linux UART 

  1 #include <stdio.h>
  2 #include <string.h>
  3 #include <sys/types.h>
  4 #include <errno.h>
  5 #include <sys/stat.h>
  6 #include <fcntl.h>
  7 #include <unistd.h>
  8 #include <termios.h>
  9 #include <stdlib.h>
 10 
 11 int set_opt(int fd,int nSpeed, int nBits, char nEvent, int nStop)
 12 {
 13     struct termios newtio,oldtio;
 14     if  ( tcgetattr( fd,&oldtio)  !=  0)
 15     {
 16         perror("SetupSerial 1");
 17         return -1;
 18     }
 19     bzero( &newtio, sizeof( newtio ) );
 20     newtio.c_cflag  |=  CLOCAL | CREAD;
 21     newtio.c_cflag &= ~CSIZE;
 22 
 23     switch( nBits )
 24     {
 25     case 7:
 26         newtio.c_cflag |= CS7;
 27         break;
 28     case 8:
 29         newtio.c_cflag |= CS8;
 30         break;
 31     }
 32 
 33     switch( nEvent )
 34     {
 35     case 'O':                     //奇校验
 36         newtio.c_cflag |= PARENB;
 37         newtio.c_cflag |= PARODD;
 38         newtio.c_iflag |= (INPCK | ISTRIP);
 39         break;
 40     case 'E':                     //偶校验
 41         newtio.c_iflag |= (INPCK | ISTRIP);
 42         newtio.c_cflag |= PARENB;
 43         newtio.c_cflag &= ~PARODD;
 44         break;
 45     case 'N':                    //无校验
 46         newtio.c_cflag &= ~PARENB;
 47         break;
 48     }
 49 
 50     switch( nSpeed )
 51     {
 52     case 2400:
 53         cfsetispeed(&newtio, B2400);
 54         cfsetospeed(&newtio, B2400);
 55         break;
 56     case 4800:
 57         cfsetispeed(&newtio, B4800);
 58         cfsetospeed(&newtio, B4800);
 59         break;
 60     case 9600:
 61         cfsetispeed(&newtio, B9600);
 62         cfsetospeed(&newtio, B9600);
 63         break;
 64     case 115200:
 65         cfsetispeed(&newtio, B115200);
 66         cfsetospeed(&newtio, B115200);
 67         break;
 68     default:
 69         cfsetispeed(&newtio, B9600);
 70         cfsetospeed(&newtio, B9600);
 71         break;
 72     }
 73     if( nStop == 1 )
 74     {
 75         newtio.c_cflag &=  ~CSTOPB;
 76     }
 77     else if ( nStop == 2 )
 78     {
 79         newtio.c_cflag |=  CSTOPB;
 80     }
 81     newtio.c_cc[VTIME]  = 0;
 82     newtio.c_cc[VMIN] = 0;
 83     tcflush(fd,TCIFLUSH);
 84     if((tcsetattr(fd,TCSANOW,&newtio))!=0)
 85     {
 86         perror("com set error");
 87         return -1;
 88     }
 89     printf("set done!\n");
 90     return 0;
 91 }
 92 
 93 int open_port(int fd,int comport)
 94 {
 95     char *dev[]={"/dev/ttySAC0","/dev/ttySAC1","/dev/ttySAC3","/dev/ttySAC4"};
 96     long  vdisable;
 97     if (comport==1)
 98     {    
 99         fd = open( dev[comport - 1], O_RDWR|O_NOCTTY|O_NDELAY);
100         if (-1 == fd)
101         {
102             perror("Can't Open Serial Port");
103             return(-1);
104         }
105         else
106         {
107             printf("%s .....\n", dev[comport - 1]);
108         }
109     }
110     else if(comport==2)
111     {    fd = open( dev[comport - 1], O_RDWR|O_NOCTTY|O_NDELAY);
112         if (-1 == fd)
113         {
114             perror("Can't Open Serial Port");
115             return(-1);
116         }
117         else
118         {
119             printf("%s .....\n", dev[comport - 1]);
120         }    
121     }
122     else if (comport==3)
123     {
124         fd = open( dev[comport - 1], O_RDWR|O_NOCTTY|O_NDELAY);
125         if (-1 == fd)
126         {
127             perror("Can't Open Serial Port");
128             return(-1);
129         }
130         else
131         {
132             printf("%s .....\n", dev[comport - 1]);
133         }
134     }
135     if(fcntl(fd, F_SETFL, 0)<0)
136     {
137         printf("fcntl failed!\n");
138     }
139     else
140     {
141         printf("fcntl=%d\n",fcntl(fd, F_SETFL,0));
142     }
143     if(isatty(STDIN_FILENO)==0)
144     {
145         printf("standard input is not a terminal device\n");
146     }
147     else
148     {
149         printf("isatty success!\n");
150     }
151     printf("fd-open=%d\n",fd);
152     return fd;
153 }
154 
155 int main(void)
156 {
157     int fd;
158     int nread,i;
159     char buff[]="Hello\n";
160 
161     if((fd=open_port(fd,3))<0)
162     {
163         perror("open_port error");
164         return;
165     }
166     if((i=set_opt(fd,115200,8,'N',1))<0)
167     {
168         perror("set_opt error");
169         return;
170     }
171     printf("fd=%d\n",fd);
172     while(1){
173         errno = 0;
174         nread=read(fd,buff,8);
175         if(0 < nread){
176             printf("nread=%d,%s\n",nread,buff);
177         }
178     }
179     close(fd);
180     return;
181 }

 

posted @ 2016-07-11 21:54  some day  阅读(218)  评论(0)    收藏  举报