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电子秒表的设计 1、用系统8253定时器提供的55ms定时单位，设计秒表定时程序。 2、有关系统定时方法： PC机系统中的8253定时器0工作于方式3，外部提供一个时钟作为CLK信号, 频率：f=1.1931816MHz。 定时器0输出方波的频率:fout=1.1931816/65536=18.2Hz。 输出方波的周期Tout=1/18.2=54.945ms。8253A每隔55ms引起一次中断-Electronic stopwatch design one, using the system timer 8253 provides 55ms timing units, design stopwatch timing procedures. 2, the system timing method: PC system timer 0 of 8253 working in the way of 3, to provide an external clock as the CLK signal, the frequency: f = 1.1931816MHz. Timer 0 output square wave frequency: fout = 1.1931816/65536 = 18.2Hz. Cycle square wave output Tout = 1/18.2 = 54.945ms. 8253A every 55ms caused a disruption
