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名称：外部中断0电平触发

内容：通过中断接口P3.2连接的独立按键测试，按一次P1口的LED灯反向，

这里使用电平触发，所以一直按键不松开和一次按键效果不相同，按下会看到灯全部亮

　　　　说明中断一直在作用-　Name: External Interrupt 0 level trigger

　: Interrupt the interface P3.2 connection, independent of the key test, a P1 port LED lights reverse

　　　　Level trigger, it has been the key to not let go, and a key result is not the same, the press will see the light all the bright

Help interrupt has been the role of