一种单片机独立按键检测思路

#include

main()

{

unsigned char sw;

//unsigned char P1;

//unsigned char P3;

unsigned int t;

while(1)

{

sw=P3|0xf0;

switch(sw)

{

case 0xfe:P1=0xfe;

break ;

for (t=0;t<60000;t++);

case 0xfd:P1=0xf9;

for (t=0;t<60000;t++);

break;

case 0xfb:P1=0xc7;

break;

case 0xf7:P1=0x0f;

for (t=0;t<60000;t++);

break;

default: P1=0xff;

for (t=0;t<60000;t++);

break;

}

}

}