Arduino GPS code question

Projects Programming
1

hello i've tested an arduino code using TinyGPS library and its working however i do not know why one of the functions is used, can someone tell me?

#include <TinyGPS.h>

TinyGPS gps;
static void gpsdump(TinyGPS &gps);
static bool feedgps();

void setup()
{Serial.begin(9600);}

void loop()
{bool newdata = false;
  unsigned long start = millis();
  while (millis() - start < 5000)
  {if (feedgps())
      newdata = true;
  }
 gpsdump(gps);
}

static void gpsdump(TinyGPS &gps)
{float flat, flon;
  gps.f_get_position(&flat, &flon);
  Serial.print(flat);
  Serial.println(flon);
}
static bool feedgps()
{
  while (Serial.available())
  {if (gps.encode(Serial.read()))
      return true; }
  return false;
}

for what is feedGPS used? in the while loop of delay theres a condition there with feedgps whats its importance? and what does the return value do?
thanks

2

Have you consulted the documentation?

3

aarg:
Have you consulted the documentation?

Feed the object serial NMEA data one character at a time using the encode() method. (TinyGPS does not handle retrieving serial data from a GPS unit.) When encode() returns “true”, a valid sentence has just changed the TinyGPS object’s internal state.

gps.stats(&chars, &sentences, &failed_checksum);
This stats method provides a clue whether you are getting good data or not. It provides statistics that help with troubleshooting.

chars – the number of characters fed to the object
sentences – the number of valid $GPGGA and $GPRMC sentences processed
failed_checksum – the number of sentences that failed the checksum test

this is what they say about it but i still dont understand it

4

It is a kludge. The TinyGPS example program tries to do two things at once: print too much data at the wrong time, and keep the GPS input buffer from overflowing. Related thread here, with additional links.

Cheers,
/dev

5

What feedgps( ) does, is it gets the serial chars arriving from the GPS device, it gets each of those chars, one at a time, and feeds them into the gps parser object, using the encode( ) function of the gps object.

When the gps parser object gets a complete and valid "NMEA sentence", this function returns true, otherwise false.

When you get a true returned from this function, that means you have new information from the gps which you can use for whatever.

6

Perhaps instead of reading about the GPS, your comprehension of serial communications might be weak.

I suggest you review the tutorial on serial communications, if you can't understand what the code in feedgps( ) does.