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Re: ball-hours

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rickman wrote:
> On 10/17/2014 10:14 AM, Joerg wrote:
>> rickman wrote:
>>> On 10/16/2014 4:37 PM, Joerg wrote:
>>>> rickman wrote:
>>>>>
>>>>> Each processor is very low power when running flat out, just 5 mW. 
>>>>> But
>>>>> they almost never run flat out.  Because they are asynchronous they
>>>>> spend most of their time stopped when they draw 0.0875 uW, yes, that's
>>>>> less than a tenth of a uW for each processor or just 12 uW for the
>>>>> whole
>>>>> chip.  The processors respond to stimuli in just nanoseconds, not
>>>>> 100's
>>>>> or even 10' but single digit nanoseconds.
>>>>>
>>>>> Trust me, power will not be a problem with this part.  It is a very
>>>>> different beast to program however.
>>>>>
>>>>
>>>> I wonder how that company is doing. I read about their products years
>>>> ago but never seen any in schematics and I get to see a lot of new
>>>> stuff
>>>> because some of my daily bread is EMC remedy.
>>>
>>> I think they are doing ok, but mainly because they have nearly zero
>>> overhead.  They don't pay any salaries so no need for layoffs.
>>>
>>
>> Wow. So they all work for free? How do they make a living?
> 
> I believe many of them are functionally retired and don't need to work.
>  Others work part time and do consulting.
> 

So I guess they are hoping the company some day lands it big, their
equity stake turns into pure gold and then they can buy a Cessna
Citation with a matching tropical island :-)

> 
>>>>> Every problem in your design is asking for an FPGA.
>>>>>
>>>>
>>>> Possible, but not sure yet. Maybe there is a bigger processor out there
>>>> with real I2S/TDM and enough support by the manufacturer.
>>>
>>> Yeah, maybe.  You can go with one of the Cortex A processors like they
>>> use in the Beagle board or Raspberry Pi.  Without the Linux OS they
>>> should so a decent job.  They have floating point for your FFTs as well.
>>>   That will help prevent too much rounding noise in the FFTs.
>>>
>>
>> Except the Sitaras in QFP have been obsoleted. But I'll find something.
> 
> Yeah, it will be hard to find anything more powerful in QFP.  Normally
> they need a high pin count which requires BGA.  All of the higher end
> devices I have seen use external memory which pushes the pin count over
> the top for QFP unless you can find one in a 208 pin QFP.
> 

It would be nice not to need external memory. Don't want this to turn
into a monster with an RTOS, its own government and all that.

[...]

                                      ... The market is
>>> *littered* with those.  I've seen a bazillion 18 bit SAR parts out
>>> there.  Even LT has them, your favorite company.  Why not use one of
>>> those?  They often have fantastic SNR and THD specs.
>>>
>>> How about an 8 channel, 16 bit ADC in one package?
>>>
>>> http://www.linear.com/product/LTC1867L
>>>
>>> Well, maybe not.  The SINAD is not so good.  What is the frequency of
>>> the signal you are looking at?  The ADC specs also depend on your input
>>> frequency.
>>>
>>
>> DC to 20kHz but that requirement can be dropped to 10kHz. Also, if I
>> really, really had to, I could replace one of the two DACs with a DDS
>> chip because that just generates a sine wave. But it complicates the SW
>> because such chips need their own SPI sermons in Swahili.
> 
> I don't see a DDS as being much more simple than a DAC with a lookup
> table.  What varies on the sine wave?  Does it have a slight frequency
> variation or amplitude?
> 

The sine wave is constant in normal operation, except during a sweep
phase at the start. So a DDS would greatly cut down on data volume.
During operation it would not require any data sent over the SPI.

> 
>>> The point is that if you can drop the I2S interface you have a lot more
>>> potential MCUs to choose from.
>>>
>>
>> Sure, if the CPU can manage to keep seven balls in the air and serve all
>> those SPI device at 48ksps.
> 
> I have no idea why you think that is a problem.  This isn't juggling.
> This is electronics design and driving data over a few SPI ports that
> can all be managed though one port is not at all hard.  I think you are
> missing the "CONVERT" signal.
> 

I know how the hardware goes, done a ton of SPI designs with
synchronicity requirements and they all work. What I am concerned about
is the barrage of data inside the CPU that wants in and out. Something
in there has to slosh that around. AFAIU in a TDM scenario it would
simply flow nicely in a serial fashion. But that's where I'd have to
hand it over to SW experts because I am not a programmer.

-- 
Regards, Joerg

http://www.analogconsultants.com/

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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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