android串口通信发送at指令,一个串口通信程序，适用于3g模块发送简单AT指令

#include

#include

#include

#include

#include

#include

#include

#include

#include

int tty_fd;

int max(int a,int b)

{

return a>b?a:b;

}

int set_opt(int fd,int nSpeed, int nBits, char nEvent, int nStop)

{

struct termios newtio,oldtio;

if ( tcgetattr( fd,&oldtio) != 0)

{

perror("SetupSerial 1");

return -1;

}

bzero( &newtio, sizeof( newtio ) );

newtio.c_cflag |= CLOCAL | CREAD;

newtio.c_cflag &= ~CSIZE;

switch( nBits )

{

case 7:

newtio.c_cflag |= CS7;

break;

case 8:

newtio.c_cflag |= CS8;

break;

}

switch( nEvent )

{

case ‘O‘: //奇校验

newtio.c_cflag |= PARENB;

newtio.c_cflag |= PARODD;

newtio.c_iflag |= (INPCK | ISTRIP);

break;

case ‘E‘: //偶校验

newtio.c_iflag |= (INPCK | ISTRIP);

newtio.c_cflag |= PARENB;

newtio.c_cflag &= ~PARODD;

break;

case ‘N‘: //无校验

newtio.c_cflag &= ~PARENB;

break;

}

switch( nSpeed )

{

case 2400:

cfsetispeed(&newtio, B2400);

cfsetospeed(&newtio, B2400);

break;

case 4800:

cfsetispeed(&newtio, B4800);

cfsetospeed(&newtio, B4800);

break;

case 9600:

cfsetispeed(&newtio, B9600);

cfsetospeed(&newtio, B9600);

break;

case 115200:

cfsetispeed(&newtio, B115200);

cfsetospeed(&newtio, B115200);

break;

default:

cfsetispeed(&newtio, B9600);

cfsetospeed(&newtio, B9600);

break;

}

if( nStop == 1 )

{

newtio.c_cflag &= ~CSTOPB;

}

else if ( nStop == 2 )

{

newtio.c_cflag |= CSTOPB;

}

newtio.c_cc[VTIME] = 0;

newtio.c_cc[VMIN] = 0;

tcflush(fd,TCIFLUSH);

if((tcsetattr(fd,TCSANOW,&newtio))!=0)

{

perror("com set error");

return -1;

}

// printf("set done!\n");

return 0;

}

int open_port(int fd,int comport)

{

// char *dev[]={"/dev/ttyS0","/dev/ttyS1","/dev/ttyS2"};

// long vdisable;

if (comport==0)

{

//printf("open /dev/ttyUSB0");

fd = open( "/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_NDELAY);

if (-1 == fd)

{

perror("Can‘t Open Serial Port");

return(-1);

}

else

{

// printf("open ttyUSB0 .....\n");

}

}

else if(comport==1)

{ fd = open( "/dev/ttyUSB1", O_RDWR|O_NOCTTY|O_NDELAY);

if (-1 == fd)

{

perror("Can‘t Open Serial Port");

return(-1);

}

else

{

// printf("open ttyUSB1 .....\n");

}

}

else if (comport==2)

{

fd = open( "/dev/ttyUSB2", O_RDWR|O_NOCTTY|O_NDELAY);

if (-1 == fd)

{

perror("Can‘t Open Serial Port");

return(-1);

}

else

{

// printf("open ttyUSB2 .....\n");

}

}

if(fcntl(fd, F_SETFL, 0)<0)

{

printf("fcntl failed!\n");

}

else

{

//printf("fcntl=%d\n",fcntl(fd, F_SETFL,0));

}

if(isatty(STDIN_FILENO)==0)

{

printf("standard input is not a terminal device\n");

}

else

{

// printf("isatty success!\n");

}

// printf("fd-open=%d\n",fd);

return fd;

}

int main(int argc, char *argv[])

{

int maxfd;

fd_set rd;

int nread,i;

char tmp_buff[8];

char buff[1024];

char send_buf[1024];

int offset;

char recvbuf[1024];

struct timeval timeout={0,50000};

int timeout_flg = 0;

int recv_flg = 0;

// pthread_t check_ack_thread;

// pthread_attr_t check_ack_thread_attr;

if((tty_fd=open_port(tty_fd,1))<0)

{

perror("open_port error");

return 0;

}

if((i=set_opt(tty_fd,115200,8,‘N‘,1))<0)

{

perror("set_opt error");

return 0;

}

// printf("fd=%d\n",tty_fd);

FD_ZERO(&rd);

strcpy(send_buf,argv[1]);

// printf("uart >> ");

send_buf[strlen(send_buf)] = ‘\r‘;

send_buf[strlen(send_buf) + 1] = ‘\n‘;

send_buf[strlen(send_buf) + 2] = 0;

write(tty_fd, send_buf, strlen(send_buf));

memset(send_buf,0,sizeof(send_buf));

FD_SET(tty_fd, &rd);

FD_SET(fileno(stdin), &rd);

maxfd = max(fileno(stdin), tty_fd) + 1;

if(select(maxfd, &rd, NULL,NULL,NULL) < 0) {

perror("select error\n");

}

if(FD_ISSET(tty_fd, &rd)){

while((nread = read(tty_fd, buff, sizeof(buff))) > 0)

{

printf("%s", buff);

memset(buff, 1 , sizeof(buff));

}

exit(1);

}

close (tty_fd);

return 0;

}