title: undefined symbol in data segment of assembly program
body: <p>Putting the statement <code>data byte 1h</code> in the assembly program builds fine. But when I replace<br>
  the same with <code>data byte AAh</code> it throws an error <br></p>
  <p><code>undefined symbol : AAh</code><br>
  What could be the reason for that AA is a valid hexadecimal character and AA is one byte long<br>
  So why it marks as undefined<br></p>