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Using DMA with DCI for I2S driver question

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Thom7724
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2019/07/16 10:13:34 (permalink)
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Using DMA with DCI for I2S driver question

To start off I am pretty new to this stuff(student). What I am trying to accomplish is playing a WAV file. So step one was use DMA and learn how to implement a I2S driver. I dove into exploring the examples to better understand how to accomplish this. After looking through the example CE117 I just don't understand what the purpose of toggling the pin. Also I am going to be using a dsPIC33FJ128GP802 or 804 and there is no RA6 to toggle. So if it is necessary where would that need to be moved? any open IO? Thanks in advance for any shove in a direction to research more
 
link to example: http://ww1.microchip.com/...2S_Interface_Sep11.zip
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    du00000001
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    Re: Using DMA with DCI for I2S driver question 2019/07/19 06:20:24 (permalink)
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    Seems the source files in CE117 are not completely consistent.
    (At least not what was contained in the ...SEP11.zip: I found one reference to RA6, another to port A, Bit 0 - which is certainly not the same pin.)
     
    This pin toggling is to indicate whether the data is for the left or for the right stereo channel.
    (This is the most simple multiplexing scheme of I2S. the other utilizes a pulse on this line to indicate the start of a frame of n channels.)
    It doesn't matter which pin you utilize, but you cannot go without that.

    PEBKAC / EBKAC / POBCAK / PICNIC (eventually see en.wikipedia.org)
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    Thom7724
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    Re: Using DMA with DCI for I2S driver question 2019/07/19 06:47:46 (permalink)
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    Gotcha, thanks for taking the time to explain that. At first glanced I thought it might have been used for hardware interrupt. 
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