on FIRST chip in chain
      },
   }
</pre>
<p>
   Now you can set up the <a href="JSONConfigRef.htm#buttons.source.type=74hc165"><tt>buttons.source</tt></a>
   for a button wired to a 74HC165 port:
</p>
<pre>
   {
      buttons: [
         // button #0
         {
            source: { type: "74hc165", chip: 0, port: "B" },
         },
      ],
   }
</pre>

<h4>Button action</h4>
<p>
   Okay, you've got the button wired up, and you've defined a <tt>buttons</tt>
   array entry giving its <tt>source</tt>.  Th