求助：XS128模拟iic通信采集MMA7455无应答信号 通信, start

fengtianzhifeng

1. void start() {
   
2. SDA=1;
   
3. delay1us();
   
4. SCL=1;
   
5. delay1us();
   
6. SDA=0;
   
7. delay1us();
   
8. SCL=0;
   
9. }
   
10. void end()
    
11. {
    
12. SDA=0;
    
13. delay1us();
    
14. SCL=1;
    
15. delay1us();
    
16. SDA=1;
    
17. delay1us();
    
18. }
    
19. void respons()
    
20. {
    
21. uchar i;
    
22. SCL=1;
    
23. delay1us();
    
24. outa=0;
    
25. delay1us();
    
26. while((SDA==1)&&(i<250))
    
27. i++;
    
28. SCL=0;
    
29. delay1us();
    
30. outa=1;
    
31. delay1us();
    
32. }
    
33. void write_byte(uchar date)
    
34. {
    
35. uchar i;
    
36. for(i=0;i<8;i++)
    
37. {
    
38. SCL=0;
    
39. delay1us();
    
40. if(date&0x80)
    
41. SDA=1;
    
42. else
    
43. SDA=0;
    
44. delay1us();
    
45. SCL=1;
    
46. delay1us();
    
47. date<<=1;
    
48. 
    
49. }
    
50. SCL=0;
    
51. delay1us();
    
52. SDA=1;
    
53. delay1us();
    
54. }
    
55. uchar read_byte()
    
56. {
    
57. uchar i,k;
    
58. SCL=0;
    
59. delay1us();
    
60. SDA=1;
    
61. delay1us();
    
62. outa=0;
    
63. delay1us();
    
64. for(i=0;i<8;i++)
    
65. {
    
66. SCL=1;
    
67. delay1us();
    
68. k=(k<<1)|SDA;
    
69. SCL=0;
    
70. delay1us();
    
71. }
    
72. outa=1;
    
73. return (k);
    
74. }
    
75. void write_add(uchar add,uchar date)
    
76. {
    
77. start();
    
78. write_byte(0x3a);
    
79. respons();
    
80. write_byte(add);
    
81. respons();
    
82. write_byte(date);
    
83. respons();
    
84. end();
    
85. }
    
86. uchar read_add(uchar add)
    
87. {
    
88. uchar date;
    
89. start();
    
90. write_byte(0x3a);
    
91. respons();
    
92. write_byte(add);
    
93. respons();
    
94. start();
    
95. write_byte(0x3b);
    
96. respons();
    
97. date=read_byte();
    
98. respons();
    
99. end();
    
100. return (date);
     
101. }

复制代码

fengtianzhifeng

程序貌似不应答~调试了很长时间了~就是不能出数据很着急请求大家给点意见谢谢了~下面是delay函数
void delay1us(void){
  uint a;
  for(a=6;a>0;a--) {
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
  }
}

fengtianzhifeng

哪位大神给弟弟我解释下啊~求你们了~困扰太长时间了~