Comments/experiences sought on RTEMS4.6.0pre2 with MPC860

Chris Johns cjohns at
Tue Apr 29 22:02:15 UTC 2003

Erwin Rol wrote:
> I have the console on SCC4 but that shoudl work the same. I had a
> problem with the TERMIO stuff because it hardwires the speed at 9600 and
> my bootloader set it to 115000. The examples don't reset this and so it
> switches speed which my terminal program does like. I "fixed" this in n
> the source to set the termio speed to a different default. I also mailed
> a question about it but never got a answer.

What I do is a simple little bit of termios code somewhere in or close to 'main':

    * Make the stdin stream baud rate what we expect as a default.

   if (tcgetattr (STDIN_FILENO, &term) < 0)
     printf ("rtems-target-init: cannot get terminal attributes.\n");
      * No echo, no canonical processing.

     term.c_cflag &= ~(CSIZE | CBAUD);
     term.c_cflag |= CS8 | B19200;

     if (tcsetattr (STDIN_FILENO, TCSANOW, &term) < 0)
       printf ("rtems-target-init: cannot set terminal attributes\n");

>>The problem:
>>We can trace execution through the rtems code up to the  call to
>>rtems_initialize_executive_late(); then nothing.
> Where does it halt? look with a debugger, it is likely that it hangs in
> the fatal error handler. several things that like to go wrong are MMU
> pages layout, SDRAM timing, and passing some weird bootblock info. Try
> to step trough the sources with a debugger and see where it goes wrong
> cause "than nothing" is not a real technical description :-) is "than
> nothing" a endless loop or simply no terminal output, or a exception
> etc. 

Also the first context switch typically enables interrupts. It something is not 
set up correctly things fail.

Adding a user extension fatal error handler is a good tip.

  Chris Johns, cjohns at

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