本实验使用8253的定时计数器2，GATE2接到开关K1上，CLK2接1MHZ的时钟脉冲，OUT2接示波器观测输出波形，并在数码管上显示“8253---C”。-The timing of the experiments using 8253 counter 2, GATE2 received on the switch K1, CLK2 clock pulses received 1MHZ, OUT2 connected oscilloscope to observe the output wa