实现单片机电子万年历的所有功能，包括键盘控制修改时间，闹钟，定时提醒，时间日期显示-MCU electronic calendar of all the features, including keyboard modification time, alarm clock, time reminder, time and date display

CPLD的烧录程序，保证与单片机数据互通，提供串口引脚约束。-CPLD burning procedures to ensure that the data exchange with the microcontroller, providing serial pin constraints.