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代碼里面標(biāo)紅的那塊，有點(diǎn)疑問(wèn)。不知道這段代碼的意思。為什么要賦0xfe給P1，不是要檢測(cè)P1的電位嗎？賦了0xfe給P1，還怎么檢測(cè)？
#include <reg52.h>
#include <intrins.h>
#define uchar unsigned char
#define uint unsigned int
uchar code DSY_CODE[]=
{
0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e,0x00
};
uchar code KeyCodeTable[]=
{
0x11,0x12,0x14,0x18,0x21,0x22,0x24,0x28,0x41,0x42,0x44,0x48,0x81,0x82,0x84,0x88
};
void Delay()
{
uchar i;
for(i=0;i<200;i++);
}
uchar Keys_Scan()
{
uchar sCode,kCode,i,k;
P1 = 0xf0;
if((P1&0xf0)!=0xf0)
{
Delay();
if((P1&0xf0)!=0xf0)
{
sCode = 0xfe;
for(k=0;k<4;k++)
{
P1 = sCode;
if((P1&0xf0)!=0xf0)
{
kCode = ~P1;
for(i=0;i<16;i++)
{
if(kCode == KeyCodeTable[ i])
return i;
}
}
else
sCode = _crol_(sCode,1);
}
}
}
return -1;
}
void main()
{
uchar KeyNO = -1;
uchar i,P2_LED,P3_LED;
while(1)
{
KeyNO = Keys_Scan();
if(KeyNO != -1)
{
P2_LED = 0xff;
P3_LED = 0xff;
for(i=0;i<=KeyNO;i++)
{
if(i<8)
P3_LED>>=1;
else
P2_LED>>=1;
}
P3 = P3_LED;
P2 = P2_LED;
}
}
}
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