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RE: [rtl] Interrupt latencies [newbie]



Dear J. Laako,

I have ever used RTLinux to acquire/logging Data Stream from Digital
Switching System (Telephone Office) through PPI 8255 home made card, the
data stream rate is 50 kByte/s ( 20us period interrupt ).

I made driver code as 'rt_process', and user program to get the data
from RT_FIFO, no data loss during high traffic on Harddisk and Network.
I configured them in Distributed Processing System.

>From my experience, Intel Pentium 100 is enough for this kind.

Regards,



<adolf@ratelindo.co.id>
OMC Switching Div
Wisma Bakrie Lt. 5,
Jl. HR. Rasuna Said Kav B1
Jakarta
Telp. 9101112 ext. 411

> ----------
> From: 	Jussi Laako[SMTP:rtl-list@jlaako.pp.fi]
> Sent: 	Wednesday, October 07, 1998 5:20 AM
> To: 	rtl@rtlinux.cs.nmt.edu
> Subject: 	[rtl] Interrupt latencies [newbie]
> 
> Hello,
> 
> Watning, this is kind of newbie question...
> 
> I'm planning to write RT-Linux 'driver' for ACL-8111 DAQ-card
> (ACL/PCL-711B
> compatible). It doesn't have FIFO-buffer, but generates iterrupts when
> AD
> conversion is ready. Maximum sampling rate is about 25 kHz. There's no
> timer
> for DA converter, it just changes state every time there is data
> written to
> it.
> 
> How fast computer I need (or is it at all possible) to reliably read
> data from
> card and write it to rtl-FIFO at 25 kHz interrupt rate? Operation
> would be
> about two IN operations, two OUT operations some simple integer math
> for
> internal buffer and write to rtl-FIFO about every 512 samples. No
> missed
> interrupts/lost data is allowed, because data is going to FFT
> analysis. System
> will have one machine sampling and sending data over (ethernet) socket
> connection to other machine for analysis.
> 
> If possible is there any chance to get steady 8192 Hz data out on DAC
> at same
> time?
> 
> ...or should I just spend twice the money and buy card with FIFO?
> 
> Thanks in advance,
> 
> 	- Jussi Laako
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