这是一种新型的N+1个端口就可以实现的N*N个矩阵式键盘，与传统的按键相比，这种键盘的优点在于节省了宝贵的I/O口资源，强烈建议大家研究学习！-This is a new type of N+1 ports can be achieved in a matrix N* N-type keyboard, as compared with the traditional keypad, this keyboard has the advantage of saving valuable I/O po