A/D电路图（ADC0804）
代码
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 }
