请教:如何使用ioctl()控制波特率等参数?

guozhaojing

请教各位高手:我如何使用ioctl()控制串行口波特率,起始位,数据位,停止位,校验位等参数,也就是控制这些参数的ioctl()的参数是什么?

jerboa

举一个例子，参考一下。:-)

1. 
   
2. #include <sys/ioctl.h>
   
3. #include <string.h>
   
4. #include <fcntl.h>
   
5. #include <unistd.h>
   
6. #include <stdlib.h>
   
7. #include <stdio.h>
   
8. #include <termio.h>
   
9. #include <sys/time.h>
   
10. 
    
11. int fd;
    
12. char writebuf[128];
    
13. char readbuf[64];
    
14. 
    
15. void flush232();
    
16. int writegpib();
    
17. 
    
18. void flush232()
    
19. {
    
20. printf("in flush232\n");
    
21. ioctl(fd,TCFLSH, 0);
    
22. ioctl(fd,TCFLSH, 1);
    
23. }
    
24. 
    
25. int writegpib()
    
26. {
    
27. int n;
    
28. int retry =0;
    
29. 
    
30. printf("in writegpib writing %s\n",writebuf);
    
31. printf("length of writebuf: %d\n",strlen(writebuf));
    
32. do {
    
33.         n = write(fd,writebuf, strlen(writebuf));
    
34.         printf ("error = %d\n",errno);
    
35.         printf("wrote %d characters to %d\n",n,fd);
    
36. } while ((n<=0) && retry++ < 5);
    
37. retry = 0;
    
38. do {
    
39.         n = write(fd,"\r",1);
    
40.         printf ("error = %d\n",errno);
    
41.         printf("wrote %d characters to %d\n",n,fd);
    
42. } while ((n<=0) && retry++ < 5);
    
43. 
    
44. if (n<0) n = 0;
    
45. return n;
    
46. 
    
47. }
    
48. 
    
49. void
    
50. delay(int t) {
    
51. struct timeval tp,to;
    
52. struct timezone tzp;
    
53. 
    
54. printf("in delay for %d\n",t);
    
55. 
    
56. if (gettimeofday(&tp,&tzp) == 0) {
    
57.         to.tv_usec=tp.tv_usec+t;
    
58.         to.tv_sec=tp.tv_sec+(to.tv_usec/1000000);
    
59.         to.tv_usec%=1000000;
    
60.         while (tp.tv_sec < to.tv_sec) {
    
61.                 gettimeofday(&tp,&tzp);
    
62.         }
    
63.         while (tp.tv_usec < to.tv_usec && tp.tv_sec == to.tv_sec) {
    
64.                 gettimeofday(&tp,&tzp);
    
65.         }
    
66. } else {
    
67.         printf("gettimeofday failed\n");
    
68. }
    
69. }
    
70.                
    
71. void
    
72. main(void)
    
73. {
    
74. 
    
75. printf ("in  main()\n");
    
76. printf ("error = %d\n",errno);
    
77. 
    
78. struct termio term;
    
79. int stat = 1;
    
80. int n;
    
81. int retry = 0;
    
82. int flags;
    
83. 
    
84. do {
    
85.         printf("opening serial port\n");
    
86.         fd = open("/dev/tty00", O_RDWR|O_NONBLOCK, int(0));
    
87.         printf ("error = %d\n",errno);
    
88. } while ((fd<=0) && retry++ < 5);
    
89. 
    
90. if (fd < 0) {
    
91.         printf("failed to open serial port\n");
    
92.         stat = 0;
    
93. }
    
94. 
    
95. if (stat) {
    
96.         ioctl(fd,TCGETA, &term);
    
97.         printf ("error = %d\n",errno);
    
98.         term.c_iflag=(IGNPAR|IGNBRK|IXON|IXOFF);
    
99.         term.c_cflag=(B9600|HUPCL|CREAD|CS8);
    
100.         term.c_oflag=0;
     
101.         term.c_lflag=0;
     
102.         term.c_cc[4]=100;
     
103.         term.c_cc[5]=1;
     
104.         ioctl(fd,TCSETA, &term);
     
105.         printf ("error = %d\n",errno);
     
106.         ioctl(fd,TCFLSH, 2);
     
107.         printf ("error = %d\n",errno);
     
108. }
     
109. 
     
110. if (stat) {
     
111.         flush232();
     
112.         sprintf(writebuf,"id");
     
113.         if (!writegpib()) stat=0;
     
114.         delay(2000000);
     
115.         do {
     
116.                 printf("reading from fd(%d)\n",fd);
     
117.                 n = read(fd,readbuf,56);
     
118.                 printf ("error = %d\n",errno);
     
119.                 printf("read %d from fd(%d)\n",n,fd);
     
120.         } while ((n<=0) && retry++ < 5);
     
121. 
     
122.         printf("readbuf = %s\n",readbuf);
     
123. 
     
124.         if (n<=0) {
     
125.                 stat=0;
     
126.         } else {
     
127.                 if (strstr(readbuf,"GPIB")) {
     
128.                         printf("got GPIB\n");
     
129.                 }
     
130.         }
     
131. }
     
132. 
     
133. if (stat) {
     
134.         fcntl(fd,F_GETFL,&flags);
     
135.         flags=flags & (~O_NONBLOCK);
     
136.         fcntl(fd,F_SETFL,&flags);
     
137. } else {
     
138.         close(fd);
     
139. }
     
140. }
     

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