[Loadstone] Success at last (I think!)

Aedan O'Meara aomeara at iol.ie
Wed Dec 20 11:30:11 GMT 2006

Hi Monty and Shawn and all,
I carefully went over the Sirfdemo program again and studied Rob's tutorials
again as well. I am now getting speed reports on occasion by swinging the
gps around at arm lenght of 2kph which makes me think I have disabled SN at
last. I am in bed with flu for last few days so cannot test it on road yet,
but it looks good.
As the procedure is so complex I carefully wrote it all down in Notepad and
I submit it here for the benefit of others in a similar situation.
Happy Christmas and prosperous New Year to all on this list.

Tutorial for using Sirfdemo with Holux slim 236 and data cable.

by Aedan O'Meara.
Install mini disk that comes with Holux gps.
1. using data cable. Connect cable and attach Holux gps. Turn it on.
2. Open Sirfdemo and you will be put into the setup menu.
3. Select serial port option
Select the com number. This may be found in Device manager but will also be
displayed here with all other live com
The connecting baud rate will be displayed
Untick "Use aux(auxillary) data source"
press ok
4. Under Setup choose Target s/w(software) version choose v3.0/3.1
Leave auto on.
press ok
5. Under Actions click on open data source.
Visually as you are in nmea protocol you should have data streaming in only
Debug window. This is normal,
see note below.

6. Under Actions you should have switch to Sirf protocol as the only option
Click this.
Data streams will change and all windows will be filled. Under actions the
highlight should move to Switch to
nmea protocol.
Switch to Sirf protocol should be greyed out.
If this doesn't happen you have not successfully gone into Sirf protocol.

 Never play with user protocol because if you put the GPS into this without
a third party protocol in the GPS
you will loose all communication with the GPS.
Also never synchronize the protocol and baud rate as this might put the GPS
baud rate out of reach particularly
under bluetooth connection.

	7. Now under Navigation go to Static Navigation.
opening this will give a current window and the ticked option is the
current  one set in the GpS, although Carl says differently, see note below.
Select disable and highlight and click send.
I notice that this message is sent at 57,600 baud.
No wonder it doesn't work at the fixed 38,400 baud on bluetooth!

8. Now return gps to nmea protocol by clicking on this under Actions.
This will open a list box.
The default baud rate offered in here is 9600.
As Sirfdemo pulls the gps to its own baud you can change to nmea at 9600
successfully but you will not
then be able to use your bluetooth connection to
Loadstone as this is at 38,400.
Alter baud rate here to 38,400 to restore the gps to Bluetooth rate,
otherwise when you  connect to bluetooth gps
in Loadstone you will get the
message "gps clock has  stopped ticking, disconnecting" after about 5 secs.
( this is because the baud rate has been left at 9600 and the bluetooth baud
rate is 38,400.). You will still be
able to connect repeatedly at the bluetooth
See note below about setting VTG to 1 sometimes. It is default here at 0.

Finally click on the Send button to finish.

Exit Sirfdemo.

Your Holux slim 236 should now be working properly with the SN turned off.

Selected Notes from Rob's tutorial list:
Answer to question about the other settings in the switch to nmea list box:
The values you put there are the message output rates in seconds between
outputs, and should be set to output the specific messages you require (or
mapping program needs). The default settings are 1 second for GGA, GSA and
RMC, and 5 seconds for GSV. If you want velocity and heading, you can put 1
second for VTG. GLL is available as an alternative to GGA. Set values only
for the messages you want. Note that the ??? entries are for messages a
may add as an extra. Most do not add any, although some SiRF receivers
support the ZDA (time and date) message in the middle of the 3 spots.

For NMEA mode, SiRFDemo only displays the messages in the Debug View window
and does not provide information in the other windows. That is normal for
program. The program is designed only to demonstrate receivers, so it has
some features only implemented with SiRF binary format. And since NMEA
is a universal protocol, it does not define functions to do many settings
that are unique to a specific receiver. We implemented a few features in
(such as changing to SiRF protocol, changing message rates, etc.), but not
the others. To make those changes you must switch to binary mode, make the
and then switch back to NMEA.

Carl - SiRF Customer Support

I just bought a GlobalSat BT-338. When I connect it to my PC with a BT
dongle and start the SiRFDemo 3.61 I get a lot of 'Bad parity from SV xx,
x'. For the rest the BT-338 seems to work.

Is this a software problem or is there really something wrong with the GPS?

Thanks for the answer. And if this question has already been answered, I did
not find it.

Reply author: gpspassion
Replied on: 07/25/2005 15:26:04

Welcome to the forums.
Sounds like you're using the wrong baudrate, make sure you select 38,400bps.


Reply author: Carl at SiRF
Replied on: 07/26/2005 23:58:02

Actually, I think his baud rate was set just fine. That particular error
message means that he probably locked onto the satellites in the middle of a
of the navigation message. As a result he found a parity error (since he
received the correct parity bits, but not all the actual data bits). This is
very normal and common error when you see it at startup. Other than that,
you generally only see it when you have an actual parity error (pretty rare)
or when you have a blockage and come out of it (same reason as when you see
it at startup).

(Happens when you go into invisible cursor or Jaws cursor and when switching
back to nmea protocol, Aedan.)
Carl - SiRF Customer Support

Synchronize Protocol and Baud Rate actually only sends a command to the
receiver to go to SiRF protocol, and it does it at every baud rate and in
both SiRF
and NMEA protocol. Then it switches to SiRF protocol at 57600 where it
expects to find the receiver. If that doesn't work for you, it is probably
the receiver is set up to communicate at a different baud rate (e.g., 38400
for many Bluetooth receivers). If Synch doesn't work for you, after you have
tried it scan each baud rate manually, starting at 4800 and working upwards
to 115200. Assuming you find the receiver at one of them, remember that as
your receiver is likely to go there whenever it is told to change protocol.

SiRFDemo is not a passive program like many monitors -- it often sends
commands to the receiver when you aren't expecting it to. For example, if
you open
a log file, SiRFDemo sends a query for software version and navigation
settings to the receiver and logs the results in the log file so that
is available when the file is reviewed. Likewise, if you try to issue a
command to change some setting like static navigation, SiRFDemo queries the
to find the current setting, and if it is successful then the menu you see
will have the option already set for you (I think that one sets the option
that if you just click "send" it will change the current setting -- for
example, if static nav is off, it will show the default as "on" so if you
"send" it will change the setting).

For your current case, scan until you find where the receiver is talking,
then command it back to NMEA at the right baud rate and you should be fine.

Carl - SiRF Customer Support

More information about the Loadstone mailing list