Help.....DSP on ARM9 or ARM7!!!!

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Dear Friends,

In my design I need to develope a DSP algorithm on one DSP processor an
then to interface same with ARM which is handling all the peripherals.

I am thinking if my DSP algorithm can be implemented on ARM or not...s
need you help. Right now I am using evaluation board of Texas DSK, s
taking the input from microphone is given to CODEC(A to D conversion
whose sampling freq is 32KHz.

I have to implement 8192 point FFT on real time sound data....
And also want to implement Low pass FIR filter on Real time sound dat
before doing FFT. So can this be implemented on ARM 9 platform??????
while pareallaly I want to interface one modem, IR receiver,key board, an
external memory with ARM. If possible please let me know which will be th
best ARM9 based chip to implement the same.

So is it possible to implement all this on ARM7 or ARM9 platform so wit
one processor only I will have my solution.
What chip should I use for A/D conversion with good sampling of sound.

Please help me.......
Thanks and Regards,

Jagdish.






Re: Help.....DSP on ARM9 or ARM7!!!!

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You need 16 bits or 2x12bits A2D.  I don't think there is 13 bits A2D.

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You need over 1GHz ARM, preferrable with muti-media instructions.

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What's wrong with DSP?

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Re: Help.....DSP on ARM9 or ARM7!!!!
I agree as well, a 8192 point FFT in realtime is going to need a lot of
horsepower. It is probably best to leave it to the DSP and have the
ARM7/9 control the DSP.


Re: Help.....DSP on ARM9 or ARM7!!!!

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An ARM7 takes 2Mhz to perform a 8192 complex Q15 FFT. ARM9E is twice as
fast.

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Your requirements add up to around 10Mhz on an ARM7. Unless power
consumption is key, no need for a DSP.

Wilco



Re: Help.....DSP on ARM9 or ARM7!!!!

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That's for doing one per second, which is unlikely for any reasonable
algorithm.

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DSPs are designed exactly for these things.

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Re: Help.....DSP on ARM9 or ARM7!!!!

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Without more detailed information it is reasonable to assume only one FFT
would be needed for each set of 8192 samples, ie. only 3.9 needed per
second. ARM7 goes up to 120Mhz, so it can handle around 50 complex
8192-point FFTs per second.

In another post you wrote:
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The fastest ARM (Cortex-A8) is about as fast as the TMS320C64x (TI's fastest
DSP). Exactly which audio codec needs _that_ much DSP power?

Wilco




Re: Help.....DSP on ARM9 or ARM7!!!!
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In support of  Wilco Dijkstra argument:

The FFT is O( n log2(n) ).

As a quick estimate,  at fs = 32KHz that's around 400.000 butterflies
per second if no overlap is needed (please corect me if I'm wrong).
That would not be a big problem to do on the ARM then.

The OP does not detail the FIR requirements, but with some luck
the system may allow the FIR to simply be a scaling of the FFT bins
 - in which case the FIR comes almost for free.

DJ
--



Re: Help.....DSP on ARM9 or ARM7!!!!
Hello,

I strongly disagree with (some of) the other posters:

- That processing won't need THAT much computational power as someone
mentioned (1GHz+ ARM9).
- Either case, DSPs are made for that sort of thing.

But, what if you need control processing, besides number crunching?
Here, a much more compact and flexible solution is desired.

I strongly recommend you to have a look at Analog Devices' Blackfin
family of processors. They have both computational (800+ MMACs) and
control capabilities, as well as nice set of peripherals: SDRAM
controller, USB, Ehternet, CAN, UARTs, Timers, RTC, core voltage
regulators, PPI, etc.

What you mention is exactly the kind of job that Blackfin was designed
for!

Regards,

JaaC


Re: Help.....DSP on ARM9 or ARM7!!!!
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Please include adequate context in your posts.  This can be done
even from the broken google usenet interface.

If you want to post a followup via groups.google.com, don't use the
broken "Reply" link at the bottom of the article.  Click on "show
options" at the top of the article, then click on the "Reply" at
the bottom of the article headers.

More details at: <http://cfaj.freeshell.org/google/
Also see <http://www.safalra.com/special/googlegroupsreply/

--
"The power of the Executive to cast a man into prison without
 formulating any charge known to the law, and particularly to
We've slightly trimmed the long signature. Click to see the full one.
Re: Help.....DSP on ARM9 or ARM7!!!!
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Hello,

Thanks for the reminder. I am the same poster (jaac). Getting used to
google, I forgot that option. Will keep it in my mind for later posts.

Regards,

JaaC



Re: Help.....DSP on ARM9 or ARM7!!!!
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Gee CB, pretty contentless post there.

If you're going to nag, at least make it on topic.
Most of us use threaded newsreaders, and have no problem following
the discussion.

--Gene


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