I2S to COB format converter? (PCM54P dac)

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Hello,

I want to try PCM54 with XMOS USB transport, but it supports only parallel input data. Tried search, nowhere found an schematic what I should do to take out parallel data from i2s... And how does it work the protocol, in i2s there is LE signal, that enables the output, but there is only data bits. Is there some code or string on MSB or LSB pin, that enables the output, or something else? I can make a matrix with counters, D-triggers and AND logic to make parallel data for the DAC, but don't know how does it will work...

Regards,

Milen
 
Found these sbhematicsa on-line.
How about using the Ladder DAC schematic without the Resistors, that's parallel Data isn't it? (Albeit 18 bits and Mono I think, could be modified for 16 bits if that's what the PCM54 is.)

And then the other circuit could be the drive to get two channels from one i2S source.

Just a thought?
 

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For 2’s complement to COB, you need to invert all the bits except the MSB, I believe. If you have the serial data, feed it into a serial to parallel shift register(s) and then invert the necessary bits with inverters and feed the DAC at the right time. The kits above are 2’s complement, but could be stage 1.
 
For 2’s complement to COB, you need to invert all the bits except the MSB, I believe. If you have the serial data, feed it into a serial to parallel shift register(s) and then invert the necessary bits with inverters and feed the DAC at the right time. The kits above are 2’s complement, but could be stage 1.

Inverting just the MSB would also work I think.

P.
 
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