Checksum Help?
I am having problems getting my basic stamp to read the serial in from my Garmin GPS. I am trying to use the @ symbol as the checksum but when I put in any checksum into my code the program locks up. Here is my code I am trying to use.
Adam
Adam
Comments
I know that the Parallax GPS uses "*" as the marker for the checksum. I think that's pretty standard.
Post Edited (autobus83) : 3/17/2008 12:24:37 AM GMT
As you can tell from that, the initial character of a data item is "$", not "@". Do make sure that you have the Baud mode
constant correct for your GPS receiver. Check the SERIN chapter in the Parallax Basic Stamp Manual for the proper connections
and the proper Baud mode constant. The Garmin receiver puts out RS232 signals and the Baud mode should be for inverted data.
SERIN 0, 16572, 2100, No_Data, [noparse][[/noparse]WAIT("$"),gpstime]
16572 should be 4800 baud inverted. It is really jumpy and when it does show me the value of gps time it is a funky letter y,
th kind you see when the baud is not set correctly.
I checked and the baud on my gps is set to 4800.
The BS2 Stamp value is 188 for 4800 non inverted
The Parallax receiver uses 4800 non baud inverted, as do most Garmin units.
A good reference for GPS NEMA info is at www.gpsinformation.org/dale/nmea.htm
phil
Post Edited (phil kenny) : 3/17/2008 3:41:44 AM GMT
SERIN 0, 16572, 2100, No_Data, [noparse][[/noparse]WAIT("$"),STR gpstime\8]
Use a DEBUG to see what was captured.
Cheers,
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Tom Sisk
http://www.siskconsult.com
·
It goes --·$GPRMC,hhmmss.sss, other stuff...
If all you want is the hours, minutes, and seconds:
Post Edit --·If 16572 doesn't work, try 188.· I don't know the details of your·Stamp-to-Garmin inter-connect.
Post Edited (PJ Allen) : 3/24/2008 2:48:14 AM GMT