hex2int: fix hex digit parsing

minmea.c

@@ -19,9 +19,9 @@ static int hex2int(char c)
     if (c >= '0' && c <= '9')
         return c - '0';
     if (c >= 'A' && c <= 'F')
-        return c - 'A';
+        return c - 'A' + 10;
     if (c >= 'a' && c <= 'f')
-        return c - 'a';
+        return c - 'a' + 10;
     return -1;
 }
 

tests.c

@@ -20,6 +20,8 @@ static const char *valid_sequences[] = {
     "$GPGGA,,,,,,0,00,99.99,,,,,,*48",
     "$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*30",
     "$GPGLL,,,,,,V,N*64",
+    "$GPXTE,A,A,0.67,L,N*6F",
+    "$GPXTE,A,A,0.67,L,N*6f",
     NULL,
 };
 
@@ -32,6 +34,8 @@ static const char *invalid_sequences[] = {
     "$$GPGGA,,,,,,0,00,99.99,,,,,,*48",
     "GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*30",
     "gps: $GPGLL,,,,,,V,N",
+    "$GPXTE,A,A,0.67,L,N*6e",
+    "$GPXTE,A,A,0.67,L,N*6g",
     NULL,
 };