Does anyone have a copy of the Garmin FMI specification verion 1.0 which is
applicable to the Nuvi 3xx (including 350) series?
I was looking that the FMI 2.5 spec (supported by Nuvi 12xx, 13xx, and 14xx)
and here is snippet of the specification for the Create Waypoint Protocol:
-----------------------------------------------------------------------------
typedef struct /* D607 */
{
uint16 unique_id;
map_symbol symbol;
sc_position_type posn;
uint16 cats;
uchar_t8 name[/* 31 bytes, null-terminated */];
uchar_t8 comment[/* variable length, null-terminated
string, 51 bytes max */];
} waypoint_data_type;
The unique_id is a unique identifier for the waypoint. If the specified
unique_id is already in use, then the existing waypoint will be modified
instead of creating a new waypoint.
-----------------------------------------------------------------------------
Please re-read that last sentence. It seems to me that if the OT2 is to
be compatible with FMI 2.5 devices, it needs to maintain a list of waypoint
unique_id's which can be used to update a waypoint instead of creating a
new one (breadcrumb). I doubt the Tracker2 has enough RAM to keep a long
list of waypoint ids. I wonder if anyone has a good algorithm for generating
unique 16 bit numbers given a station or object name so that maintaining
a list is not required. Since there is no perfect hash function, I wonder
if there is one that is good enough for this application? Thoughts?
--
Bob Poortinga K9SQL <http://www.linkedin.com/in/bobpoortinga>
Bloomington, Indiana US
