rtems_wake_after

Fabio Degiovanni - Eicas degiovanni at eicas.it
Fri Jun 20 14:34:47 UTC 2003


Dear Jarry Needell,
                                I think you were right: it is a problem 
of overflow. I tried with CONFIGURE_MICROSECONDS_PER_TICK 1000 and 
rtems_task_wake_after(1000). The problems is at the 305th iteration. I 
tried to put the directive rtems_clock_get( 
RTEMS_CLOCK_GET_TICKS_SINCE_BOOT, &inter ); to see at what time (in 
ticks this happens) and I found out at 305266 ticks.
I don't understand what variables is subjected to overflow. I'm used to 
Linux real-time: in that case there is a periodic interrupt timer that 
is loaded to the value of MICROSECONDS_PER_TICK 1000, it counts down 
till 0 then it gives an interrupt, the interrupt service routine 
increment the value of ticks an reset the PIT to the 
MICROSECONDS_PER_TICK value. If RTEMS follows nearly the same procedure 
I don't see any point in which an overflow can occur. How does RTEMS 
work? What the variable that is subject to overflow? Why?
Thank you very much for your help

Fabio Degiovanni

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Eicas Automazione
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