Re: [gpsd-users] Sending SiRF commands to GPS receiver

[Alexander Carver]

On 2/26/2012 11:43, Eric S. Raymond wrote:
> Alexander Carver<address@hidden>:
> > Right, I understand that much but what should the format of the
> > command be after -x because it's not documented for SiRF.  The
> > manpage for gpsctl lists UBX, Navcom NCT, Trimble TSIP, Zodiac, and
> > straight NMEA but it leaves out SiRF.
>
> I don't see that the man page documents any formats at all.  What text
> are you speaking of?  Would you quote it, please?  I want to make sure
> we're not talking past each other.


Sure thing:

-x

    Send a specified control string to the GPS; 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. (You must include the leading $ for NMEA packets.) When 
sending to a UBX device, the first two bytes of the string supplied will 
become the message class and type, and the remainder the payload. When 
sending to a Navcom NCT or Trimble TSIP device, the first byte is 
interpreted as the command ID and the rest as payload. When sending to a 
Zodiac device, the first two bytes are used as a message ID of type 
little-endian short, and the remainder as payload in byte pairs 
interpreted as little-endian short. C-style backslash escapes in the 
string, notably \xNN for hex, will be interpreted; additionally, \e will 
be replaced with ESC. This switch implies -f.




While it doesn't lay out the format explicitly as a full command line 
example, it does document what bytes go where and what may be needed for 
each one including which bytes should appear first.  It just happens to 
leave out SiRF.