I am trying to write a sketch that will eventually print lat and lon to a 2x16 lCD but for now I am just printing to the debug port. I am using NMEA_isr.ino as a starting point with a few mods. So far I am unable to access any of the fix data in my sketch. I started by trying to simply print latitude to the debug serial port after trace_all does it’s thing in loop(). The printout from trace_all is good but my new line of code only prints out zero.
I tried a similar approach with modifications to NMEA.ino and in that sketch I am able access the fix data and print it as I desire. But I really want to use the interrupt.
Here is what I did to NMEA_isr.ino to try and make this work:
I added one line after static NMEAGPS gps; as follows:
static NMEAGPS gps;
static gps_fix fix_data;
and in loop() I added 2 lines after trace_all as follows:
trace_all( DEBUG_PORT, gps, gps.read() );
fix_data = gps.read();
DEBUG_PORT.println(fix_data.latitudeL());
I obviously don’t understand something fundamental here, but if someone can point me in the right direction on this I would sure appreciate it.
Here is the modified NMEA_isr.ino
#include <Arduino.h>
#include "NMEAGPS.h"
//======================================================================
// Program: NMEA_isr1.ino
//
// Prerequisites:
// 1) NMEA.ino works with your device
//
// Description: This minimal program parses the GPS data during the
// RX character interrupt. The ISR passes the character to
// the GPS object for parsing. The GPS object will add gps_fix
// structures to a buffer that can be later read() by loop().
//======================================================================
#if defined( UBRR1H )
// Default is to use NeoSerial1 when available. You could also
#include <NeoHWSerial.h>
// NOTE: There is an issue with IDEs before 1.6.6. The above include
// must be commented out for non-Mega boards, even though it is
// conditionally included. If you are using an earlier IDEs,
// comment the above include.
#else
// Only one serial port is available, uncomment one of the following:
//#include <NeoICSerial.h>
#include <NeoSWSerial.h>
//#include <SoftwareSerial.h> /* NOT RECOMMENDED */
#endif
#define RX_PIN 2
#define TX_PIN 3
#include "GPSport.h"
#include "Streamers.h"
#ifdef NeoHWSerial_h
#define DEBUG_PORT NeoSerial
#else
#define DEBUG_PORT Serial
#endif
// Check configuration
#ifndef NMEAGPS_INTERRUPT_PROCESSING
#error You must define NMEAGPS_INTERRUPT_PROCESSING in NMEAGPS_cfg.h!
#endif
static NMEAGPS gps;
static gps_fix fix_data;
//--------------------------
static void GPSisr( uint8_t c )
{
gps.handle( c );
} // GPSisr
//--------------------------
void setup()
{
// Start the normal trace output
DEBUG_PORT.begin(9600);
while (!DEBUG_PORT)
;
DEBUG_PORT.print( F("NMEA_isr1.INO: started\n") );
DEBUG_PORT.print( F("fix object size = ") );
DEBUG_PORT.println( sizeof(gps.fix()) );
DEBUG_PORT.print( F("NMEAGPS object size = ") );
DEBUG_PORT.println( sizeof(gps) );
DEBUG_PORT.println( F("Looking for GPS device on " USING_GPS_PORT) );
trace_header( DEBUG_PORT );
DEBUG_PORT.flush();
// Start the UART for the GPS device
gps_port.attachInterrupt( GPSisr );
gps_port.begin( 9600 );
}
//--------------------------
void loop()
{
while (gps.available()) {
// Print all the things!
trace_all( DEBUG_PORT, gps, gps.read() );
fix_data = gps.read();
DEBUG_PORT.println(fix_data.latitudeL());
}
if (gps.overrun()) {
gps.overrun( false );
DEBUG_PORT.println( F("DATA OVERRUN: took too long to use gps.read() data!") );
}
}
