title: volatile unsigned int * const
body: <p>In the following line of code, what is the purpose of the <code>const</code> keywords?</p>
  
  <pre><code>volatile unsigned int * const UART0DR = (unsigned int *)0x10009000;
  </code></pre>
  
  <p>I understand the <code>volatile unsigned int *</code> bit, but why is <code>const</code> there?</p>