps
> > > init
> > > $ gps on
> > > $ gps echo
> > For wat it's worth, I just downloaded the new kernel and configs.. Who
> > knows ;-)
> 
> I spent the afternoon comparing several of the prototype GTA04 boards
> and a GTA02. Using an external antenna glued with tape to the window's
> glass (it is a little too cold to open the window and place the antenna
> under open sky).
> Now the GTA04 boards. They all appear to be quite deaf.
> 
> After approx. 25 minutes one board (running Linux) did suddenly know the
> time.
> And some seconds later it did know the date.
> 
> Nov 18 18:52:50.645 cltest[723] NEMA: $GPRMC,185251.295,V,,,,,,,180806,,,N
> Nov 18 18:52:51.411 cltest[723] NEMA:
> $GPGGA,185252.295,,,,,0,00,,,M,0.0,M,,0000 Nov 18 18:52:51.434 cltest[723]
> NEMA: $GPGSA,A,1,,,,,,,,,,,,,,,
> Nov 18 18:52:51.481 cltest[723] NEMA: $GPRMC,185252.295,V,,,,,,,181111,,,N
> 
> Again a little later:
> 
> Nov 18 18:53:10.450 cltest[723] NEMA:
> $GPGSV,3,1,12,04,89,179,26,20,56,046,,23,48,224,,27,37,090,
> 
> indicates that Satellite #04 had SNR of 26 dB at el=89 and az=179.
> 
> Does anyone know what a "reasonable" value of SNR should be?
>
> If all EA board owners could take the challenge and do some tests?

My Phoenux has been out in the open for about 20 minutes, with power over dual 
USB (Y cable), but I think it did not find the time yet. The timestamps should 
give be near 11:25 this morning, GMT+1:

$GPGGA,002311.044,,,,,0,00,,,M,0.0,M,,0000*57
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPGSV,3,1,12,20,00,000,,10,00,000,,25,00,000,,27,00,000,*79
$GPGSV,3,2,12,19,00,000,,07,00,000,,04,00,000,,24,00,000,*76
$GPGSV,3,3,12,16,00,000,,28,00,000,,26,00,000,,29,00,000,*78
$GPRMC,002311.044,V,,,,,,,130806,,,N*40
$GPGGA,002312.032,,,,,0,00,,,M,0.0,M,,0000*55
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPRMC,002312.032,V,,,,,,,130806,,,N*42
$GPGGA,002313.032,,,,,0,00,,,M,0.0,M,,0000*54
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPRMC,002313.032,V,,,,,,,130806,,,N*43
$GPGGA,002314.042,,,,,0,00,,,M,0.0,M,,0000*54
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPRMC,002314.042,V,,,,,,,130806,,,N*43
$GPGGA,002315.032,,,,,0,00,,,M,0.0,M,,0000*52
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPRMC,002315.032,V,,,,,,,130806,,,N*45
$GPGGA,002316.032,,,,,0,00,,,M,0.0,M,,0000*51
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPGSV,3,1,12,20,00,000,,10,00,000,,25,00,000,,27,00,000,*79
$GPGSV,3,2,12,19,00,000,,07,00,000,,04,00,000,,24,00,000,*76
$GPGSV,3,3,12,16,00,000,,28,00,000,,26,00,000,,29,00,000,*78
$GPRMC,002316.032,V,,,,,,,130806,,,N*46

I'll let it next to the window (on the inside) for the next few hours.

Boudewijn
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