   
   virtual void setup()
   {
-    // TODO: attach GT3 to hardware clock isr that sets clock to EXT
-    gt_attach_interrupt(GT3, clock_isr, CHANGE);
+    gt_attach_interrupt(GT3, clock_ext_isr, CHANGE);
     gt_attach_interrupt(GT4, reset_isr, RISING);
   }
 

      display_changed[2] = true;
    }

    // update display
    if(display_changed[0])
    {


DUINO_Filter * slew_filter;

void clock_ext_isr();
void clock_isr();
void reset_isr();

