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Re: ball-hours

Cross-posted to 2 groups.

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rickman wrote:
> On 10/15/2014 11:42 PM, Raimond Dragomir wrote:
>>>>                                    ... Your other post seemed to be
>>>
>>>> talking about bitbanging the I2S port to the CODEC.  How does that work
>>>
>>>> into the 100 MHz need?  Bitbanging a serial port of any kind can be CPU
>>>
>>>> cycle intensive.
>>>
>>>>
>>>
>>>
>>>
>>> Yes, it is a major concern. We might need to hang an FPGA in there at
>>>
>>> least for TX, as a buffer, because essentially we are writing sine
>>>
>>> waves. Doesn't work on RX though, that's time-varying stuff. I hope I2S
>>>
>>> works for us, somehow. Got to find out.
>>>
>> Probably I'm plain wrong because I don't know anything about your
>> application, but there are plenty ARM Corthex-M chips with I2S ports.
>> For example, my LPC4088 has I2S with internal FIFO, separate PLL, etc.
>> I can generate 48kHz 16bit audio stereo only with interrupts, no even
>> need for DMA. My system runs at 120MHz.
> 

Thanks. It doesn't mention TDM but could be a candidate if the
arbitration in the I2S section is efficient.

http://www.nxp.com/documents/data_sheet/LPC408X_7X.pdf


> You only replied in the c.l.f group so he won't likely see your
> response.  I'm sure he is reading this in the s.e.d group.
> 
> Some other devices have been mentioned to him already.  Joerg is an
> engineer with a lot of "preference".  He won't use MCU parts from a
> company he feels doesn't give good support so many of them are not in
> the running.  I know he has mentioned STM as a no-go.   I don't know
> about NXP.  I do know that NXP ARMs have a huge and very active
> community which can give good support.
> 

A community is great and very useful. However for a product in a
regulated market (on this one the FDA will have a say) sometimes it is
necessary to obtain a written statement from the manufacturer. End of
last year I had a case where NXP omitted something in the datasheet. It
took major rattling of the cage to obtain an answer. That left a sour
aftertaste.


> I find it interesting that he wants to use a CODEC with an I2S port
> which requires 8 channels (not always supported even if there is an I2S
> port), but hasn't considered that in his selection criteria until now.
> 

Well, I didn't start the search before yesterday and assumed that modern
ARM processors would have no problem with that. Now I know that some do.

-- 
Regards, Joerg

http://www.analogconsultants.com/

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Thread

Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-15 00:25 -0400
  Re: ball-hours bruce.person@gmail.com - 2014-10-14 23:51 -0700
    Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-15 03:15 -0400
  Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-15 05:36 -0700
    Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-15 16:22 -0400
      Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-15 16:12 -0700
        Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-15 22:48 -0400
          Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-16 11:21 -0700
            Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 15:24 -0400
              Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-16 13:37 -0700
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 17:42 -0400
                Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-17 07:14 -0700
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-17 14:03 -0400
                Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-17 12:03 -0700
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-17 15:23 -0400
                Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-17 12:44 -0700
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-17 18:37 -0400
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 20:59 -0400
                Re: ball-hours albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-10-17 08:43 +0000
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-17 13:53 -0400
                Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-17 07:50 -0700
        Re: ball-hours Raimond Dragomir <raimond.dragomir@gmail.com> - 2014-10-15 20:42 -0700
          Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 01:50 -0400
            Re: ball-hours Raimond Dragomir <raimond.dragomir@gmail.com> - 2014-10-16 00:49 -0700
              Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 05:14 -0400
            Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-16 11:58 -0700
        Re: ball-hours "Elizabeth D. Rather" <erather@forth.com> - 2014-10-16 08:32 -1000
          Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 15:32 -0400
          Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-16 13:45 -0700

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