Re: Update on continuous aquisitions

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On Saturday 03 April 2004 03:46 pm, David Carr wrote:
> I switched cards today from the at-mio-16e-2 to an at-mio-16e-1.   The
> new card exhibited a similar problem but shed a little bit more light on
> the problem.  The new card has a 8192 sample buffer instead of the
> previous card's 2048 sample buffer.  It only aquired for 16384 calls to
> read(comedi_fileno(dev),(void *)data,8192) compared to the previous
> card's 65536.  This meant to me that its not the number of calls to
> read() that causes the problem but instead the problem occurs after
> 2^27  bytes have been transferred from the card (ie: after 2^26 samples
> [at 2 bytes/sample]).  The scan counter on the board is only 24 bits and
> a look at the driver code leads me to believe that the continuous
> aquisition bit on the card is being set.  This seems not to sugguest
> that the on-board scan counter is simply stopping the card.

Well, if you're doing scans of 4 channels then 2^26 samples would 
correspond to the 24 bit scan counter rolling over.

- -- 
Frank

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Received on 2004-04-04Z01:11:06