def clear(self, fill = 0x00):
        """!
        \~english
        Clear buffer data and fill color into buffer
        @param fill: a color value, it will fill into buffer.<br>
                The SSD1306 only chosen two colors: <br>
                   0 (0x0): black <br>
                   1 (0x1): white <br>

        \~chinese
        清除缓冲区数据并在缓冲区中填充颜色
        @param fill: 一个颜色值，它会填充到缓冲区中 <br>
                     SSD1306只能选择两种颜色： <br>
                        0（0x0）：黑色 <br>
                        1（0x1）：白色 <br>
        """
        self._buffer = [ fill ] * ( self.width * self._mem_pages )