说明：  本程序提供AVR单片机ATMEL8515的光控倒数计时后自动报警程序。属于AVR单片机的综合应用。程序简单易懂，注释可读性强。
(This program provides the light control AVR microcontroller ATMEL8515 countdown to automatically alarm program. AVR microcontroller are integrated application. Procedures are simple and easy to understand, notes readable.)