警报声音的简单产生警报声音的简单产生

#include<reg2051.h> #define K1 P3_2 #define K2 P3_3 #define K3 P3_4 #define K4 P3_5 #define sound P3_7 void delay(unsigned char x); void key(); unsigned char i; void main() { P1=0XFF; while(1) { if } void delay(unsigned char x) { } void key() { }