What is your planned sample frequency?

On Tue, Sep 22, 2015 at 4:50 PM, Antônio Albuquerque <[email protected]> wrote:
> Hello Julian
>
> Thank you for your fast reply.
> I am trying to use the same ADS8528 to read 48 channel of sensors using
> daisy-chain to get the information simultaneously.
> Definitely I appreciate if you can send me some code.
>
> Best regards,
> Antonio
>
>
> 2015-09-22 10:48 GMT-03:00 Julian David Rath <[email protected]>:
>>
>> Hej Antonio,
>>
>> I used the PRU to communicate with the BBB, which works quite good.
>> But datarates with more the 20 Mbit are not realistic since the PRUs
>> have a clock of 200 Mhz.
>> If you are interested I could prepare some code to release.
>>
>> bests,
>>
>> Julian
>>
>>
>> On Tue, Sep 22, 2015 at 2:52 AM,  <[email protected]> wrote:
>> > Hello Julian,
>> > I am having the same issue, could you let me know about the solution?
>> > Have
>> > you found some workaround to use BBB->SPI and ADS8528?
>> > Best regards
>> > Antonio
>> >
>> >
>> > Em segunda-feira, 10 de março de 2014 07:15:25 UTC-3, Julian David Rath
>> > escreveu:
>> >>
>> >> Hi,
>> >>
>> >> I just found out that this is a better place to ask my question, it
>> >> seams
>> >> like there is also a beaglebone Google group, little confusing. So here
>> >> my
>> >> cross-post:
>> >>
>> >> I'd like to connect 4 ADS8528[0] daisy-chained via SPI to a BBB. I want
>> >> to
>> >> test it in different iterations first I want to measure the 32 Analog
>> >> input
>> >> channels captured by the ADS8528s with 1kHz and at the end with 200kHz.
>> >> Those ADS8528 using 4 SPI Channels in daisy-chain mode. So I did some
>> >> calculations on the needed bandwidth:
>> >>
>> >> for 1Khz:
>> >> 12Bit * 32Channels * 4KHz = 384 Kbit/s
>> >>
>> >> On 4 SPI Channels that means:
>> >> 12* 32*1Khz = 96 Kbit/s per SPI channel
>> >>
>> >> for 200Khz:
>> >> 12Bit * 32Channels * 200KHz = 76.8 Mbit/s = 9.6MByte/s
>> >>
>> >> On 4 SPI Channels that means:
>> >> 76.8Mb/s /4 = 19.2 Mbit/s per SPI channel
>> >>
>> >> Now 2 things:
>> >>  * Should/Can I use the built-in SPI of the BBB or do I have to
>> >> implement
>> >> 4 channels SPI bus by hand (High datarates PRUSS I guess)?
>> >>  * Do you think the high datarates for the 200Khz are achievable?
>> >>
>> >> Thanks,
>> >>
>> >> /Julian
>> >>
>> >> [0]: http://www.ti.com/product/ads8528
>> >
>> > --
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>
>
>
>
> --
> Atenciosamente,
> Antônio Albuquerque
>
> --
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