單片機鍵盤(pán)掃描實(shí)驗

代碼如下：

//實(shí)例7

#include

//led字模

char led_mod[] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,

0x7f,0x6f,0x77,0x7c,0x58,0x5e,0x79,0x71};

//鍵值

char key_buf[] = {0x11,0x21,0x41,0x81,0x12,0x22,0x42,0x82,

0x14,0x24,0x44,0x84,0x18,0x28,0x48,0x88};

char getKey(void);

void delay(unsigned int time){

unsigned int j = 0;

for(;time>0;time--)

for(j=0;j<125;j++);

}

void main(void) {

char key = 0;

P2 = 0x00;

//P0=0x11;

while(1) {

key = getKey();

if (key != -1) {

P2 = led_mod[key];

}

delay(10);

}

}

//檢測按鍵

//返回-1表示沒(méi)有檢測到按鍵按下

char getKey(void) {

char i = 0;

unsigned char keycode=0xff;

unsigned char scancode=0xff;

scancode=0xf7;

P0=0xf0;

while(scancode!=0xff) {

P0=scancode;

//delay(10);

keycode=P0;

if((keycode&0xf0)!=0xf0)break;

scancode=(keycode>>1)|0xf0;

//if(keycode==0xff)scancode=scancode&0xf0;

}

keycode=~keycode;

for (i = 0 ; i < 16 ; i++) {

if (key_buf[i] == keycode) {

return i;

}

}

return-1;

}