GPS and BS2P

Archiver

Perhaps it was Mr. Williams, but someone said they had code for reading a
sentence from a GPS reciever and storing it in the scratch pad RAM of the
BS2P. I assume it is a series of reads and puts. Is there a benefit for
storing GPS data into the scratch pad? I'd still need to define varaibles
in RAM to get the fragments of data in the GPS sentence.

Paul

Archiver

I would be very interested in any information regarding interfacing a
GPS receiver to a BS2/BS2SX. I have a DeLORME TripMate. I don't
even know where to begin. Pinouts, circuit diagrams, code, etc.

Thanks,
Brice

> Perhaps it was Mr. Williams, but someone said they had code for
reading a
> sentence from a GPS reciever and storing it in the scratch pad RAM
of the
> BS2P. I assume it is a series of reads and puts. Is there a
benefit for
> storing GPS data into the scratch pad? I'd still need to define
varaibles
> in RAM to get the fragments of data in the GPS sentence.
>
> Paul
>
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
>
>

Archiver

> I would be very interested in any information regarding interfacing a
> GPS receiver to a BS2/BS2SX. I have a DeLORME TripMate. I don't
> even know where to begin. Pinouts, circuit diagrams, code, etc.
>
> Thanks,
> Brice

GPS data follows a standard set up by NMEA. It's serial data at 4800 baud,
N81. Once the tripmate starts up, it will send sentneces at 1 second
intervals, as I recall. You'll want the GGA and RMC sentence, and they will
begin as $GPGGA,..... and $GPRMC,........ The GGA sentence gives the time,
lat, long, and altitude data along with number of satellites, etc. From the
RMC sentence you'll get the time, speed, and heading.

Paul

Archiver

Thanks. That should get me started... Do you have an example of
code for the SERIN commands? Are any commands sent to the receiver
or once it aquires the satellites, does it just start sending data?

- Brice

> > I would be very interested in any information regarding
interfacing a
> > GPS receiver to a BS2/BS2SX. I have a DeLORME TripMate. I don't
> > even know where to begin. Pinouts, circuit diagrams, code, etc.
> >
> > Thanks,
> > Brice
>
> GPS data follows a standard set up by NMEA. It's serial data at
4800 baud,
> N81. Once the tripmate starts up, it will send sentneces at 1
second
> intervals, as I recall. You'll want the GGA and RMC sentence, and
they will
> begin as $GPGGA,..... and $GPRMC,........ The GGA sentence gives
the time,
> lat, long, and altitude data along with number of satellites, etc.
From the
> RMC sentence you'll get the time, speed, and heading.
>
> Paul
>
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
>
>

Archiver

[font=arial,helvetica]In a message dated 3/7/01 8:17:06 AM Central Standard Time,
pverhage@sd131.k12.id.us writes:

Perhaps it was Mr. Williams, but someone said they had code for reading a
sentence from a GPS reciever and storing it in the scratch pad RAM of the
BS2P. ·I assume it is a series of reads and puts. ·Is there a benefit for
storing GPS data into the scratch pad? ·I'd still need to define varaibles
in RAM to get the fragments of data in the GPS sentence.

I didn't say it (and you can call me Jon), but I will be working on this as I
just bought a GPS receiver for a demo.

The advantage of using the SPSTR parameter in SERIN is that is just dumps
everything the scratchpad. ·When using SKIP, the extra processing time will
occasionally cause lost characters (despends on SERIN speed). ·By simply
dumping everything to RAM then reading it after (yes, with GET), there are
fewer opportunities for lost data.

As far as your other scratchpad data, start at byte 126 (highest use byte)
and work your way down from there. ·So, you write at one end of the RAM, the
SPSTR writes at the other. ·I've adopted this stardard (PUTting my data at
the high end of RAM) so that I can use SPSTR with SERIN, OWIN and I2CIN.

Like I said, I just bought a GPS receiver and will be connecting it to my
BS2p shortly. ·I'm sure my demo code will be posted at Parallax and may even
show up in a Nuts & Volts article.

-- Jon Williams
-- Dallas, TX[/font]

Archiver

> Thanks. That should get me started... Do you have an example of
> code for the SERIN commands? Are any commands sent to the receiver
> or once it aquires the satellites, does it just start sending data?

The Tripmate needs the ASTRAL command to start sending data. There's a way
to trick the Tripmate by connecting two wires, so the Tripmate sees it's own
ASTRAL command. I'll see if I can dig that back up.

Paul

Archiver

Check out the following site for more infomation on GPS commands and how they
work.

http://joe.mehaffey.com

Bruce Snowden