NI_PCIDIO, demo/cmd : broken pipe error at over 2.4 MHz

Hello all.

I'm using ni pcidio32hs and want to acquire data at about 6.5 MHz (at least 
5 MHz) at 32 bit.  I'm testing with cmd program in demo and changed the 
frequency to see how fast it can go. Only changes that I've made to 'cmd.c' 
are N_CHANS (from 256 to 4) and frequency.  There's no error if frequency 
is less than 2.4 MHz. At over 2.4 MHz, however, it gives 'broken pipe' 
error.  I have "comedi-0.7.65" and "rtai-24.1.10" on Redhat 7.3.  I've also 
tried with 'comedi-0.7.66' and got the same error at 2.4 MHz.

My questions are

1) What this error exactly means ? It happens at the 
line  "ret=read(comedi_fileno(dev),buf,BUFSZ)".  It looks like it's not 
reading fast enough from driver to memory.  Is it card limitation or driver 
bug?

2) Is there a way to recover from this error without restarting the 
computer?  I've checked 'man 2 signal' but can't figure it out.

3) How can I make it work at faster frequency without getting 'broken pipe' 
error.
Has any of you succeed at higher speed (over 5 MHz) with this card 
(ni_pcidio32hs)?  If so, what changes did you make ?

Thanks for any help.

Hee

Received on 2003-01-30Z14:19:36