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Audio questions : i2s, dac, oversampling, PIC, FPGA ...

Discussion in 'Embedded' started by yannouch, Nov 30, 2004.

  1. yannouch

    yannouch Guest

    Hello,

    I have a board with an embedded PowerPC (mpc8241), on which there is
    no audio hardware. I want this board to have audio capabilities. I
    have serial ports, usb ... but no i2s, which is, from what I've
    understood from my previous readings, the bus needed to control a
    DAC.

    I'd like the sound data to be oversampled to 192kHz. (let's say I have
    a HDD connected to this board and it contains 44.1 kHz PCM data
    files.)

    Actually my idea is to do smthg like :

    MAINBOARD == i2s ==>(OVERSAMPLING?)===> DAC ===> Analog output

    with mainboard separated from the rest of the hardware, in order to be
    able to plug to it High-Fidelity/High-Quality Audio-DAC


    So my questions are :

    1. Where the oversampling must be done ? in processor ? with a
    dedicated hardware ? Before being sent to i2s bus ? after the firts
    device (DAC?) on i2s bus ?

    2. How can I get this mainboard to have i2s capabilities ? I've
    searched a bit, and I think I've understood I should use a dedicated
    microcontroller (PIC ? FPGA ?) attached to the main microprocessor.
    True ? If I have an i2s bus, can I have the audio DAC separated from
    main board, just linking them via the i2s wires ?

    3. where can I find some good quality Audio DAC kit, taking data from
    i2s bus, sending Analog audio to RCA plugs ?


    Thanks

    Yann
     
    yannouch, Nov 30, 2004
    #1
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  2. I2S is a protocol primarily designed for streaming sound between DAC
    and a host controller. Controlling of the DAC is usually done via
    another bus such as I2C, L3, microwire etc. So apart from making sure
    that you can do I2S for streaming, you should also consider an another
    bus to control the DAC.

    Search out the Philips Semiconductor site for info on the I2S.

    good luck.
     
    tehn yit chin, Nov 30, 2004
    #2
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  3. (yannouch) wrote in @posting.google.com:
    Maybe I'm missing something... But why not just use a USB sound card?
     
    Michael Noone, Nov 30, 2004
    #3
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