On Fri, May 05, 2000 at 09:56:50AM +0200, Alexander Lichius wrote:
> Hi all,
>
> besides the thing with the zero period. shouldn't there be a call to
> pthread_wait_np() in the thread code routine "fun"? i am new to
> rt-linux and i only checked the examples coming with it and there i
> found in the parallel port example (which is very similar to this one)
> the stated call.
> am i right that in this case the task never waits for the next period?
Yes. Good spotting.
>
> bye
> alexander
>
>
> Friday, May 05, 2000, 12:46:55 AM, you wrote:
>
> yfc> On Thu, May 04, 2000 at 02:34:44PM -0400, Elliott Wolin wrote:
> >> Hi,
> >>
> >> I must be missing something fundamental. I don't know why the program below
> >> doesn't generate a single rectangular pulse on the parallel port with a width of
> >> 50 microsec. (rtlinux 2.2.13, PIII 450).
> >>
> >> Rather than the 2nd thread running 50 microsec after the 1st, it runs
> >> immediately after the 1st, giving 10 microsec pulses.
> >>
> >> How do you delay the startup of a thread?
>
>
> yfc> You gave them 0 period and RTL scheduler picked a semi-safe 10microseconds
> yfc> Try making the period 50000 -- see below.
>
> >>
> >>
> >> Sincerely,
> >> Elliott Wolin
> >>
> >>
> >>
>===================================================================================
> >>
> >>
> >> /* Produce a single rectangular pulse on parallel port */
> >>
> >> #include <asm/io.h>
> >> #include <rtl.h>
> >> #include <pthread.h>
> >>
> >> #define LPT_PORT 0x378
> >>
> >> pthread_t t1,t2;
> >>
> >>
> >> void *fun(void *arg) {
> >> outb((int)arg, LPT_PORT);
> pthread_wait_np(); // ??
> >> return(0);
> >> }
> >>
> >>
> >> int init_module(void) {
> >> pthread_create (&t1, NULL, fun, (void*)~0x0); /* rising edge */
> >> pthread_create (&t2, NULL, fun, (void*) 0x0); /* falling edge */
> >>
> >> /* pulse width is 50 microsec */
> >> pthread_make_periodic_np (t1, gethrtime(), 0); /* rising edge */
> yfc> 50000
> >> pthread_make_periodic_np (t2, gethrtime()+50000, 0); /* falling edge */
> yfc> 50000
>
> >>
> >> return(0);
> >> }
> >>
> >>
> >> void cleanup_module(void) {
> >> pthread_delete_np (t1);
> >> pthread_delete_np (t2);
> >> }
> yfc> Content-Description: Card for Elliott Wolin
>
>
>
>
>
> CU
> Alexander mailto:[EMAIL PROTECTED]
>
>
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