I think you are missing one important point. If you need to deal with
micro or even millisecond timing accuracy, you need a Real Time
Operating System, not Linux. Maybe you can install some of the
patches provided by TS to run a Real time kernel instead of the
regular Linux one. Then, you need to treat your data acquisition
tasks as real time.
If not, you will need a data acquisition card with timers and FIFO
buffers and take care of the timing issues in hardware. In this way,
you can read the FIFO using a standard Linux process.
Javier////
--- In "David Farrell" <>
wrote:
>
> --- In "Anouk Ahamitet" <snowcone27@>
wrote:
> >
> >
> > --- In "charliem_1216" <charliem_1216@>
> > wrote:
> >
> > >... Better to fix your A/D code so it is insensitive to system
load.
> >
> > We're working on it, but since ts-linux doesn't have very accurate
> > timers (minimum usleep() appears to be almost 10 MILLISECONDS and
the
> > min nanosleep() is about 3.5 MILLISECONDS) we're stuck doing a
busy wait
> > on the built-in microsecond timer on the TS-7800 in order to get
> > accurate (and fast) enough timing on our A/D operations (note:
we're
> > using a 3rd party A/D, not one of Technologic's because the TS
A/Ds
> > don't support the input voltage ranges we require and/or don't
have
> > enough resolution).
> >
>
> Why not look at A/D PC/104 boards like those at www.mesanet.com
> they have the timers on board and FIFOs.
>
> You may also be able to use the TS-7800 high res timer to measure
the
> exact time your sample was taken and interpolate to get the value of
> the reading for the time you want. Don't wait on the timer, just
read it.
>
> David.
>
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