Re: [Xenomai-help] Advice on clock sources for xenomai rtdm driver

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On 07/10/2011 11:41 PM, Carlos Eduardo de Brito Novaes wrote:
> Hello all.
> 
> I woud like to ask you some opinion about timers.
> I am slowly working on a real time driver for a acquisition board. It can be 
> configured for read up to 32 anaalog channels and has a internal timer that wil 
> start the conversion on a programmed time (its a 8254 timer) or the PC ca send 
> a command to start conversions to. Sadly, there is no interrupt generated by 
> this board, so if using the internal timer the driver has to keep polling some 
> io ports to check for data and if any, retrieve it.
> If I can setup a (precise) timer to trigger an interrupt, so I can start the 
> conversions and on a know time read back the data. But the interrupt rate 
> would be about 1K or a bit more, so RTC would not be a good idea, I think. I 
> also read about HPET but it seens to have issues with xenomai and also I read 
> that for some reason, some interupts would be lost. Do you guys recommend me 
> something? Should I stick with polling and set up some delays with 
> usleep_range or there is a good timer on PC boards and weel supported with 
> xenomai?

If you are writing an rtdm driver, why not using rtdm timers?
http://www.xenomai.org/documentation/xenomai-2.5/html/api/group__rtdmtimer.html

-- 
                                                                Gilles.