逐行扫描法.c

基于c51的484按键扫描源程序 适合初学者

#include <reg51.h>

unsigned int A[16]={0x77,0x7b,0x7d,0x7e,0xb7,0xbb,0xbd,0xbe,0xd7,0xdb,0xdd,0xde,0xe7,0xeb,0xed,0xee};

void main(void)
{
	unsigned int B[4]={0x7f,0xbf,0xdf,0xef};
	unsigned int i,j,i1;
	while(1)
	{
		for(i=0;i<4;i++)
		{
			P0=B[i];
	    	if((P0&0x0f)!=0x0f)
			{
				for(j=0;P0!=A[j];j++);
				for(i1=0;i1<1000;i1++);	
				while((P0&0x0f)!=0x0f);
				while((P0&0x0f)!=0x0f);
				P1=j;
			} 
		}
	}
}