这是几个实现键盘操作的程序，可以根据需要直接调用。 //矩阵式键盘单键输入应用，3×4 //P2口作为键盘的接口-This is the number of operating procedures for the realization of the keyboard, you can direct calls as needed.// Matrix-style one-touch keyboard input applications, 3 × 4// P2 mouth as a k