[ECOS] delay function

[ECOS] delay function

[Natarajan, Mekala (CTS)]

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> Hi Jesper,
>     In the below mail u have asked to use the us delay function for busy
> wait..Can u kindly tell which 
> ecos API to use.
> 
> regards,
> mekala
> 
> -----Original Message-----
> From:	Jesper Skov [SMTP:jskov@redhat.com]
> Sent:	Tuesday, January 16, 2001 6:21 PM
> To:	Pamulapati, Indrasena (CTS)
> Cc:	Jesper Skov; ecos-discuss@sources.redhat.com
> Subject:	RE: [ECOS] Suitability of eCos
> 
> >>>>> "Pamulapati," == Pamulapati, Indrasena (CTS)
> <pindrase@chn.cognizant.com> writes:
> 
> Pamulapati,> Hi Jesper, Yes, the tick duaration controls the kernel
> Pamulapati,> scheduler and I dont need scheduling at that rate.  But
> Pamulapati,> does'nt the tick duration also determine the smallest
> Pamulapati,> addressable time unit.  What i mean is:
> 
> Pamulapati,> Let us consider the duration of a tick to be a reasonable
> Pamulapati,> value of 10millisec.  Now, if I want to send some data
> Pamulapati,> at, say 20ms from the start of a reference point, I will
> Pamulapati,> give a delay of 2ticks from the reference point and as u
> Pamulapati,> mentioned send an interrupt to the driver after 2ticks.
> 
> If you want to busywait, use the uS delay function instead.
> 
> But as Björn Stenberg pointed out, you probably want a high-speed
> timer to driver things instead of relying on the kernel scheduler
> timer.
> 
> Pamulapati,> Jesper, actually I am quite a newbie wrt drivers and
> Pamulapati,> rtos's.  Can you elaborate on "Drivers doing IO should be
> Pamulapati,> driven separately, relying on device interrupts, not
> Pamulapati,> scheduler interrupts, for state transitions." based on
> Pamulapati,> the problem I mentioned above. I guess this may solve my
> Pamulapati,> problem.
>  
> 

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Re: [ECOS] delay function

[Jesper Skov]

>>>>> "Natarajan," == Natarajan, Mekala (CTS)
      <NMekala@chn.cognizant.com> writes:

>> Hi Jesper, In the below mail u have asked to use the us delay
>> function for busy wait..Can u kindly tell which ecos API to use.

It's a HAL function, available if HAL_DELAY_US is defined. It may not
be defined by all HALs, but I think it is by now.

Jesper