6410 串口，没字节最高位自动给过滤了

sasinop

[code]

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <errno.h>

main()
{
int fd;
int i;
int len;
int n = 0;
int m=0;
unsigned char read_buf[256];
unsigned char write_buf[256];
struct termios opt;

write_buf[0]=0xFF;
fd = open("/dev/ttySAC2", O_RDWR | O_NOCTTY); //默认为阻塞读方式
if(fd == -1)
{
perror("open serial 0\n");
exit(0);
}

tcgetattr(fd, &opt);
cfsetispeed(&opt, B9600);
cfsetospeed(&opt, B9600);

if(tcsetattr(fd, TCSANOW, &opt) != 0 )
{
perror("tcsetattr error");
return -1;
}

opt.c_cflag &= ~CSIZE;
opt.c_cflag |= CS8;
opt.c_cflag &= ~CSTOPB;
opt.c_cflag &= ~PARENB;
//opt.c_cflag &= ~INPCK;
opt.c_cflag |= (CLOCAL | CREAD);
/*
opt.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
opt.c_oflag &= ~OPOST;
opt.c_oflag &= ~(ONLCR | OCRNL); //添加的
//ISTRIP

sasinop

1. 
   
2. 
   
3. #include <stdio.h>
   
4. #include <stdlib.h>
   
5. #include <unistd.h>
   
6. #include <sys/types.h>
   
7. #include <sys/stat.h>
   
8. #include <fcntl.h>
   
9. #include <termios.h>
   
10. #include <errno.h>
    
11. 
    
12. main()
    
13. {
    
14. int fd;
    
15. int i;
    
16. int len;
    
17. int n = 0;
    
18. int m=0;
    
19. unsigned char read_buf[256];
    
20. unsigned char write_buf[256];
    
21. struct termios opt;
    
22. 
    
23. write_buf[0]=0xFF;
    
24. fd = open("/dev/ttySAC2", O_RDWR | O_NOCTTY); //默认为阻塞读方式
    
25. if(fd == -1)
    
26. {
    
27. perror("open serial 0\n");
    
28. exit(0);
    
29. }
    
30. 
    
31. tcgetattr(fd, &opt);
    
32. cfsetispeed(&opt, B9600);
    
33. cfsetospeed(&opt, B9600);
    
34. 
    
35. if(tcsetattr(fd, TCSANOW, &opt) != 0 )
    
36. {
    
37. perror("tcsetattr error");
    
38. return -1;
    
39. }
    
40. 
    
41. opt.c_cflag &= ~CSIZE;
    
42. opt.c_cflag |= CS8;
    
43. opt.c_cflag &= ~CSTOPB;
    
44. opt.c_cflag &= ~PARENB;
    
45. //opt.c_cflag &= ~INPCK;
    
46. opt.c_cflag |= (CLOCAL | CREAD);
    
47. /*
    
48. opt.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
    
49. opt.c_oflag &= ~OPOST;
    
50. opt.c_oflag &= ~(ONLCR | OCRNL); //添加的
    
51. //ISTRIP
    
52.         opt.c_iflag &= ~(ICRNL | INLCR);
    
53. opt.c_iflag &= ~(IXON | IXOFF | IXANY); //添加的
    
54. */
    
55. 
    
56. opt.c_cc[VTIME] = 0;
    
57. opt.c_cc[VMIN] = 0;
    
58. 
    
59. tcflush(fd, TCIOFLUSH);
    
60. 
    
61. printf("configure complete\n");
    
62. 
    
63. if(tcsetattr(fd, TCSANOW, &opt) != 0)
    
64. {
    
65. perror("serial error");
    
66. return -1;
    
67. }
    
68. printf("start send and receive data\n");
    
69. 
    
70. while(1)
    
71. {
    
72. n = 0;
    
73. len = 0;
    
74. 
    
75. m = write(fd, write_buf, 1);
    
76. printf("write %02X chars\n",write_buf[0]);
    
77. 
    
78. while( (n = read(fd, read_buf, 1)) > 0 )
    
79. {
    
80.         printf("read len is %d \n ",n);
    
81. for(i = len; i < (len + n); i++)
    
82. {
    
83. write_buf[i] = read_buf[i - len];
    
84. }
    
85. len += n;
    
86. printf("recive char is :%02X \n", read_buf[0]);
    
87. }
    
88. 
    
89. sleep(2);
    
90. }
    
91. }
    

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将串口扩展板，的串口2 的 2 和3 短接，自发自收即

1. 
   
2. [root@FORLINX6410]# ./acom
   
3. configure complete
   
4. start send and receive data
   
5. write FF chars
   
6. write FF chars
   
7. read len is 1
   
8. recive char is :7F
   
9. write 7F chars
   
10. read len is 1
    
11. recive char is :7F
    
12. ^C
    
13. 
    

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结果就是，每个字节的最高位，自动给过滤了

代码中，变量是  无符号的，，应该没啥问题了，，硬件啥有啥特别注意的？

还是其他地方有啥没注意到呢？