实现一行显示3个字，共二行6字的点阵电子广告牌.主要实现以下功能：

1.显示一行时，左右滚动显示字符。

2.显示二行时向上滚动显示字符。

-Achieve row shows the three characters, two lines of six-word dot-matrix electronic billboards. Achieve the following key features:

1 show a line scrolling display characters.

2 shows two rows scroll up to display character.