在矩阵式键盘中，每条水平线和垂直线在交叉处不直接连通，而是通过一个按键加以连接。这样，一个端口（如P1口）就可以构成4*4=16个按键，比之直接将端口线用于键盘多出了一倍，而且线数越多，区别越明显，比如再多加一条线就可以构成20键的键盘，而直接用端口线则只能多出一键（9键）。-n the matrix in the keyboard, each horizontal and vertical line crossing not directly connected, but rather through a button to connection. So, a port (such as P1 mouth) can form 4* 4 = 16 key, is directly used for the keyboard port line a times, and the more line, the more obvious difference, for example, add a line can constitute a 20 key keyboard, and use directly port is the only line a key (9 key).