以51系列单片机为核心，以开发板为平台，设计一个音乐提示定时器，具备倒数计时、时间修改、音乐演奏等功能。该定时器设置4个按键：K1—设置倒数时间为60分钟，显示为“60”；K2—设置倒数计时时间为5分钟，显示为“05”；K3—设置倒数计时时间为10分钟，显示为“10”；K4—设置倒数计时时间为20分钟，显示为“20”。一旦按键后则开始倒计时，当计时为0则演奏一曲音乐；内定倒数计时时间为5分钟，显示为05。定时器可作为微电脑倒数计数器，做一小段时间计时，放在家中使用，例如煮泡面、煮开水或小睡片刻等；用于全自动洗衣机洗涤完毕音乐提示定时器。设计任务包括控制系统硬件设计和应用程序设计。-51 Series MCU as the core development board as a platform to design a music prompt timer, with countdown, time changes, music and other functions. The timer 4 keys: K1-set the countdown time is 60 minutes, shown as "60"　K2-set countdown timer for 5 minutes, shown as "05"　K3-set countdown time is 10 minutes, showing as "10"　K4-set countdown time is 20 minutes, shown as "20." Once the start button after the countdown, when the time is 0 play a music　default countdown time is 5 minutes, shown as 05. Microcomputer countdown timer can be used as the counter and do a short time duration, on the home use, such as cooking instant noodles, boil water or take a nap, etc.　for automatic washing machine s prompt completion of the timer. Control system design tasks, including hardware design and application design.