Terry Koziniec / Mbed OS SatChat-GPS-test

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Dependencies:   USBDevice max32630fthr

Files at this revision

API Documentation at this revision

Revision 6:af25f19eb4e6, committed 2017-07-01

Comitter:
koziniec
Date:
Sat Jul 01 02:02:38 2017 +0000
Parent:
5:703f61be6ee2
Child:
7:4218bb385ca4
Commit message:
First attempt at calculating CS. Probably incorrect and doesn't print the CS to screen

Changed in this revision

main.cpp Show annotated file Show diff for this revision Revisions of this file 
--- a/main.cpp	Sat Jul 01 01:35:47 2017 +0000
+++ b/main.cpp	Sat Jul 01 02:02:38 2017 +0000
@@ -29,7 +29,7 @@
     char nmea_descriptor[5] = {0};
     gps_power(on);
     while (1) {
-        char nmea_sentence[82] = {0}; //Fill with NUL terminators
+        char nmea_sentence[82] = {0}; //Fill with NULL terminators
         gps.format(8,Serial::None,1);
         while (gps.getc()!='$');   //wait for start of sentence
         int nmea_index = 0;
@@ -47,6 +47,14 @@
                 nmea_index=80;          //Don't overflow buffer
             }
         }
+        // Checksum
+        bool checksum_valid = FALSE;
+        int checksum = 0;
+        int i = 1;  //After the '$'
+        while (nmea_sentence[i++] != '*'){
+            checksum ^= nmea_sentence[i];
+        }
+        pc.printf( "Checksum: %i\n\r", checksum );
         //     const char s[2] = ",";
         const char gprmc[7] = "$GPRMC";
         char *token;
@@ -77,7 +85,7 @@
     data[1] = 0x19;     //3.3V
     i2c.write( 0x50, data, 2 );
     gps_power(off);
-    wait(5);
+    wait(2);
     while (1) {
         gps_update();
     }