Affordable Freescale DSP Board

Discussion in 'Effects and the DSP' started by Lex Nahumury, Sep 1, 2008.

  1. Lex Nahumury

    Lex Nahumury DH Senior Member

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    I thought this might be interresting to my fellow DSP enthousiasts;

    Symphony™ SoundBite - Affordable Audio DSP Development Kit Product Summary Page

    Comes with free dev tools!
    Debugging through JTAG via USB.

    Very affordable. I bought a couple early this year.
    The board is based on a member of the well known 56k DSP chip family
    and is equipped with decent AK codecs.

    While those who have worked with mot56k before can jump right in,
    there might be quite a learning curve for others.
    Compared to emu10kx the DSP56371's instruction set can be quite intimidating
    as is it's initialization and features.

    This thing is very fast.
    @48kHz I was able to squeeze several cascaded effect algoritmes like
    guitar amp moddeller + Cab.moddeller + Chorus + tremelo + delay + Reverb
    etc. into it without any dropouts.
    The onboard RAM however is quickly used up by the delay lines.

    Although you can program the DSP in C (comes with C compiler),
    assembler is still the way to go.

    /Lex.
     
  2. Max M.

    Max M. h/h member-shmember

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  3. Lex Nahumury

    Lex Nahumury DH Senior Member

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    Yes, I've seen that one but it wasn't available (still isn't??)
    Besides, I wanted an expandable board (host + LCD, knobs etc.)

    Btw; I'm still looking for a suitable (affordable) host processor board.
    Any suggestions?
     
  4. Russ

    Russ Well-Known Member

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    Cool stuff :)
    Thanks for the info.
     
  5. Max M.

    Max M. h/h member-shmember

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    For the features/affordability ratio i believe this Freescale's goody is just unbitable by now.
    (it's interesting how agressively they decided to get these old good Motorola 563 series back to the market - very good)
    I'd really wish i had this one a few years ago.
     
  6. Lex Nahumury

    Lex Nahumury DH Senior Member

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    I wunder if these devices use a host cpu for reading out those pots/controls and parameter calculation.
    I doubt it's all done in the dsp.
    Did you find any specs/technical info?
     
  7. Russ

    Russ Well-Known Member

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    I do not think so, that would seem to defeat the purpose of making it stomp box. From the info on that page, it sounds like it only needs to be connected to the PC for programming.
     
  8. Max M.

    Max M. h/h member-shmember

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    From what i've heard/read it has "some" MCU to handle this - but nothing in detail
    (just some "on-board Freescale microcontroller")
     
    Last edited: Sep 1, 2008
  9. Russ

    Russ Well-Known Member

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  10. Lex Nahumury

    Lex Nahumury DH Senior Member

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    Sorry, you misunderstood; most if not all such digital audio devices use a seperate build-in host cpu to support the DSP. (not a PC)
    Non audio tasks like MIDI interface, control readout and parameter calculation etc. are handled by that host cpu.

    PS:
    Yes, MCU actually since it has all the periphial components and RAM/ROM integrated.
     
  11. Russ

    Russ Well-Known Member

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    Yeah, sorry, I misunderstood the term host.
    In any case, the above document shows the MCU info (Flexis MC9S08JM).
     
  12. Lex Nahumury

    Lex Nahumury DH Senior Member

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    Ah yes see on page 6.
    That MC9S08JM MCU reads out those controls and more.
    Thanks for the doc.
    Now let's see if there's some affordable dev board for the MC9S08JM.
     
  13. Lex Nahumury

    Lex Nahumury DH Senior Member

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  14. Max M.

    Max M. h/h member-shmember

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    btw., Lex - just in case, what a specific purpose you need a MCU board for?
    (Actually, i've misread your question about "affordable host processor board" above - reading it as "DSP board" for some reason)

    Either way (if you're not limited to any specific arch. or manufacturer) - of course i'd recommend something ARM based. There're very inexpensive ARM chips/boards.
    For example, last year i used LPC2148 PROTOTYPE DEVELOPMENT BOARD (it's a clone of more expensive IAR Kit) - here in Moscow i got it just for $30. So far so good - it did its task (though i can't say the USB part of this particular Phillips 2148 chip is not weird :) ).
    Although - before going with ARM you will need to dig into compiler compatibility/availability stuff (as not every ARM chip/board is programmable with GCC and commercial ARM compilers are very expensive).
     
    Last edited: Sep 1, 2008
  15. Lex Nahumury

    Lex Nahumury DH Senior Member

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    Well, the Soundbite is great but does not have a host MCU.
    (currently I use a laptop as host for the soundbite)
    To make a complete standalone device I need a host MCU that does;
    - parameter calculations (filter coeffs & stuff)
    - control readout (pots, switches and dial encoders)
    - MIDI I/O
    etc. and it must come with C compiler.
    (i'm not going to do filter coeff math in assembler lol)

    Hey Max that ARM board looks perfect at firts glance!
    Is there a (free) compatible C compiler available?
     
  16. Max M.

    Max M. h/h member-shmember

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    Is there a (free) compatible C compiler available?

    As far as i can tell - yes. (search for something like "LPC2000+gcc" or so).
    Unfortunately - i can't say in detail (as i used a commercial compiler).

    Anyway - i mentioned this particular board just as an example (if you dislike this one for some reason). But speaking of microcontrollers (and especially of 32-bit ones) - it's no even doubt to go with ARM :)
    (There's quite wide choice of ARM chips/boards - so i'm sure sooner or later you'll find something that fits near perfectly)

    i'm not going to do filter coeff math in assembler lol)

    I assume that you're ready for no floating-point in MCUs :)
    (though actually with many compilers you'll be able to have some fp-emulation - it's still pain in the ass)
     
    Last edited: Sep 1, 2008
  17. Lex Nahumury

    Lex Nahumury DH Senior Member

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    Now that's the kinda info I like!
    No need to look further, ARM it is.
    Thanks.
     
  18. Lex Nahumury

    Lex Nahumury DH Senior Member

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    Why are those fpu emulations PITA? Incompleet, not accurate?
    I mean OK they are slower since they run in software, but sin(x) is still the same sin(x) from a programmers point of view right?
     
  19. Max M.

    Max M. h/h member-shmember

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    Welll, nothing serious - but, it's additional Flash/RAM overhead (may or may not be critical depending on their amount you have) and they're not just "slower" but "slooooow" :drool: (again may be just fine on >50MHz MCU - but still need extra care when being put into time-critical chains (turning knobs like a mad or controlling via MIDI or something might be considered as time-critical at certain point).

    but sin(x) is still the same sin(x) from a programmers point of view right?

    Not just "sin(x)" but "C conforming sin(x)" :) (e.g. supporting all those #infs, #nans etc., e.g. with extra overhead, though typically many fpe libraries allow a sort of fine-tuning of such stuff)

    Well, i think you won't have any problems with that ;)
    (Finally, if at some point one finds certain fpe function hindering he's not going to be frighted by finding/writing suitable approximation (not necessary less presice) right in fixed-point domain)
     
    Last edited: Sep 2, 2008
  20. Lex Nahumury

    Lex Nahumury DH Senior Member

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    Hmmm,. I see. In that case, performance and RAM usage could indeed be a real 'show stopper' here.
    I must say I was a little worried about that.

    Not afraid of doing so, but I was kinda hoping to avoid these kind of exercises.
     

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