Do you mean it's better because it can sample at a higher rate? So can mine,
but I need mine to sample exactly at 1kHz, so I have it reduced. Or did you
mean that his can sample exactly at 8000Hz? With no +/- variance in the sample
rate?
--- In Jim Jackson <> wrote:
>
>
>
>
> On Mon, 27 Jul 2009, tseredynski wrote:
>
> > Hm... could you tell me about how much more accurate the rate would be if
> > I used the kernel driver? I switched the the T4 timer, and now poll it
> > as it counts up until it is greater than a certain value (this way it
> > catches the value for sure, though maybe not exactly on but close). I am
> > aiming for a rate of 1kHz, and I get a value that ranges from about
> > 950-1000Hz. It no longer gets the large drops in sample frequency that I
> > got when trying with T3, but I'm still curious if this is as accurate as
> > I can get or whether using a kernel driver would enable me to achieve
> > something like a 995-1000Hz range.
>
> Phil's driver can sample at 8KHz, and it is good enough for sound sampling.
> Subjectivey this would imply the timer accuracy far better than your user
> land code.
>
> >
> > Thanks again for your help.
> >
> > --- In mike.mcdonald0@ wrote:
> >>
> >> You need to be able to catch the interrupt from the timer when it expires.
> >> The only way is with a driver of some kind. Polling the timer registers is
> >> not reliable especially if the countdown is very short.
> >>
> >> --- On Mon, 7/27/09, tseredynski <tseredynski@> wrote:
> >>
> >> From: tseredynski <tseredynski@>
> >> Subject: [ts-7000] Re: T3 timer use on TS-7200
> >> To:
> >> Received: Monday, July 27, 2009, 2:22 PM
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> Hi,
> >>
> >>
> >>
> >> Thanks for the response. Why exactly do I need to use a kernel driver?
> >> I'm not very familiar with them, and I don't usually like to use things
> >> that I don't understand well. I'm currently trying with T4 instead of T3
> >> and it's showing more promise of being reliable... but I'm not done yet.
> >>
> >>
> >>
> >> But I'd really like to know why I'm unable to make use of the timer with
> >> pure C programming. Thanks.
> >>
> >>
> >>
> >> --- In .com, Jim Jackson <jj@> wrote:
> >>
> >>>
> >>
> >>>
> >>
> >>> You really need to use a kernel driver for this.
> >>
> >>> For an example, check our Phil's ADC kernel module - it's in the file
> >>
> >>> section of the group. It uses one of the timers to schedule when to
> >>
> >>> read the ADC.
> >>
> >>>
> >>
> >>> On Fri, 24 Jul 2009, tseredynski wrote:
> >>
> >>>
> >>
> >>>> Hello,
> >>
> >>>>
> >>
> >>>> I'm trying to use the T3 timer on my Ts-7200 to execute a function at a
> >>>> constant 4khz rate (every 0.25 ms), but I'm running into trouble.
> >>
> >>>>
> >>
> >>>> I'm trying to do so by loading the appropriate value to the timer, and
> >>>> then constantly polling the T3 value, and waiting for it to hit 0.
> >>>> However, a few problems occur. First of all, it doesn't seem like my
> >>>> program can poll the value fast enough to catch the 0. The clock hits
> >>>> zero, and resets before my program can even get the value.
> >>
> >>>>
> >>
> >>>> It also seems that every couple of milliseconds (~5ms) I get a large
> >>>> delay. I checked this part by using printf() to display values as fast
> >>>> as it could and I'd usually get gaps of about 20 clock counts, however
> >>>> every couple of milliseconds I'd get a gap that was much larger (a
> >>>> couple hundred clock counts). Also, while trying to print values as
> >>>> fast as possible, it would usually print 20 values per cycle but every
> >>>> couple of cycles it would print closer to 30.
> >>
> >>>>
> >>
> >>>> This makes me think that there might be processes running on the board
> >>>> with higher priority than my program.
> >>
> >>>>
> >>
> >>>> Does anyone have some advice? Can I use the timer like I'm trying to, or
> >>>> do I need to try to use the interrupt request generated by the timer? (I
> >>>> don't know how to do this atm, so advice regarding that would be
> >>>> appreciated)
> >>
> >>>>
> >>
> >>>> Thank you!
> >>
> >>>>
> >>
> >>>>
> >>
> >>>
> >>
> >
> >
> >
>
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