设计一个具有8路抢答的抢答器，利用并行接口和开关键来实现，利用逻辑开关K0—K7代表抢答按钮，当某个逻辑开关闭合时，则此时在七段数码管上讲其号码现实出来-Design an 8-way Responder has a Responder, using a parallel interface and open the key to achieve, using the logical switch K0-K7 representatives answer button when a logical switch is closed at this time in terms of its number of seven-segment LED reality come out