CLK0的输入脉冲周期 =1 / 5MHz =0.2μs计数器0的初值 =5ms / 0.2μs =25000d =61A8h.因为 OUT0接CLK1，所以CLK1的输入时钟周期 =5ms计数器1的初值 =5s / 5ms =1000d =3E8h
