Adafruit_GPS.cpp

/***********************************
This is a our GPS library

Adafruit invests time and resources providing this open source code, 
please support Adafruit and open-source hardware by purchasing 
products from Adafruit!

Written by Limor Fried/Ladyada  for Adafruit Industries.  
BSD license, check license.txt for more information
All text above must be included in any redistribution
 
Mods by J.Isdale (MauiJerry) to support HardwareSerial
****************************************/

#include <Adafruit_GPS.h>

// how long are max NMEA lines to parse?
#define MAXLINELENGTH 120

// we double buffer: read one line in and leave one for the main program
volatile char line1[MAXLINELENGTH];
volatile char line2[MAXLINELENGTH];
// our index into filling the current line
volatile uint8_t lineidx=0;
// pointers to the double buffers
volatile char *currentline;
volatile char *lastline;
volatile boolean recvdflag;


// might be migrating this to parseNEMA
boolean Adafruit_GPS::parse(char *nmea) {
  // do checksum check

  // first look if we even have one
  if (nmea[strlen(nmea)-4] == '*') {
    uint16_t sum = parseHex(nmea[strlen(nmea)-3]) * 16;
    sum += parseHex(nmea[strlen(nmea)-2]);
    
    // check checksum 
    for (uint8_t i=1; i < (strlen(nmea)-4); i++) {
      sum ^= nmea[i];
    }
    if (sum != 0) {
      // bad checksum :(
      //return false;
    }
  }

  // look for a few common sentences
  if (strstr(nmea, "$GPGGA")) {
    // found GGA
    char *p = nmea;
    // get time
    p = strchr(p, ',')+1;
    float timef = atof(p);
    uint32_t time = timef;
    hour = time / 10000;
    minute = (time % 10000) / 100;
    seconds = (time % 100);

    milliseconds = fmod(timef, 1.0) * 1000;

    // parse out latitude
    p = strchr(p, ',')+1;
    latitude = atof(p);

    p = strchr(p, ',')+1;
    if (p[0] == 'N') lat = 'N';
    else if (p[0] == 'S') lat = 'S';
    else if (p[0] == ',') lat = 0;
    else return false;

    // parse out longitude
    p = strchr(p, ',')+1;
    longitude = atof(p);

    p = strchr(p, ',')+1;
    if (p[0] == 'W') lon = 'W';
    else if (p[0] == 'E') lon = 'E';
    else if (p[0] == ',') lon = 0;
    else return false;

    p = strchr(p, ',')+1;
    fixquality = atoi(p);

    p = strchr(p, ',')+1;
    satellites = atoi(p);

    p = strchr(p, ',')+1;
    HDOP = atof(p);

    p = strchr(p, ',')+1;
    altitude = atof(p);
    p = strchr(p, ',')+1;
    p = strchr(p, ',')+1;
    geoidheight = atof(p);
    return true;
  }
  if (strstr(nmea, "$GPRMC")) {
   // found RMC
    char *p = nmea;

    // get time
    p = strchr(p, ',')+1;
    float timef = atof(p);
    uint32_t time = timef;
    hour = time / 10000;
    minute = (time % 10000) / 100;
    seconds = (time % 100);

    milliseconds = fmod(timef, 1.0) * 1000;

    p = strchr(p, ',')+1;
    // Serial.println(p);
    if (p[0] == 'A') 
      fix = true;
    else if (p[0] == 'V')
      fix = false;
    else
      return false;

    // parse out latitude
    p = strchr(p, ',')+1;
    latitude = atof(p);

    p = strchr(p, ',')+1;
    if (p[0] == 'N') lat = 'N';
    else if (p[0] == 'S') lat = 'S';
    else if (p[0] == ',') lat = 0;
    else return false;

    // parse out longitude
    p = strchr(p, ',')+1;
    longitude = atof(p);

    p = strchr(p, ',')+1;
    if (p[0] == 'W') lon = 'W';
    else if (p[0] == 'E') lon = 'E';
    else if (p[0] == ',') lon = 0;
    else return false;

    // speed
    p = strchr(p, ',')+1;
    speed = atof(p);

    // angle
    p = strchr(p, ',')+1;
    angle = atof(p);

    p = strchr(p, ',')+1;
    uint32_t fulldate = atof(p);
    day = fulldate / 10000;
    month = (fulldate % 10000) / 100;
    year = (fulldate % 100);

    // we dont parse the remaining, yet!
    return true;
  }

  return false;
}

char Adafruit_GPS::read(void) {
  char c = 0;
  
  if (paused)
    return c;

   if (gpsSwSerial){
		if (gpsSwSerial->available()) {
			c = gpsSwSerial->read();
		}
   } else if (gpsHwSerial){
		if (gpsHwSerial->available()) {
			c = gpsHwSerial->read();
		}
   }
   if (!c) return c;

    //Serial.print(c);

    if (c == '$') {
      currentline[lineidx] = 0;
      lineidx = 0;
    }
    if (c == '\n') {
      currentline[lineidx] = 0;

      if (currentline == line1) {
        currentline = line2;
        lastline = line1;
      } else {
        currentline = line1;
        lastline = line2;
      }
      

      //Serial.println("----");
      //Serial.println((char *)lastline);
      //Serial.println("----");
      lineidx = 0;
      recvdflag = true;
    }
    
    currentline[lineidx++] = c;
    if (lineidx >= MAXLINELENGTH)
      lineidx = MAXLINELENGTH-1;

  return c;
}

// Constructor when using SoftwareSerial or NewSoftSerial
#if ARDUINO >= 100
Adafruit_GPS::Adafruit_GPS(SoftwareSerial *ser)
#else
  Adafruit_GPS::Adafruit_GPS(NewSoftSerial *ser) 
#endif
{
  common_init();  // Set everything to common state, then...
  gpsSwSerial = ser; // ...override swSerial with value passed.

  recvdflag = false;
  paused = false;
  lineidx = 0;
  currentline = line1;
  lastline = line2;
  
  hour = minute = seconds = year = month = day = milliseconds = 0;
  latitude = longitude = geoidheight = altitude = 0;
  speed = angle = magvariation = HDOP = 0;
  lat = lon = mag = 0;
  fix = false;
  fixquality = satellites = 0;
}


// added by isdale@gmail.com 4.5.12
Adafruit_GPS::Adafruit_GPS(HardwareSerial *ser) 
{
	common_init();  // Set everything to common state, then...
	gpsHwSerial = ser; // ...override hwSerial with value passed.	
}

// Initialization code used by all constructor types
void Adafruit_GPS::common_init(void) {
  gpsSwSerial  = NULL;
  gpsHwSerial  = NULL;
	
	// set other values for defaults
	recvdflag = false;
	paused = false;
	lineidx = 0;
	currentline = line1;
	lastline = line2;
	
	hour = minute = seconds = year = month = day = milliseconds = 0;
	latitude = longitude = geoidheight = altitude = 0;
	speed = angle = magvariation = HDOP = 0;
	lat = lon = mag = 0;
	fix = false;
	fixquality = satellites = 0;
}

void Adafruit_GPS::begin(uint16_t baud) 
{
	if (gpsSwSerial)
		gpsSwSerial->begin(baud);
	else if (gpsHwSerial)
		gpsHwSerial->begin(baud);
}

void Adafruit_GPS::sendCommand(char *str) {
	if (gpsSwSerial)
		gpsSwSerial->println(str);
	else if (gpsHwSerial)
		gpsHwSerial->println(str);
}



boolean Adafruit_GPS::newNMEAreceived(void) {
  return recvdflag;
}


void Adafruit_GPS::pause(boolean p) {
  paused = p;
}

char *Adafruit_GPS::lastNMEA(void) {
  recvdflag = false;
  return (char *)lastline;
}


// read a Hex value and return the decimal equivalent
uint8_t Adafruit_GPS::parseHex(char c) {
    if (c < '0')
      return 0;
    if (c <= '9')
      return c - '0';
    if (c < 'A')
       return 0;
    if (c <= 'F')
       return (c - 'A')+10;
}


boolean Adafruit_GPS::waitForSentence(char *wait4me, uint8_t max) {
  char str[20];

  uint8_t i=0;
  while (i < max) {
    if (newNMEAreceived()) { 
      char *nmea = lastNMEA();
      strncpy(str, nmea, 20);
      str[19] = 0;
      i++;

      if (strstr(str, wait4me))
	return true;
    }
  }

  return false;
}

boolean Adafruit_GPS::LOCUS_StartLogger(void) {
  sendCommand(PMTK_LOCUS_STARTLOG);
  recvdflag = false;
  return waitForSentence(PMTK_LOCUS_LOGSTARTED);
}


boolean Adafruit_GPS::LOCUS_ReadStatus(void) {
  sendCommand(PMTK_LOCUS_QUERY_STATUS);
  
  if (! waitForSentence("$PMTKLOG"))
    return false;

  char *response = lastNMEA();
  uint16_t parsed[10];
  uint8_t i;
  
  for (i=0; i<10; i++) parsed[i] = -1;
  
  response = strchr(response, ',');
  for (i=0; i<10; i++) {
    if (!response || (response[0] == 0) || (response[0] == '*')) 
      break;
    response++;
    parsed[i]=0;
    while ((response[0] != ',') && 
	   (response[0] != '*') && (response[0] != 0)) {
      parsed[i] *= 10;
      char c = response[0];
      if (isDigit(c))
        parsed[i] += c - '0';
      else
        parsed[i] = c;
      response++;
    }
  }
  LOCUS_serial = parsed[0];
  LOCUS_type = parsed[1];
  if (isAlpha(parsed[2])) {
    parsed[2] = parsed[2] - 'a' + 10; 
  }
  LOCUS_mode = parsed[2];
  LOCUS_config = parsed[3];
  LOCUS_interval = parsed[4];
  LOCUS_distance = parsed[5];
  LOCUS_speed = parsed[6];
  LOCUS_status = !parsed[7];
  LOCUS_records = parsed[8];
  LOCUS_percent = parsed[9];

  return true;
}