something around 450kS/s

2015-09-22 12:47 GMT-03:00 Julian David Rath <[email protected]>:

> 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
> >> >
> >> > --
> >> > For more options, visit http://beagleboard.org/discuss
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> >
> >
> >
> >
> > --
> > Atenciosamente,
> > Antônio Albuquerque
> >
> > --
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-- 
Atenciosamente,
Antônio Albuquerque

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