RE: [ECOS] context for creating interrupts on edb7312

[Gary Thomas <gary at mlbassoc dot com>]

On Thu, 2003-11-20 at 08:01, Aaron Case wrote:
> > It happens automatically in "cyg_start()", so my test runs just as well
> > even if I make this change:
> >
> > Index: hal/powerpc/mpc8xxx/current/tests/mpc8xxx_timer.c
> > ===================================================================
> > RCS file:
> > /home/gthomas/my_cvs/develop/ecos/packages/hal/powerpc/mpc8xxx/cur
> > rent/tests/mpc8xxx_timer.c,v
> > retrieving revision 1.1
> > diff -u -5 -p -r1.1 mpc8xxx_timer.c
> > --- hal/powerpc/mpc8xxx/current/tests/mpc8xxx_timer.c   20 Nov 2003
> > 14:21:54 -0000      1.1
> > +++ hal/powerpc/mpc8xxx/current/tests/mpc8xxx_timer.c   20 Nov 2003
> > 14:29:39 -0000
> > @@ -149,12 +149,12 @@ cyg_user_start( void )
> >      IMM->cpm_timers_trr1 = 0x2000;  // Reference value
> >      IMM->cpm_timers_tcn1 = 0;
> >      IMM->cpm_timers_ter[0] = 0xFF;
> >      IMM->cpm_timers_tgcr1 = _TC_TGCR_RST1;  // Reset & enable timer1
> >
> > -    cyg_scheduler_start();
> > -    CYG_TEST_PASS("mpc8xxx_timer");
> > +//    cyg_scheduler_start();
> > +//    CYG_TEST_PASS("mpc8xxx_timer");
> >  }
> >
> >  //
> > -------------------------------------------------------------------------
> >
> >  #else  // ! CYGPKG_KERNEL
> >
> > Are you overriding "cyg_start()"?  That's the place that the scheduler
> > is normally started (although many of our tests do it explicitly)
> >
> > --
> > Gary Thomas <gary@mlbassoc.com>
> > MLB Associates
> >
> >
> 
> Thanks for the clarification. I believe this may be my last question on the
> matter.
> 
> Is it possible to enable interrupts with cyg_interrupt_enable(), before the
> task scheduler starts, supposing I were foolish enough to do such a thing?
> 
> It appears that cyg_interrupt_enable() acts directly on the CPSR in
> ARM(after viewing the ASM), but my MAJIC debugger tells me that the CPSR
> doesn't change unless the scheduler is started. So what in eCos blocks
> access to the interrupt bits in the CPSR when the scheduler is not running?

Nothing - remember eCos is pretty light weight; you can do most anything
you want at any time.  That said, it's not a good idea to be messing 
around with the interrupts and you should never blindly just enable them
(unless you want a broken system!)

-- 
Gary Thomas <gary@mlbassoc.com>
MLB Associates


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