title: Android responds to PN532 InListPassiveTarget
body: <p>I have a weird situation where I'm trying to toggle my PN532 between tag emulation and tag reader mode. The reader goes for ~70ms and the tag emulation runs for ~600ms.</p>
  
  <p>What I want to happen is that when I put my Android device near the antenna, that it reads the emulated tag. When I hold an NFC tag to the PN532, it's supposed to read the tag.</p>
  
  <p>The solution I have is somewhat working but I'm seeing a weird situation where when I call <code>readPassiveTargetID</code> to test for the presence of passive tags, Android is responding.  This would be fine but I think that Android is spinning up a service which blocks it from reading the emulated tag.</p>
  
  <p>When testing this out, sometimes the devices don't communicate at all with the PN532 but when they do it's most often with the reader mode. Here is the output I get when this happens:</p>
  
  <p>Nexus 5x (Android 6):</p>
  
  <pre><code>&lt;&lt; 4A 1 0
  &gt;&gt; 4B 1 1 0 4 60 4 1 2 3 4 5 78 80 71 0
  </code></pre>
  
  <p>Galaxy S4 (Android 5.0.1):</p>
  
  <pre><code>&lt;&lt; 4A 1 0
  &gt;&gt; 4B 1 1 0 4 20 4 8 87 F6 62 5 78 B3 70 2
  </code></pre>
  
  <p>The 5x will often read the emulated tag after a second or so but the S4 rarely reads the tag when I am toggling between the two modes.  When I just run tag emulation both devices work flawlessly.</p>
  
  <p>I'm thinking that there might be a few problems with what I'm doing.  </p>
  
  <ol>
  <li>Do I need to do something special to toggle between the modes? I don't actually reset or reinitialize the PN532 when I toggle.</li>
  <li>Is there a command I can send to tell the devices to stop listening or a setting I can send that will fix this?</li>
  </ol>