On Monday 04 December 2006 07:24, Vucsics Krisztian wrote: > Hello Everybody, > > I've checked the RT_PREEMPT_HOWTO but there is no "Hello World" example > at the moment. I don't know, whether and how it is possible to send > something via the serial port exactly scheduled, "without changing the > given programming APIs". I would like to send at least a single 'H' :-) > to a given serial port, precisely scheduled. > > Could you please send me an example for that?
The general approach would be to setup an event that wakes a thread to do the writing to the serial port at a specific time. There are several ways to accomplish this. The simplest approach would be to check the time using clock_gettime() (using CLOCK_MONOTONIC) and then sleep for the exact interval between that time and the time you want to write your 'H' using clock_nanosleep (again with CLOCK_MONOTONIC). The clock routines have nanosecond resolution (and probably 10s of microsecond accuracy, depending on your platform). When you wakeup, write the 'H', then repeat to schedule the next write. There are certainly more advanced approaches using pthread_cond_wait() and pthread_cond_signal() from master and slave threads, etc. > > Thank you in advance, > Krisztian > > > - > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" > in the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Darren Hart IBM Linux Technology Center Realtime Linux Team - To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
