C51学习 之 A/D D/A

 1 #include <reg52.h>
 2 
 3 sbit wela = P2^7;
 4 sbit dula = P2^6;
 5 sbit dawr = P3^6;
 6 sbit dacs = P3^2;
 7 sbit beep = P2^3;
 8 
 9 void delay(unsignd int time)
10 {
11     while(time--);
12 }
13 
14 void init()
15 {
16     dula = 0;
17     wela = 0;
18     dacs = 0;
19     dawr = 0;
20     P0 = 0;
21 }
22 
23 int main()
24 {
25     unsigned char var,flag;
26     init();
27     while (1) {
28         if (flag == 0) {
29             val += 5;
30             P0 = val;
31         }
32         if (val == 255) {
33             flag = 1;
34             beep = 0;
35             delay(10000);
36             beep = 1;
37         }
38         delay(5000);
39     } else {
40         val -= 5;
41         P0 = val;
42         if (val == 0) {
43             flag = 0;
44             beep = 0;
45             delay(10000);
46             beep = 1;
47             
48         }
49         delay(5000);
50     }
51 }