程序

#include <REGX52.H>void  main() 
{while(1) {if(P3_1 == 0)	//DOWN{P2_0 = 0xFE;}if(P3_1 == 1)	//UP{P2_0 = 0XFF;}};}

按键的抖动问题

软件实现解决-按键的抖动问题

通过延时解决

#include <REGX52.H>void Delay(unsigned int xms)		
{while(xms){unsigned char data i, j;i = 2;j = 239;do{while (--j);} while (--i);xms--;};
}void main() 
{while(1) {if(P3_1 == 0)	//down{Delay(20);	while(P3_1 == 0);	//check downDelay(20);P2_0 = ~P2_0;		//change}};}