c 串口读写数据实例解析

一 前记

程序员就是不断地砌砖头，然后用砖头，把砖头模块化，用的时候直接调用，能够节省很多精力。

二 实例：

 1 #include <stdio.h>
 2 #include <unistd.h>                     //Used for UART
 3 #include <fcntl.h>                      //Used for UART
 4 #include <termios.h>                    //Used for UART
 5
 6 typedef unsigned char uint8;
 7
 8 void dump8(uint8 *buf, int len)
 9 {
10         for(int icnt = 0; icnt < len; icnt++)
11         {
12                 printf("0x%x,",buf[icnt]);
13         }
14
15         printf("\n\t");
16 }
17
18
19 int main(void)
20 {
21         int data_num = 0;
22
23         printf("\nUART test\n\n");
24
25         int uart0_filestream = -1;
26
27         uart0_filestream = open("/dev/ttyUSB3", O_RDONLY | O_NOCTTY | O_NDELAY);                //Open in non blocking read/write mode
28         if (uart0_filestream == -1)
29         {
30                 printf("Error - Unable to open UART.  Ensure it is not in use by another application\n");
31                 return -1;
32         }
33
34
35         struct termios options;
36         tcgetattr(uart0_filestream, &options);
37         options.c_cflag = B921600 | CS8 | CLOCAL | CREAD;         //<Set baud rate
38         options.c_iflag = IGNPAR;
39         options.c_oflag = 0;
40         options.c_lflag = 0;
41         tcflush(uart0_filestream, TCIFLUSH);
42         tcsetattr(uart0_filestream, TCSANOW, &options);
43
44         printf("init complete, listening...\n\n");
45
46
47         while(1)
48         {
49
50         if (uart0_filestream != -1)
51         {
52                 unsigned char buf1[2];
53                 int n = read(uart0_filestream, buf1, 2);
54                 if ((n > 0) && (buf1[0] == 0xff) &&(buf1[1] == 0xff))
55                 {
56                         unsigned char buf2[2];
57                         dump8(buf1,2);
58                         n = read(uart0_filestream, buf2, 2);
59                         dump8(buf2,2);
60                         if (n > 0 && (buf2[0] == 0x40) &&(buf2[1] == 0x01))
61                         {
62
63                                 unsigned char buf3[640];
64
65                                 data_num = read(uart0_filestream, buf3, 640);
66
67                                 if(data_num > 0)
68                                 {
69
70                                         dump8(buf3,data_num);
71                                 }
72
73                         }
74                 }
75
76         }
77
78         }

三 总结：

运行一下，就知道结果了。