设计一个倒计时器，由单片机接收小键盘阵列设定的倒计时时间，倒计时范围最大为60分钟，由数码管显示模块显示剩余时间，显示格式为XX（分）：XX（秒），精确到1S的整数倍。倒计时时间到，由LED亮闪烁灯发出报警。-Design a countdown, received by the microcontroller keypad array to set the countdown time countdown range up to 60 minutes, the digital display module displays the remaining time display format for XX (sub): XX (seconds), accurate to 1San integer multiple of. The countdown time to the alarm LED lights flashing lights.