Diff: main.cpp

Revision:

13:ff0b39177386

Parent:

12:a895e3581542

Child:

14:8ff04e82bda2

--- a/main.cpp	Sun Jul 02 13:37:27 2017 +0000
+++ b/main.cpp	Mon Jul 03 15:46:51 2017 +0000
@@ -2,9 +2,10 @@
 #include "mbed.h"
 #include "max32630fthr.h"
 #include <stdbool.h>
-#define on 1
-#define off 0
-
+#define ON 0
+#define OFF 1
+#define EXIT_SUCCESS 0
+#define EXIT_FAILURE 1
 Serial pc(USBTX, USBRX);
 Serial gps(P5_3, P5_4, 9600);
 I2C i2c(P5_7,P6_0); // SDA, SCL
@@ -12,7 +13,6 @@
 DigitalOut red_led(LED1,1);
 DigitalOut green_led(LED2,1);
 DigitalOut blue_led(LED3,1);
-
 char gpsfix_last_utc_time[11] = {0};
 char gpsfix_last_utc_date[7] = {0};
 char gpsfix_longtitude[12] = {0};
@@ -23,23 +23,23 @@
 char gpsfix_mag_var_ew[1] = {0};//Set but not used
 char gpsfix_ns = 0;
 char gpsfix_ew = 0;
-
+bool gps_data_present = false;  //If this is false we can't even use stale GPS data.
 
 void gps_power(bool state)
 {
     char    data[2];
     data[0] = 0x16;     //MAX14690 LDO3cfg register
     data[1] = 0xE0;     //Disable LDO3
-    if (state == on) {
+    if (state == ON) {
         data[1] = 0xE2; //Enable LDO3
     }
     i2c.write( 0x50, data, 2 );
 }
 
-void set_epoch_from_last_gps_time(void)
+int get_epoch_from_last_gps_time(void)
 {
     struct tm t;
-    time_t t_of_day;
+    time_t epoch;
     char two_char_str[3] = {0};
     memcpy(two_char_str, gpsfix_last_utc_date+4, 2);
     t.tm_year = atoi(two_char_str)+100;         //Years since 1900
@@ -51,20 +51,31 @@
     t.tm_hour = atoi(two_char_str);
     memcpy(two_char_str, gpsfix_last_utc_time+2, 2);
     t.tm_min = atoi(two_char_str);
-    memcpy(two_char_str, gpsfix_last_utc_time+4, 2);    
+    memcpy(two_char_str, gpsfix_last_utc_time+4, 2);
     t.tm_sec = atoi(two_char_str);
     t.tm_isdst = 0;        // Is DST on? 1 = yes, 0 = no, -1 = unknown
-    t_of_day = mktime(&t);
-    printf("seconds since the Epoch: %ld\n", (long) t_of_day);
+    epoch = mktime(&t);
+    return epoch;
 }
 
-void gps_update(void)
+int gps_update(void)
 {
-    gps_power(on);
-    bool wait_for_fix = true;
-    while (wait_for_fix) {
+#define GPS_TIMEOUT 120;            //Wait two minutes maximum for GPS.
+    gps_power(ON);
+    time_t gps_on_time = time(NULL);    //Start time for GPS timeout calculation.
+    bool wait_for_fix = true;           //Set this to false once a fix is obtained.
+    blue_led = ON;
+    while (wait_for_fix) {              //Keep monitoring the GPS until we get a fix.
+        if ((time(NULL) - gps_on_time ) > 120) {
+            gps_power(OFF);
+            blue_led = OFF;
+            while (gps.readable()) {
+                char dummy = gps.getc();    //Empty serial buffer because overflows reveal MBED bugs :-(
+            }
+            return EXIT_FAILURE;        //Return an error if the GPS takes too long for a fix.
+        }
         int checksum = 0;
-        char nmea_sentence[82] = {0};   //Fill with NULL terminators to save doing it later
+        char nmea_sentence[83] = {0};   //NMEA length max is 82 + 1 terminator. Fill with NULL terminators to save doing it later.
         while (gps.getc()!='$');        //wait for start of sentence
         int nmea_index = 0;
         nmea_sentence[nmea_index] = '$';    //Manually insert the '$' because we don't want it included in the checksum loop
@@ -75,39 +86,41 @@
                 nmea_sentence[++nmea_index] = ' ';  //Pad consecutive comma with a space to make it possible to use strtok with empty values
             }
             nmea_sentence[++nmea_index] = nmea_char; //build the sentence with the next character
-            if (nmea_index > 80) {
-                nmea_index=80;          //Don't overflow buffer
+            if (nmea_index > 81) {
+                nmea_index=81;          //Don't overflow sentence buffer
             }
             nmea_char = gps.getc();     //get next char from GPS
         }
-        //Last character was the '*' so read the two hex digits of CS from gps
+        //Last character was the '*' so next two are CS
         char hex_checksum[3] = {0};
         hex_checksum[0] = gps.getc();
         hex_checksum[1] = gps.getc();
-        if (checksum == (int)strtol(hex_checksum, NULL, 16) ) {
+        if (checksum == (int)strtol(hex_checksum, NULL, 16) ) {     //Compare calc and read checksums.
+
             //Valid sentence so check if it's a GPRMC
-            //pc.printf("Match\n\r");
             const char gprmc[7] = "$GPRMC";
             char *token;
             token = strtok(nmea_sentence, ",");
             if (strcmp(token,gprmc) == 0) {     //GPRMC ?
-                pc.printf( " %s\n\r", token );  //Get the time
+                //pc.printf( " %s\n\r", token );  //Get the time
                 if (token != NULL) {
                     token = strtok(NULL, ",");
-                    if (*token != 32) {         //If there is a time present, record it.
-                        pc.printf("Time: %s\n\r",token);
+                    if (*token != 32) {         //If there is a time present (anything but a space), record it.
+                        //pc.printf("Time: %s\n\r",token);
+                        blue_led =! blue_led;   //Flash blue LED
                         memcpy(gpsfix_last_utc_time, token, sizeof gpsfix_last_utc_time - 1);
                     }
                 }
                 if (token != NULL) {
                     token = strtok(NULL, ",");
-                    if (*token == 'V') {
+                /*    if (*token == 'V') {
                         pc.printf("VOID");
-                    }
-                }
+                    } */
+                } 
                 if (*token == 'A') {                //Is this an 'A'ctive (valid) fix?
                     pc.printf("Got a fix\n\r");
-                    gps_power(off);                 //Yes - No need for GPS now
+                    gps_power(OFF);                 //Yes - No need for GPS now
+                    blue_led = OFF;
                     wait_for_fix = false;           //Stop looping now we have a fix.
                     while (gps.readable()) {
                         char dummy = gps.getc();    //Empty serial buffer because overflows reveal MBED bugs :-(
@@ -134,7 +147,7 @@
                     }
                     if (token != NULL) {
                         token = strtok(NULL, ",");
-                        //pc.printf("Speed in knots: %s\n\r",token);
+                        pc.printf("Speed in knots: %s\n\r",token);
                     }
                     if (token != NULL) {
                         token = strtok(NULL, ",");
@@ -160,9 +173,10 @@
             char dummy = gps.getc();
         }
     }
+    return EXIT_SUCCESS;
 }
 
-int main()
+main()
 {
     char    data[2];
     data[0] = 0x1A;     //MAX14690 BootCfg register
@@ -172,14 +186,60 @@
     data[0] = 0x17;     //MAX14690 LDO3Vset register
     data[1] = 0x19;     //3.3V
     i2c.write( 0x50, data, 2 );
-    gps_power(off);
+    gps_power(OFF);
     wait(2);
-    while (1) {
-        gps_update();
-        set_epoch_from_last_gps_time();
-        wait(600);
+    pc.printf("\n\n\rOpen EPIRB - Simple mode\n\r");
+    pc.printf("Press and hold both side buttons to signal rescue needed\n\r");
+    pc.printf("Full functionality will start in:");
+    for (int i=9; i > 0; i--) {
+        time_t seconds = time(NULL);    //get current epoch
+        pc.printf("%d",i);
+        while(time(NULL) - seconds < 1) {
+            if (true/*button_combination()==SOS_PRESSED*/) {
+                //do the emergency code
+                if (gps_update()==EXIT_SUCCESS) {
+                    gps_data_present = true;
+                    int gps_epoch = get_epoch_from_last_gps_time();
+                    set_time(gps_epoch);
+                    pc.printf("Got a GPS fix and time.\n\r");
+                    pc.printf("Sending SOS in 10 seconds");
+                    green_led=ON;
+                } else {
+                    pc.printf("\n\rGPS timed out and we have no existing fix.\n\r");
+                    pc.printf("We can send an Iridium packet but coordinates are rough.\n\r");
+                }
+                pc.printf("Sending SOS in 10 seconds");
+                red_led=ON;
+                while(true) {}; //STOP HERE
+            }
+        }
+        pc.printf("\b");            //Backspace
     }
-}
+    // normal functionality lives here
+    pc.printf("\n\rStarting normal operation\n\r");
+/*
+    if (true) {         //Temp simulation
+        while (1) {
+            if (gps_update()==EXIT_SUCCESS) {
+                gps_data_present = true;
+                int gps_epoch = get_epoch_from_last_gps_time();
+                set_time(gps_epoch);
+                pc.printf("Got a GPS fix and time.\n\r");
+            } else {
+                pc.printf("GPS timed out and we have no existing fix.\n\r");
+                pc.printf("We can send an Iridium packet but coordinates are rough.\n\r");
+            }
+            time_t seconds = time(NULL);
+            //printf("Time as a basic string = %s", ctime(&seconds));
+            wait(60);
+            seconds = time(NULL);
+
+            wait(33);
+            seconds = time(NULL);
+            printf("Time as a basic string = %s", ctime(&seconds));
+            wait(60);
+        } */
+    }