File content as of revision 7:4218bb385ca4:

#include "mbed.h"
#include "max32630fthr.h"
#include <stdbool.h>
#define on 1
#define off 0

Serial pc(USBTX, USBRX);
Serial gps(P5_3, P5_4, 9600);
I2C i2c(P5_7,P6_0); // SDA, SCL

DigitalOut red_led(LED1,1);
DigitalOut green_led(LED2,1);
DigitalOut blue_led(LED3,1);

void gps_power(bool state)
{
    char    data[2];
    data[0] = 0x16;     //MAX14690 LDO3cfg register
    data[1] = 0xE0;     //Disable LDO3
    if (state == on) {
        data[1] = 0xE2; //Enable LDO3
    }
    i2c.write( 0x50, data, 2 ); 
}

void gps_update(void)
{
    gps_power(on);
    while (1) {
        int checksum = 0;
        char nmea_sentence[82] = {0}; //Fill with NULL terminators
        //gps.format(8,Serial::None,1);
        while (gps.getc()!='$');    //wait for start of sentence
        int nmea_index = 0;
        nmea_sentence[nmea_index] = '$';    //Manually insert the '$' because we don't want it included in the checksum loop
        char nmea_char = gps.getc();             //get sentence first char from GPS
        while (nmea_char != '*') {
 //           pc.putc(nmea_char);
            checksum ^= nmea_char;        //Calc checksum as we read sentence
            if ((nmea_sentence[nmea_index] == ',')&&(nmea_char == ',')) {
                nmea_sentence[++nmea_index] = ' ';  //Pad consecutive comma with a space
            }
            nmea_sentence[++nmea_index] = nmea_char; //build the sentence with the next character
            if (nmea_index > 80) {
                nmea_index=80;          //Don't overflow buffer
            }
            nmea_char = gps.getc();     //get next char from GPS
        }
        //read two hex digits of CS from gps
        char msb_gps_checksum = gps.getc();
        char lsb_gps_checksum = gps.getc();



        //     const char s[2] = ",";
        const char gprmc[7] = "$GPRMC";
        char *token;
        token = strtok(nmea_sentence, ",");
        if (strcmp(token,gprmc) == 0) {
            pc.printf( " %s\n\r", token );
            while (token != NULL) {
                token = strtok(NULL, ",");
       //         pc.printf( " %s\n\r", token );
            }
     //               pc.printf("GPS CS:");
        pc.putc(msb_gps_checksum);
        pc.putc(lsb_gps_checksum);
        pc.printf("%d \n\r",checksum);
        }

        while (gps.readable()) {
            char dummy = gps.getc();
        }
    }

}
int main()
{
//
    char    data[2];
    data[0] = 0x1A;     //MAX14690 BootCfg register
    data[1] = 0x30;     //Always-On Mode, off state via PWR_OFF_CMD
    i2c.write( 0x50, data, 2 );

    data[0] = 0x17;     //MAX14690 LDO3Vset register
    data[1] = 0x19;     //3.3V
    i2c.write( 0x50, data, 2 );
    gps_power(off);
    wait(2);
    while (1) {
        gps_update();


    }
}