【51】 4x4按键 code

#ifndef _KEYBOARD_H_#define _KEYBOARD_H_#include <8052.h>#include "types.h"#define keydata P1void delay(INT16U time){while (--time);}INT8U Key_Scan(void){INT8Ui,key;INT8Uk = 255;keydata = 0xF0;if (keydata != 0xF0){keydata = 0xFE;for (i = 0; i < 4; i++){key = keydata & 0xf0;switch (key){case 0xe0 :k = i;break;case 0xd0 : k = i + 4;break;case 0xb0 :k = i + 8;break;case 0x70 : k = i + 12;break;default   :;break;}keydata = (keydata << 1);if (k != 255)break;}keydata = 0xF0;while (keydata != 0xF0);return (k);}elsereturn 'E';}#endif