File content as of revision 1:96d7d157b384:

/***********************************
This is 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
****************************************/

#include "MBed_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 uint16_t lineidx=0;
// pointers to the double buffers
volatile char *currentline;
volatile char *lastline;
volatile bool recvdflag;
volatile bool inStandbyMode;


bool 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((double) 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((double) 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(!gpsSerial->readable()) return c;
    c = gpsSerial->getc();

    //Serial.print(c);

//  if (c == '$') {     //please don't eat the dollar sign - rdl 9/15/14
//    currentline[lineidx] = 0;
//    lineidx = 0;
//  }
    if (c == '\n') {
        currentline[lineidx] = 0;

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

        lineidx = 0;
        recvdflag = true;
    }

    currentline[lineidx++] = c;
    if (lineidx >= MAXLINELENGTH)
        lineidx = MAXLINELENGTH-1;

    return c;
}

Adafruit_GPS::Adafruit_GPS (Serial *ser)
{
    common_init();     // Set everything to common state, then...
    gpsSerial = ser; // ...override gpsSwSerial with value passed.
}

// Initialization code used by all constructor types
void Adafruit_GPS::common_init(void)
{
    gpsSerial = NULL;
    recvdflag   = false;
    paused      = false;
    lineidx     = 0;
    currentline = line1;
    lastline    = line2;

    hour = minute = seconds = year = month = day =
                                         fixquality = satellites = 0; // uint8_t
    lat = lon = mag = 0; // char
    fix = false; // bool
    milliseconds = 0; // uint16_t
    latitude = longitude = geoidheight = altitude =
            speed = angle = magvariation = HDOP = 0.0; // float
}

void Adafruit_GPS::begin(int baud)
{
    gpsSerial->baud(baud);
    wait_ms(10);
}

void Adafruit_GPS::sendCommand(char *str)
{
    gpsSerial->printf("%s\r\n",str);
}

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

void Adafruit_GPS::pause(bool 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;
    // if (c > 'F')
    return 0;
}

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

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

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

    return false;
}

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

bool 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;
}

// Standby Mode Switches
bool Adafruit_GPS::standby(void)
{
    if (inStandbyMode) {
        return false;  // Returns false if already in standby mode, so that you do not wake it up by sending commands to GPS
    } else {
        inStandbyMode = true;
        sendCommand(PMTK_STANDBY);
        //return waitForSentence(PMTK_STANDBY_SUCCESS);  // don't seem to be fast enough to catch the message, or something else just is not working
        return true;
    }
}

bool Adafruit_GPS::wakeup(void)
{
    if (inStandbyMode) {
        inStandbyMode = false;
        sendCommand("");  // send byte to wake it up
        return waitForSentence(PMTK_AWAKE);
    } else {
        return false;  // Returns false if not in standby mode, nothing to wakeup
    }
}