NMEA data capture to SD card

Mike Cook · 2007-01-13 15:06

Here is a simple little application to demonstrate Tom Rokicki's SD object.

1. Captures data from a GPS receiver attached to P16 of the Propeller and writes this data to a SD card.

2. SD card is installed on P0..3,

3. TV is installed on P12..15 (same as Propeller Demo Board)

4. Push button switch on P4

I'm using a Trimble IQ receiver that has a MAX-232 installed, so I have another MAX-232 that converts it back to TTL to go to P16 of the Propeller chip. To use the Parallax GPS receiver, just configure it for RAW output and connect the serial output directly to P16 of the Propeller.

The program waits for the user to press a button attached to P4 of the Propeller, then waits for the '$' which indicates the beginning of a NMEA sentence. After that it will capture the NMEA sentences to the SD card. When your ready to stop capturing data then press the button. The program will wait for the line feed character (end of the NMEA sentence), close the file, and then it's safe to remove the SD card.

1. GPS receiver is configured for 4800,8,N,1

2. The archive includes a modified version of fsrw.spin, but the original file in the SD object will work just fine. My version·has a 'File Time Stamp' routine that's not used in this program.

3. Includes a modified version of FullDuplexSerial.spin. I increased the RX buffer to insure there would be no data loss at 4800,8,N,1

4. Archive includes the v1.02 version of the Propeller Tool, just incase.

Still learning SPIN so my 'logic' may not be 'tight' as is could be, but each line is commented so it should be self explanatory.

Though I would post this for anyone doing something similar. Have Fun!

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Mike

Post Edited (Mike Cook) : 1/13/2007 3:25:32 PM GMT