51单片机代码，此代码驱动时钟芯片DS1302，并且驱动温度传感器DS18B20，产生PWM驱动制冷片，显示在1602液晶屏上。-51 single-chip code, this code-driven clock chip of DS1302, and drive the temperature sensor DS18B20, resulting in a PWM-driven refrigeration piece, shown in 1602 on the LCD screen.