原理图如下，row1~row4为列信号，line1~line4为行信号，采集按键信号时，先将行信号全置为0，然后读取列信号，判断列信号是否有0信号，若有0信号，则表示有按键按下，再根据行与列的状态判断是哪个按键按下，并用发光二极管以16进制形式指示。-The following schematic, row1 ~ row4 for the out signal, line1 ~ line4 for line signals, signal acquisition button, the first full-line home signal to 0, and then read out the signal, signal out to determine whether there are 0 signal, if signal 0 , then press the indicated button, and then in accordance with the state of rows and columns to determine which button is depressed, and 16-band light-emitting diodes to form instructions.