说明：  此程序测试PCA负边沿触发的捕捉方式，测试前将P0.0同P1.6脚用跳线短接，当P1.6 送出6000个负边沿，在PCA就触发6000次负边沿捕捉
(this negative PCA testing procedures triggered the 2500 catch, test before P0.0 P1.6 feet with a short jumper with Next, when 6,000 P1.6 send negative periphery, PCA in 6000 on the trigger negative edge capture)