alog_reference is not part TEENSY 2.0 codebase</span></div><div class="line"><a name="l00156"></a><span class="lineno">  156</span>&#160;    ADMUX = (1 &lt;&lt; REFS0) | (channel &amp; 0x07); <span class="comment">// TB2017 this overwrote analog_reference</span></div><div class="line"><a name="l00157"></a><span class="lineno">  157</span>&#160;<span class="preprocessor">#</span><span class="preprocessor">else</span></div><div class="line"><a name="l00158"></a><span class="lineno">  158</span>&#160;    ADMUX