Re: ni_atmio command read errors

From: David Carr <dc_at_dcarr.org> · Date: Mon, 29 Mar 2004 16:25:57 -0600

Frank,

Thanks for your help.  I just finished compiling the CVS tree and its 
seems to work.

-David Carr

David Carr wrote:

> Hi all,
>
> Due to a disk failure I've had to rebuild my capture machine.  I 
> installed comedi 0.7.68, comedilib 0.7.21 and rtai-3.0r3.  I'm using a 
> gentoo machine based on a vanilla kernel.org 2.4.25 kernel.  The 
> kernel I'm currently using is not rtai patched but I experienced the 
> same issues with a rtai kernel.  My aquisition card is a National 
> Instruments at-mio-16e-2.
>
> Analog reads of ch0 work correctly using the 'inp' and 'insn' comedi 
> demos.  If I use the command demo, 'cmd' with a number of reads less 
> than 1024 (ie: 1023) everything works too.  However if the number of 
> reads is 2048, the value '2048' will be returned 1024 times followed 
> by the correct data for the last 1024 times.  Longer reads repeat this 
> pattern with '2048' returned in multiples of 1024 and with the last 
> 1024 values being the correct data.  For example, a read of length 
> 5000 returns '2048' 4096 times followed by correct samples 904 times.  
> The only deviation from this pattern is with reads of length between 
> 1025 and 2048.  A read of length 1025 returns correct data for the 
> first 1024 values followed by '2048' 1024 times.  Note:  The buffer on 
> the card is 2048 bytes deep and the data appearing in groups of 1024 
> would be consistent with a half-full buffer read.
> I had this setup working with [not quite sure of the versions] comedi 
> 0.7.66, comedilib 0.7.20, kernel 2.4.23 and rtai 24.?  I thought that 
> I'd upgrade to the new versions since I had to rebuild the system.  
> What am I doing incorrectly?
>
> Thanks for any ideas,
> David Carr
> Rice University
>
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