Re: [gpsd-users] control ublox-M8 by gpsctl

[Yunchuan Geng]

Hi,


Thanks Gary.


On 04/01/2015 10:50 PM, Gary E. Miller wrote:
> I playedd with this a bit, on 3.15-dev.
>
> -x requires direct access, so I was wrong to say start gpsd first.
In fact, gpsd is autostarted from system config when the linux bootup.
> -t is not required, auto detect works fine.o
auto detect match NMEA0183 for me.
> I ended up with this string:
>
> gpsctl  -D 5 -x  "\xB5\x62\x06\x04\x04\x00\xFF\x87\x00\x00\x94\xF5" /dev/ttymxc2
>
> Which works just fine at sending the hex string to the GPS.
>
> Sadly it never waits for the answer...
For this command, it looks like you are playing a reset to M8.
I checked the ProtocolSpec of M8 about this command. It says:

Don't expect this message to be acknowledged by the receiver.
       • Newer FW version won't acknowledge this message at all.
        • Older FW version will acknowledge this message but the 
acknowledge may not be sent
         completely before the receiver is reset

Maybe it is ok without anwser.

Another question or confirmation about gpsctl command itself. According 
to the man page of gpsctl of ubuntu
http://manpages.ubuntu.com/manpages/lucid/man1/gpsctl.1.html

It says "gpsctl will provide packet headers and trailers and checksum as 
appropriate for binary packet types, and whatever checksum and trailer 
is required for text packet types", which means we do not need to feed 
header and checksum with -x option. but you did. Is it really necessary 
or not?


Best regards,
Yunchuan