当把主函数中的for循环换成如文本所示，为什么液晶显示屏不能动

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3. 用51单片机控制ADC0804，当拧动A/D旁边的电位器时，液晶显示屏的数字随之变化
4. #include<reg52.h>
5. #include<intrins.h>
6. #define uchar unsigned char
7. #define uint unsigned int
8. sbit dula=P2^6;
9. sbit wela=P2^7;
10. sbit lcden=P3^4;
11. sbit lcdrs=P3^5;
12. sbit key1=P3^6;
13. sbit key2=P3^7;
14. sbit adwr=P2^0;
15. sbit adrd=P2^1;
16. sbit INTR=P2^2;
17. int i,num=200;
18. uchar code table2[]="0123456789";
19. void delay(uchar z)
20. {
21. uchar x,y;
22. for(x=z;x>0;x--)
23. for(y=110;y>0;y--);
24. }
25. void write_com(uchar com)
26. {
27. lcdrs=0;
28. P0=com;
29. delay(5);
30. lcden=1;
31. delay(5);
32. lcden=0;
33. }
34. void write_date(uchar date)
35. {
36. lcdrs=1;
37. P0=date;
38. delay(5);
39. lcden=1;
40. delay(5);
41. lcden=0;
42. }
43. void init()
44. {
45. dula=0;
46. wela=0;
47. write_com(0x38);
48. write_com(0x0c);
49. write_com(0x06);
50. write_com(0x01);//液晶初始化
51. write_com(0x80+0x40);//第二行显示电压
52. write_date(0x55);
53. write_date(0x3a);
54. }
55. void adinit()//启动ad转换函数
56. {
57. adwr=1;
58. _nop_();
59. adwr=0;
60. _nop_();
61. adwr=1;
62. }
63. void main()
64. {
65. uchar A1,B1,C1,D1,a,adval;
66. init();
67. while(1)
68. {
69. adinit();
70. delay(50);
71. adrd=0;
72. adval=P1;
73. _nop_();
74. adrd=1;
75. A1=adval/1000;
76. B1=adval%1000/100;
77. C1=adval%100/10;
78. D1=adval%10;
79. for(a=10;a>0;a--) 换成 \\\\write_com(0x80+0x42);
80. { \\\\write_date(table2[A1]);
81. write_com(0x80+0x42);
82. write_date(table2[A1]); \\\\\write_date(table2[B1]);
83. write_date(table2[B1]);
84. write_date(table2[C1]); \\\\\write_date(table2[C1]);
85. write_date(table2[D1]); \\\\\write_date(table2[D1])
86. }

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