pic16f877a的AD实验学习

一、主函数

1. //采集AD值
2. #include <pic.h>
3. #include "ad.h"
4. #include "usart.h"
5. __CONFIG(0xFF32);
6. const uchar disp[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,
7. 0x07,0x7f,0x6f};
8. //延时函数
9. void delayms(uint x)
10. {
11. uint j,k;
12. for(j=x;j>0;j--)
13. for(k=110;k>0;k--);
14. }
15. //显示4位，低位数码管显示不正常
16. void display(uint x)
17. {
18. PORTD= disp[x/1000]|0x80;
19. PORTA= 0x10;
20. delayms(2);
21. PORTD= disp[x/100%10];
22. PORTA= 0x08;
23. delayms(4);
24. PORTD= disp[x/10%10];
25. PORTA= 0x04;
26. delayms(2);
27. PORTD= disp[x%10];
28. PORTA= 0x02;
29. delayms(2);
30. }
31. //初始化IO
32. void init()
33. {
34. TRISA = 0x01;            //RA0 input mode
35. TRISC = 0xff;                //RC output mode
36. TRISD = 0;
37. PORTC = 0x01;
38. ADCON0 = 0x41;            //ADCS1:ADCS0=01,AN0,,A/D On
39. ADCON1 = 0x8E;            //right justified,ADCS2=0,1110
40. delayms(10);
41. }
42. //获取AD值
43. uint getad()
44. {
45. uint adval;
46. float advalf;
47. GO = 1;
48. while(GO);
49. adval = ADRESH;
50. adval = adval<<8|ADRESL;
51. advalf = adval/1023.0*5.0;                //转换成电压
52. adval = (uint)(advalf*1000);            //转换成4位整型
53. return (adval);
54. }
55. void main()
56. {
57. uint i = 0;
58. uint temp;
59. init();
60. usart_init();
61. while(1)
62. {
63. temp = getad();
64. display(temp);
65. if(i == 100)
66. {
67. usart_tx(temp>>8);
68. usart_tx(temp);
69. i=0;
70. }
71. delayms(5);
72. i++;
73. }
74. }

二、usart函数

1. #include <pic.h>
2. #include "usart.h"
3. //串口初始化
4. void usart_init(void)
5. {
6. SPBRG = 0xC;                //波特率19200
7. TXSTA = 0x24;                //开启发送，高速模式
8. RCSTA = 0X90;                //使能TXRX引脚，接收到CREN直到被清零
9. RCIE = 0X1;                    //使能接受中断
10. GIE = 0X1;                    //开启总中断
11. PEIE = 0X1;                    //开启串口中断
12. }
13. void interrupt usart(void)
14. {
15. if(RCIE && RCIF)
16. {
17. TXREG = RCREG;            //返回接收的数据
18. }
19. }
20. void usart_tx(unsigned char date)
21. {
22. TXREG = date;
23. while(TRMT!=1);
24. }