Midi with Beaglebone

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1

I am trying to set the baud rate of one of the Beaglebone's serial
port to 31250, the baud rate for Midi. 31250 is a non-standard baud
rate and I am trying to write a simple program to set the rate for /
dev/ttyO1. The program outputs the "Error: could not set
custom_divisor" message, as ioctl returns -1 after the custom_divisor
has been set.

#define CUST_BAUD_RATE 31250

int main()
{
   int fd = open ("/dev/ttyO1", O_RDWR);
   if ( fd == -1 )
   {
      cout << "Error opening device" << endl;
      return -1;
   }

   struct serial_struct ser_info;
   int i = ioctl(fd, TIOCGSERIAL, &ser_info);
   if ( i < 0 )
      cout << "Error: could not get ioctl" << endl;

   ser_info.flags = ASYNC_SPD_CUST | ASYNC_LOW_LATENCY;
   ser_info.custom_divisor = ser_info.baud_base / CUST_BAUD_RATE;
   i = ioctl(fd, TIOCSSERIAL, &ser_info);
   if ( i < 0 )
      cout << "Error: could not set custom_divisor" << endl;

   close (fd);
   return 0;
}

Any suggestions?

2

Forget it, you'll need to hack up the kernel to get 31250. Better to use USB-MIDI instead (cables are cheap) as the default class driver works wonderfully.

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