说明：

RS232_D1，在Linux中的设备名称：/dev/ttyO3;

RS232_D2，在Linux中的设备名称：/dev/ttyO4

1、RS232是全双工通信，支持同时收发，所以只要将Tx与Rx 相接，回环测试串口

2、测试RS232_D2进入相应目录下测试 ./ttytest /dev/ttyO4

3、看到以下图片，说明能支持收发

附上源码作参考：

#define TRUE 1

#define FALSE -1

int

speed_arr[] = {B115200, B38400, B19200, B9600, B4800, B2400, B1200,

B300,

B38400, B19200, B9600, B4800, B2400, B1200, B300,

};

int

name_arr[] = {115200, 38400, 19200, 9600, 4800, 2400, 1200,

300,

38400, 19200, 9600, 4800, 2400, 1200, 300, };

void

set_speed(int fd, int speed)

{

int

i;

int

status;

struct termios Opt;

tcgetattr(fd, &Opt);

for (

i= 0; i < sizeof(speed_arr) / sizeof(int);

i++)

{

if

(speed == name_arr[i])

{

tcflush(fd, TCIOFLUSH);

cfsetispeed(&Opt, speed_arr[i]);

cfsetospeed(&Opt, speed_arr[i]);

status = tcsetattr(fd, TCSANOW, &Opt);

if

(status != 0)

perror("tcsetattr fd1");

return;

}

tcflush(fd,TCIOFLUSH);

}

}

int

set_Parity(int fd,int databits,int stopbits,int

parity)

{

struct termios options;

if (

tcgetattr( fd,&options) != 0)

{

perror("SetupSerial 1");

return(FALSE);

}

options.c_cflag &= ~CSIZE;

switch (databits)

{

case

7:

options.c_cflag |= CS7;

break;

case

8:

options.c_cflag |= CS8;

break;

default:

fprintf(stderr,"Unsupported data size\n");

return (FALSE);

}

switch (parity)

{

case

'n':

case

'N':

options.c_cflag &= ~PARENB;

options.c_iflag &= ~INPCK;

options.c_iflag &= ~(ICRNL|IGNCR);

options.c_lflag &= ~(ICANON );

break;

case

'o':

case

'O':

options.c_cflag |= (PARODD | PARENB);

options.c_iflag |= INPCK;

break;

case

'e':

case

'E':

options.c_cflag |= PARENB;

options.c_cflag &= ~PARODD;

options.c_iflag |= INPCK;

break;

case

'S':

case

's':

options.c_cflag &= ~PARENB;

options.c_cflag &= ~CSTOPB;

break;

default:

fprintf(stderr,"Unsupported parity\n");

return (FALSE);

}

switch (stopbits)

{

case

1:

options.c_cflag &= ~CSTOPB;

break;

case

2:

options.c_cflag |= CSTOPB;

break;

default:

fprintf(stderr,"Unsupported stop bits\n");

return (FALSE);

}

if

(parity != 'n')

options.c_iflag |= INPCK;

options.c_cc[VTIME] = 150; // 15 seconds

options.c_cc[VMIN] = 0;

tcflush(fd,TCIFLUSH);

if

(tcsetattr(fd,TCSANOW,&options) != 0)

{

perror("SetupSerial 3");

return (FALSE);

}

return (TRUE);

}

int

OpenDev(char *Dev)

{

int

fd = open( Dev, O_RDWR ); //| O_NOCTTY |

O_NDELAY

if

(-1 == fd)

{

perror("Can't Open Serial Port");

return -1;

}

else

return fd;

}

int

main(int argc, char **argv)

{

int

fd;

int

nread;

char

buffer[512];

//char *dev ="/dev/ttySAC1";

int

n=0,i=0;

const

char* dev = NULL;

dev =

argv[1];

if(dev==NULL)

{

printf("Please input seria device name ,for exmaple

/dev/ttyO1.\nNote:This is loop test application. Make sure that

your serial is loop\n");

return 0;

}

fd =

OpenDev(dev);

if

(fd>0)

set_speed(fd,115200); //设置波特率

else

{

printf("Can't Open Serial Port!\n");

exit(0);

}

if

(set_Parity(fd,8,1,'N')== FALSE) //设置传递参数

{

printf("Set Parity Error\n");

exit(1);

}

printf("\nWelcome to TTYtest\n\n");

memset(buffer,0,sizeof(buffer));

char

test[100]="forlinx am335x uart test......";

write(fd, test, strlen(test));

printf("Send test data------%s\n",test);

while(1)

{

nread

= read(fd,&buffer[n],1);

printf("read char is %c \n",buffer[n]);

if

(strlen(buffer)==strlen(test))

{

printf("Read Test Data finished,Read Test Data

is-------%s\n",buffer);

memset(buffer,0,sizeof(buffer));

printf("Send test data

again------%s\n",test);

write(fd, test, strlen(test));

n=0;

sleep(1);

continue;

}

n++;

}

}