Dear David Olofson,
Thank you for nice answer, of course this PPI 8225 card(using 8255 I/O chip
with Strobe Mode 1) and without Hardware FIFO/buffer. I only use RT_FIFO.
But if you have experience "What is the maximum Interrupt Frequencies of
RT_IRQ", tell me more.
Regards,
Adolfo
> -----Original Message-----
> From: David Olofson [SMTP:[EMAIL PROTECTED]]
> Sent: Friday, May 04, 2001 1:20 AM
> To: [EMAIL PROTECTED]
> Subject: Re: [rtl] Maximum Sample Rate using RTLINUX
>
> On Thursday 03 May 2001 05:49, Adolf Ahmad MS wrote:
> > Dear All,
> >
> > I need a help.....
> >
> > I have a problem during capture data stream with data rate(sampling) 782
> > kByte/s using PPI8255 Card(ISA Bus). To capture the data stream, i
> applied
> > IRQ triggering.
> >
> > But, some times many byte of data are lost. How many maximum transfer
> rate
> > on RTLINUX ?
>
> No maxmum transfer rate, really, but there are hardware limitations on the
>
> IRQ response times...
>
>
> > As info, there is no problem if applied this program to capture the data
> > stream with 100 kByte/S.
>
> 100 kHz isn't bad for anything with a "normal" CPU in it! You're spending
> most of the CPU cycles on context switching here, probably with an
> occasional
> latency peak when the cache is exhausted... (That would be the several
> lost
> bytes when you try to go beyond 100 kHz.)
>
>
> I *really* think you should consider using DMA, or at least some hardware
> buffering... General purpose CPUs really aren't suitable for this kind of
> interrupt frequencies.
>
> Isn't there some hardware FIFO or ISA DMA support on that card? (I don't
> know
> anything about the PPI8255...)
>
>
> //David
>
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> | A Free/Open Source Plugin API for Professional Multimedia |
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