a name="l00010"></a><span class="lineno">   10</span>&#160;<span class="comment"> */</span></div><div class="line"><a name="l00011"></a><span class="lineno">   11</span>&#160;</div><div class="line"><a name="l00012"></a><span class="lineno">   12</span>&#160; <span class="comment">/** A simple stack, used internally for keeping track of analog input channels as they are read.</span></div><div class="line"><a name="l00013"></a><span class="lineno">   13</span>&#160;<span class="comment"> This stack is really