cs19-2.c

《手把手教你学单片机的C程序设计》及实验程序

#include<REG51.H>
#define uchar unsigned char
#define uint unsigned int
uchar code DIS_SEG7[16]={0x3f,0x06,0x5b,0x4f,0x66,
                0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
uchar code DIS_BIT[8]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};
uchar code SKEY[16]={10,11,12,13,3,6,9,14,2,5,8,0,1,4,7,15};
uchar code act[4]={0xfe,0xfd,0xfb,0xf7};
//========================
void delay(uint k)
{
uint data i,j;
for(i=0;i<k;i++){
for(j=0;j<121;j++)
{;}}
}
//===========================
char scan_key(void)
{
uchar i,j,in,ini,inj;
bit find=0;
	for(i=0;i<4;i++)
	{
	P1=act[i];
	delay(10);
	in=P1;
	in=in>>4;
	in=in|0xf0;
		for(j=0;j<4;j++)
		{
		  if(act[j]==in)
		  {find=1;
		  inj=j;ini=i;
		  }
		}
	}
	if(find==0)return -1;
	return (ini*4+inj);
}
//============================
void main(void)
{	char c;
	uchar key_value;
	while(1)
	{
		c=scan_key();
		if(c!=-1)key_value=SKEY[c];
		P0=DIS_SEG7[key_value];
		P2=DIS_BIT[0];
		delay(2);
	}
}