  */
 
 #include <du-ino_function.h>
+#include <du-ino_dsp.h>
 #include <du-ino_widgets.h>
 #include <du-ino_save.h>
 #include <avr/pgmspace.h>

        }
      }

      cv_out(CO1, cv_current_);
      cv_out(CO3, cv_current_ / 2.0);
    }
    else if (gate_)
    {


    // output full display
    Display.display();

    // initialize filter
    env_lpf_ = new DUINO_Filter(DUINO_Filter::LowPass, 100.0, 0.0);

    // attach gate interrupt
    gt_attach_interrupt(GT3, gate_isr, CHANGE);
