on the am355x processor the ADC used is 12 bit SAR ADC with a sample
rate of 200 KSPS

any faster and you will need an external ADC


On 6/20/2016 12:53 PM, Micka wrote:
> the best woud be the PRU because you can store the data in the share
> memory. That is the fastest way.
>
> you can stop the acquisition whenever you want or let it go back at
> the beginning of your memory and go on.
>
>
> Le lun. 20 juin 2016 à 21:29, <[email protected]
> <mailto:[email protected]>> a écrit :
>
>     I'm looking to write a simple app for BBB.  When started from the
>     command line, it would set up the ADC in continuous mode and read
>     ~1 M samples from e.g. AN0 into memory.  After the capture is
>     complete, it would write the data to a file and exit.
>
>     Ideally, it would run at the hardware limit of 1.6 MSPS (15 cycles
>     of 24 MHz adc_clk per sample).  If that's not practical, 800 KSPS
>     or better would be acceptable.
>
>     What is an easy way to do this?  Most Beaglebone ADC examples
>     sample at kilohertz rates or slower.
>
>     This guide:
>     http://processors.wiki.ti.com/index.php/Linux_Core_ADC_User%27s_Guide
>     speaks of 200 KSPS.  What is the limitation here?
>
>     I've seen various suggestions to use the PRU, but don't understand
>     why.  I would think that since DMA would be required anyway, there
>     should be no requirement to otherwise access the hardware with
>     tight timing.  If PRU is indeed necessary, is there a suitable
>     example or tutorial?  (None of the libpruio built-in examples deal
>     with rapid sampling or large amounts of data.)
>
>     Any other ideas for a simple way to capture data fast will be
>     gratefully appreciated.
>
>     Thanks.
>
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