code: func (h *JHD1313M1Driver) SetPosition(pos int) (err error) {
  	if pos < 0 || pos > 31 {
  		err = ErrInvalidPosition
  		return
  	}
  	offset := byte(pos)
  	if pos >= 16 {
  		offset -= 16
  		offset |= LCD_2NDLINEOFFSET
  	}
  	err = h.command([]byte{LCD_SETDDRAMADDR | offset})
  	return
  }
docs: // SetPosition sets the cursor and the data display to pos.
  // 0..15 are the positions in the first display line.
  // 16..32 are the positions in the second display line.