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Use 1772 to convert analog to I2S?

Question asked by wingated Employee on Jan 17, 2013
Latest reply on Jan 18, 2013 by BillJ

Hi all,    


I'm trying to do something very simple: I need to convert 4 analog signals to an I2S signal.  I had hoped to use the 1772 to accomplish both the ADC and the generation of the I2S signals; from the data sheet, it seems like this should be possible.  (Ideally, I would have two I2S signals, each with a stereo pair of signals, for a total of 4).


I've gone through both the 1772 and the eval platform's documentation, and tried to set up some sort of serial output -- but I just can't seem to get anything to show up on the serial output pins! (that is, I've got a scope connected up to the serial output lines, and there's never any activity on them at all)


The basic audio pass-through example in the documentation worked fine, so the board appears to be ok.


I'm using the latest version of SigmaDSP.


A bit more detail:


* I have a 48MHz clock hooked up to the LRCLK line.

* I have a 48*64Mhz clock hooked up to the BCLK line.

* I have nothing connected to the MCLK line (I'd rather not use an external MCLK if I can avoid it, but I can if I absolutely must).

* I have my scope connected to the SDATA0/1 lines.

* The eval board came with jumpers on S5 and S6 (on the J9 block). I've tried with them on and with them off.  Neither seems to work.

* I've set the signal routing stuff as specified in the documentation, including enabling the "Output ASRC" button.


I've attached my sigmadsp project, in case it's helpful.


Any help would be appreciated.  Thanks!