哦!原来还必须用中断来刷新!? 看来是的,呵呵,我是在I0.0的上升沿中断里比较HC4的当前值和预置值的大小的......

Note:
Status bits are valid only while the high-speed counter interrupt routine is being executed. The purpose of monitoring the state of the high-speed counter is to enable interrupts for the events that are of consequence to the operation being performed.
就上面一句话了,看来还得看这头痛的洋文了... 谢谢版主!