code: public void dim(boolean dim) {
          byte contrast;
  
          if (dim) {
              contrast = 0; // Dimmed display
          } else {
              if (vccState == VCC.EXTERNAL) {
                  contrast = (byte) 0x9F;
              } else {
                  contrast = (byte) 0xCF;
              }
          }
          // the range of contrast to too small to be really useful
          // it is useful to dim the display
          command(setContrast(contrast));
      }
docs: Dims the display
  
  @param dim true - display is dimmed, false - display is normal