Re: garmin serial probe or force garmin serial mode.

[Philip Lamb]

On 31/03/2020, at 6:29 AM, Gary E. Miller <address@hidden> wrote:
> On Mon, 30 Mar 2020 16:23:46 +1300 Philip Lamb <address@hidden> wrote:
> 
>> I've got a Garmin device connected via serial link
>> and configured to report in garmin format.
> 
> And you know this how?

The device (an old Garmin Geko 301) has a menu option to set the interface 
format, and its set to “Garmin”. The serial format is locked in this mode to 
9600 8N1.

I am also able to read from the device e.g. using gpsbabel: `gpsbabel -i 
garmin,get_posn -f /dev/tty.usbserial -o kml -F mygpsposn.kml` and this works 
fine and retrieves the current fix into that kml file.

>> gpsd fails to automatically recognise the
>> format,
> 
> Which would be very odd and unusual.

>> and I see from the source at
>> https://gitlab.com/gpsd/gpsd/-/blob/master/driver_garmin.c#L1301
>> <https://gitlab.com/gpsd/gpsd/-/blob/master/driver_garmin.c#L1301>
>> that in fact no probe is implemented to detect this mode.
> 
> No probe needed.  When the Garmin sends garmin binary it is auto-detected
> in packet.c

OK, but how would a packet ever be generated if gpsd doesn’t know what protocol 
it should be using to *request* that the device start sending position data? Is 
it assumed that the device is always streaming data?

Kind regards,
Phil.