File content as of revision 3:43cb067ecd00:

#include "mbed.h"

#ifdef GPS_

#include "mbed.h"
#include "gps_mod.h"
using namespace std;
#if defined  (TARGET_NUCLEO_L476RG)  //  Computer is low power ARM Cortex development system
#include "BufferedSerial.h"
    BufferedSerial gps_module   (A0, A1);
#endif
#if defined  (TARGET_DISCO_F746NG)  //  Computer is high-end ARM Cortex development system with touch lcd
#include "BufferedSoftSerial.h"
    BufferedSoftSerial gps_module   (A4, A5);
#endif
#ifdef  TARGET_NUCLEO_L432KC
#include "BufferedSerial.h"
    extern  BufferedSerial gps_module;
#endif
gps_mod::gps_mod()  //  Constructor
{
//BufferedSoftSerial gps_module   (_pinTx : A0, _pinRx : A1);
    state = WAITING4DOLLAR;
    destptr = dest;
    strcpy  (latstr, "Invalid\0");
    strcpy  (longstr, "Invalid\0");
    strcpy  (altistr, "Invalid\0");
    strcpy  (timestr, "??:??:??\0");
    chcnt = 0;
    inmsg = false;
    newdata = false;
    posfix[0] = 'x';
    posfix[1] = 0;
    return;
}

bool    gps_mod::new_data()  {
    bool    r;
    r = newdata;
    newdata = false;
    return  r;    
}

bool    gps_mod::fix_valid()
{
    if  (posfix[0] < '1' || posfix[0] > '3')    return  false;
    return  true;
}

char * gps_mod::date ()  {
    return  datestr;
}

char * gps_mod::heading ()   {
    return  headingstr;
}

char * gps_mod::mph ()   {
    return  speed_mphourstr;
}

char *     gps_mod::position_fix_indicator  ()
{
    return  posfix;
}

char * gps_mod::latitude()
{
    if  (fix_valid())    return  latstr;
    return  "No Fix ";
}

char * gps_mod::longitude()
{
    if  (fix_valid())    return  longstr;
    return  "No Fix ";
}

char * gps_mod::altitude()
{
    if  (fix_valid())    return  altistr;
    return  "No Fix ";
}

char * gps_mod::sat_count ()
{
    return  numofsats;
}

char * gps_mod::message(int mess_num)
{
    if  (mess_num < 0 || mess_num > 5)
        return  NULL;
    return  dest + mess_num * (MAXMSGLEN + 4);
}

char * gps_mod::time ()
{
//    char * t = message(0);
    return  timestr;
}

double gps_mod::lat_merged ()
{
    double  result = strtod (latstr, NULL);
    return  result + (strtod (latstr + 3, NULL) / 60.0);
}

double gps_mod::lon_merged ()
{
    double  result = strtod (longstr, NULL);
    return  result + (strtod (longstr + 4, NULL) / 60.0);
}

int gps_mod::update()
{
    static const char month_tab[] = "---\0Jan\0Feb\0Mar\0Apr\0May\0Jun\0Jul\0Aug\0Sep\0Oct\0Nov\0Dec\0";
    const int MAX_COMMAS_IN_MSG = 24;
    int date, month;
    while   (gps_module.readable())  {
        ch = gps_module.getc();
        switch  (state) {
            case    WAITING4DOLLAR:
                i = 0;
                if  (ch == '$') state = GOTDOLLAR;
                break;
            case    GOTDOLLAR:  //  accumulate 5 chars after '$'
                hdracc[i++] = ch;
                hdracc[i] = 0;
                if  (i > 4) {
                    i = -1;
                    state = GOTHDR;
                }
                break;
            case    GOTHDR: //  have read "$GP???" to get here
//                if  (ch != ',') pc.printf   ("Oops, comma missing\r\n");
                if      (strncmp(hdracc,"GPGGA",5) == 0)  i = 0;
                else if (strncmp(hdracc,"GPGLL",5) == 0)  i = 1;
                else if (strncmp(hdracc,"GPGSA",5) == 0)  i = 2;
                else if (strncmp(hdracc,"GPGSV",5) == 0)  i = 3;
                else if (strncmp(hdracc,"GPRMC",5) == 0)  i = 4;//161229.487,A,3723.24756, N,12158.34162,W,     0.13,       309.62,  120598,,*10
                //                                                  time     ?    lat            lon      ground speed knots|heading|date
                else if (strncmp(hdracc,"GPVTG",5) == 0)  i = 5;
                if  (i < 0) state = WAITING4DOLLAR;     //  Found invalid header info
                else    {                               //  Validated header info
                    destptr = message(i);
                    chcnt = 0;
                    state = WAITING4CR;
                }
                break;
            case    WAITING4CR:
                if  (ch == '\r')  {
                    state = WAITING4LF;     //  process new string data here
                    int comma_count = 0, comma_positions[MAX_COMMAS_IN_MSG + 2];
                    for (int j = 0; j < strlen(destptr) && j < MAXMSGLEN && comma_count < MAX_COMMAS_IN_MSG; j++)  {
                        if  (destptr[j] == ',') {
                            comma_positions[comma_count++] = j;
                            comma_positions[comma_count] = 0;
                        }
                    }
                    switch  (i) {
                        case    0:  //  GGA 183655.00,5110.25620,N,00320.09926,W,1,11,0.80,59.9,M,49.5,M,,*74
                            if  (comma_positions[0] == 9)    {   //  time data seems to exist
                                timestr[0] = dest[0];
                                timestr[1] = dest[1];
                                timestr[2] = ':';
                                timestr[3] = dest[2];
                                timestr[4] = dest[3];
                                timestr[5] = ':';
                                timestr[6] = dest[4];
                                timestr[7] = dest[5];
                                timestr[8] = 0;
                            } else    {
                                strcpy  (timestr, "Invalid");
                            }
                            posfix[0] = dest[comma_positions[4] + 1];
                            if  (fix_valid())   {
                                int a = 0, b = comma_positions[5] + 1;   //  get numof sats
                                if  (dest[b] == ',')    {
                                    numofsats[0] = '-';
                                    numofsats[1] = '-';
                                }
                                else    {
                                    numofsats[0] = dest[b++];
                                    numofsats[1] = dest[b++];
                                }
                                b = comma_positions[7] + 1;  //  get altitude
                                char c;
                                while   ((c = dest[b++]) != ',' && a < 7)
                                    altistr[a++] = c;
                                altistr[a] = 0;
                            }
                            numofsats[2] = 0;
                            break;
                        case    1:  //  GLL 5110.25606,N,00320.10001,W,183752.00,A,A*72
                            latstr[0] = destptr[0];
                            latstr[1] = destptr[1];
                            latstr[2] = '~';
                            latstr[3] = destptr[2];
                            latstr[4] = destptr[3];
                            latstr[5] = '.';
                            for (int k = 5; k < 10; k++)
                                latstr[k + 1] = destptr[k];
                            latstr[11] = ' ';
                            latstr[12] = destptr[11];   //  N or S
                            latstr[13] = 0;
                            for (int k = 0; k < 3; k++)
                                longstr[k] = destptr[k + 13];
                            longstr[3] = '~';
                            longstr[4] = destptr[16];
                            longstr[5] = destptr[17];
                            longstr[6] = '.';
                            for (int k = 7; k < 12; k++)
                                longstr[k] = destptr[k + 12];
                            longstr[12] = ' ';
                            longstr[13] = destptr[25];  //  E or W
                            longstr[14] = 0;
                            break;
                        case    2:  //  GSA A,3,11,22,01,03,17,23,19,14,09,,,,1.72,0.97,1.42*0E
                            break;
                        case    3:  //  GSV complex multiple
                            break;  //               0             1              2 3      4            5        67
                        case    4:  //  RMC 184111.00, A,5110.25663, N,00320.10076,W, 0.223,            ,  090816,,,A*6B
//                                  //      161229.487,A,3723.24756, N,12158.34162,W, 0.13,       309.62,  120598,,*10
//                                           time     ?    lat            lon  ground speed knots|heading|date
                            if  (comma_positions[6] + 1 == comma_positions[7])  //  no heading data exists
                                strcpy  (headingstr, "-/-");
                            else
                                sprintf(headingstr, "%.1f", strtod(destptr + comma_positions[6] + 1, NULL));
//                            pc.printf("%s ^%s^", destptr, headingstr);
                            date =  (destptr[comma_positions[7] + 1] - '0') * 10 + (destptr[comma_positions[7] + 2] - '0');
                            month = (destptr[comma_positions[7] + 3] - '0') * 10 + (destptr[comma_positions[7] + 4] - '0');
                            if  (month > 12 || month < 1)
                                month = 0;
                            month *= 4;
                            sprintf (datestr, "%d %s 20%d", date, &month_tab[month], strtol(&destptr[comma_positions[7] + 5], NULL, 10));
                            break;
                        case    5:  //  VTG       ,T   ,             ,M,0.098,N,0.181,K,A*2A course over ground and ground speed
//$                                   GPVTG 309.62,T   ,             ,M,0.13, N,0.2,  K*6E
                            sprintf (speed_mphourstr, "%.1fmph", km2miles * strtod(destptr + comma_positions[5] + 1, NULL));
                            newdata = true;
                            break;  //      course true|course magnetic|knots|km/hour
                        default:
//                            pc.printf   ("Naf i = %d\r\n", i);
                            break;
                    }
                } else    { //  char is not CR
                    if  (chcnt > MAXMSGLEN)    chcnt = MAXMSGLEN;
                    destptr[chcnt++] = ch;
                    destptr[chcnt] = 0;
                }
                break;
            case    WAITING4LF:
//                if  (ch != '\n')
//                    pc.printf   ("Oops, no LF\r\n");
                state = WAITING4DOLLAR;
                break;
            default:
                break;
        }
    }
    return 0;
}   //      end of int gps_mod::update()

#endif