1. 设有8bits符号数X存于外部RAM单元，按以下方式计算后的结果Y也存于外部RAM单元，请按要求编写程序。



2. 利用51系列单片机设计一个24小时制电子时钟，电子时钟的时、分、秒数值分别通过P0、P1、P2端口输出（以压缩BCD码的形式）。P3.0为低电平时开始计时，为高电平时停止计时。

-(1) has a number of 8bits symbol X is stored in external RAM unit, calculated as follows the results of Y is also stored in external RAM unit, the programming required. 2 51 series single-chip design of a 24-hour electronic clock, electronic clock, minute, seconds values, respectively, by P0, P1, P2 port output (in the form of compressed BCD code). P3.0 is low, the start time, stop the clock is high.