Revision 0:a6e68073c162, committed 2018-07-23

Comitter:

JackB

Date:

Mon Jul 23 12:23:55 2018 +0000

Commit message:

NMEA

Changed in this revision

diff -r 000000000000 -r a6e68073c162 NMEA0183.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/NMEA0183.cpp	Mon Jul 23 12:23:55 2018 +0000
@@ -0,0 +1,45 @@
+#include "NMEA0183.h"
+
+NMEA0183::NMEA0183()
+{
+}
+
+// CheckParity
+// Returns 1 if valid
+int NMEA0183::CheckParity(char *nmea0183_string)
+{
+    // Calculate parity
+    char parity_calculated = 0x00;
+    for (int i = 1; i < strlen(nmea0183_string)-3; i++) {
+        parity_calculated ^= nmea0183_string[i];
+    }
+
+    // Print parity_calculated to string
+//    char parity_calculated_str[3];
+//    snprintf(parity_calculated_str, 3, "%02x", parity_calculated);
+
+    uint8_t len = strlen(nmea0183_string);
+    char parity_given = hex2dec(nmea0183_string[len-2]) * 16 +  hex2dec(nmea0183_string[len-1]);
+
+    // Compare values
+    if (parity_calculated == parity_given) {
+        return 1;
+    }     
+    return 0;
+}
+
+void NMEA0183::SubString(char *s, char *d, int pos, int len) //usage: substring(Src, Dst, Pos, Len);
+{
+//usage: substring(Source, Destination, pos, len);
+    char *t;
+ 
+    s=s+pos;
+    t=s+len;
+    while (s!=t) {
+        *d=*s;
+        s++;
+        d++;
+    }
+    *d='\0';
+}
+

diff -r 000000000000 -r a6e68073c162 NMEA0183.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/NMEA0183.h	Mon Jul 23 12:23:55 2018 +0000
@@ -0,0 +1,27 @@
+#ifndef __NMEA0183_H__
+#define __NMEA0183_H__
+
+#include "mbed.h"
+ 
+#define NMEA0183_BUF_SIZE 240
+
+class NMEA0183 {
+public:
+    NMEA0183();
+    int CheckParity(char *nmea0183_string);
+
+private:
+    void SubString(char *s, char *d, int pos, int len); //usage: SubString(Src, Dst, Pos, Len);
+
+protected:
+    char buf_[NMEA0183_BUF_SIZE];
+    inline int hex2dec(char c) {
+        if (c >= '0' && c <='9') return c - '0';
+        if (c >= 'a' && c <= 'f') return c - 'a' + 10;
+        if (c >= 'A' && c <= 'F') return c - 'A' + 10;
+        return 0;
+    };
+
+};
+
+#endif