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Data capture on VC707 with fmcadc2

Question asked by ctrofin on Apr 20, 2015
Latest reply on Apr 25, 2015 by ctrofin

Hi all,


Following the guide at AD-FMCADC2-EBZ Quick Start Guide [Analog Devices Wiki] , and using iio_readdev, when trying to set the buffer size, using the '-b' option, to some bigger value, say 4096, iio_readdev gets stuck and never returns. When stoping it with Ctrl-C after 30-40 seconds, I got the "ERROR: Unable to dequeue block: Interrupted system call" message.


The complete command line I used is:

# iio_readdev -b 4096 -s 4096 iio:device0 voltage0 > data.bin

^CERROR: Unable to dequeue block: Interrupted system call

ERROR: Unable to allocate buffer



The ofending line seem to be in libiio, file local.c, line 341:


ioctl (fileno(f), BLOCK_DEQUEUE_IOCTL, &block)

where BLOCK_DEQUEUE_IOCTL if defined in the same file as:

#define BLOCK_DEQUEUE_IOCTL _IOWR('i', 0xa4, struct block)


In my application I need to be able to capture bursts of 1-2Meg of contiguous data from the ADC, any suggestion on how to fix the buffer allocation would be appreciated.


Thank you,