使用C进行串口通讯

Question

I am developing a software wherein I have to receive data via serial port. I am opening the port in canonical mode and setting the VEOL flag to 0X78 (hexadecimal). The problem I am facing is that read is exiting every time it receives byte value 0X0A in between. Can somebody help me in resolving this issue, I want read to block till I receive end byte as 0X78 . This is the code I have written so far

struct termios tio;
char buf[255];

int fd = open(MODEMDEVICE, O_RDWR | O_NOCTTY); 
if (fd <0) {
    perror(MODEMDEVICE);
    exit(−1); 
}

bzero(&tio, sizeof(tio));
tio.c_cflag = B115200 | CS8 | CLOCAL | CREAD;
tio.c_iflag = IGNPAR;
tio.c_oflag = 0;
tio.c_lflag = 1;
tio.c_cc[VEOL] = 0X78;

tcflush(fd, TCIFLUSH);
tcsetattr(fd,TCSANOW,&tio);


int read=read(fd,buf,255);

printf("Number of bytes read is %d\n",read);

Thank you in advance.

Answer 1

The manual page states:

VEOL (0, NUL) Additional end-of-line character (EOL). Recognized when ICANON is set.

So, it doesn't replace all end-of-line characters, it just adds one more, meaning 0xa is still active.

Don't send the wrong data, or filter them out in software.