[ts-7000] Re: Failure to read serial comm on TS-7300

["yetanotherdjmorris" <>]

I had a similar problem last week.
For whatever reason, I set c_cc[VMIN] and c_cc[VTIME] both to zero and it 
seemed to be getting responses.

--- In  "shusshinchi" <> wrote:
>
> As mentioned in the subject. I am not doing anything complicated at all.
> I merely connected a peripheral device to com2 (/dev/ttyAM1). My program
> then sends out a series of bytes out on com2 to the peripheral device
> and the device responds. However, my program gets nothing. "cat
> /dev/ttyAM1" shows nothing either. Below is a sample code that I have
> used to produce this problem. Is there anything that I need to set
> anywhere to enable the OS to receive data on the serial comm link?
> 
> int main ( int argc, char** argv )
> {
>      for ( short c = 0 ; c < argc ; ++c )
>          cout << "[" << c << "] " << argv[c] << endl ;
> 
>      int fd = open ( argv[1], O_RDWR | O_NOCTTY | O_NDELAY ) ;
>      termios port_settings ;
> 
>      cout << "fd = " << fd << endl ;
> 
>      memset ( &port_settings, 0, sizeof port_settings ) ;
>      cfsetispeed ( &port_settings, B9600 ) ;
>      cfsetospeed ( &port_settings, B9600 ) ;
> 
>      port_settings.c_cc[VMIN] = 0 ;
>      port_settings.c_cc[VTIME] = 10 ;
> 
>      port_settings.c_iflag &= ~ICRNL ;
> 
>      port_settings.c_lflag &= ~ICANON ;
> 
>      port_settings.c_cflag &= ~PARENB ;
>      port_settings.c_cflag &= ~CSTOPB ;
>      port_settings.c_cflag &= ~CSIZE ;
>      port_settings.c_cflag &= ~CRTSCTS ;
>      port_settings.c_cflag |= CS8 ;
>      port_settings.c_cflag |= CREAD ;
>      port_settings.c_cflag |= CLOCAL ;
> 
>      tcsetattr ( fd, TCSANOW, &port_settings ) ;
>      tcflush( f d, TCIOFLUSH ) ;
> 
>      char output[ ] = { 0x06, 0x01, 0x00, 0x00, 0x00, 0x10, 0x3c, 0x71 }
> ;
>      short charCount = 0 ;
>      char c ;
>      char cA[8] ;
>      int r ;
> 
>      memset ( cA, 0, 8 ) ;
> 
>      cA[7] = '\0' ;
> 
>      tcflush ( fd, TCIOFLUSH ) ;
>      write ( fd, output, 8 ) ;
> 
>      usleep ( 500000 ) ;
> 
>      cout << "Bytes read = " << ( r = read ( fd, cA, 7 ) ) << endl ; //
> this line fails to read anything
> 
>      tcflush ( fd, TCIOFLUSH ) ;
> 
>      if ( r == -1 )
>      {
>              switch ( errno )
>              {
>                  case EAGAIN : cout << "eagain" << endl ; sleep ( 1 ) ;
> break ;
>                  case EBADF : cout << "ebadf" << endl ; break ;
>                  case EFAULT : cout << "efault" << endl ; break ;
>                  case EINTR : cout << "eintr" << endl ; break ;
>                  case EINVAL : cout << "einval" << endl ; break ;
>                  case EIO : cout << "eio" << endl ; break ;
>                  case EISDIR : cout << "eisdir" << endl ; break ;
>                  default : cout << "errno = " << errno ;
>              }
>      }
> }
>




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