online_utils/nmea0183_checksum_calculator.html

<head>
<title>NMEA0183 Checksum calculator</title>
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<script type="text/javascript">

function NMEA0183_getChecksum(sentence) {
  var result = 0;
  for( var idx = 0; idx < sentence.length; idx++) {
      result = result ^ sentence.charCodeAt(idx);
  }
  return result;
}

function nmeaSnt_onKey() {
  el = document.getElementById("snt_input");
  el.style.width = ((el.value.length + 3) * 8);
  chk_sum = NMEA0183_getChecksum(el.value);
  document.getElementById("chk_sum").innerText = Number(chk_sum).toString(16).padStart(2, "0").toUpperCase();
}

</script>

</head>

<body>
<h1>NMEA0183 Checksum calculator</h1>
<hr>
<p>
<tt>
<big>
<b>$</b><input id="snt_input" type="text" maxlength="128" oninput="nmeaSnt_onKey()" value="GNGLL,4443.1365,N,03749.8815,E,071803.000,A,A"><b>*<a id="chk_sum"></a></b>
</big>
</tt>
</p>
<br>
<i>
<b>Brief description:</b> NMEA0183 checksum is just a simple byte-by-byte XOR of
all the bytes between <b>$</b> and <b>*</b> signs exclusively.
</i>

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<hr>
(C) Alek Dikarev, 2020<br>
For bug reports, suggestions and questions, please feel free to <a href="https://github.com/AlekUnderwater">reach me</a><br>

<script type="text/javascript">

nmeaSnt_onKey();

</script>

</body>
</html>