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Question about a slot of AD1977

Question asked by IRON on Nov 17, 2015
Latest reply on Nov 19, 2015 by DaveThib

Hello all


I have some questions about ADAU1977’s slot width(datasheet p.27/68).


Is this slot width programmable to change?

In the data sheet, I can see there are three types of slot widths which are 16/24/32BITS.

But, I do not see any registers to programmably change the part.


I am using ADAU1977(as a slave ADC), ADSP21489(as a master DSP), and AD1934(as a slave DAC) in my system.


On page 28/68 of ADAU1977 data sheet, there is a line saying

“In slave mode, this limitation does not exist because the bit clock and frame clock are fed to the ADAU1977.”


I am guessing this line is saying something important for me to understand this point.


But, I have 3 unclear matters below.


->I am not still clear if I can put a certain certain number(16/24/32bits) of bits in a slot programmably in TDM mode on SHARC.


->I am also wondering if a number of bits(16/24/32bits) in a slot on the ADC and DAC is depending on the setting on SHARC side or not.


->I am also confused with the difference between the size of the slot and the word length.


Could you please explain these things for me?


Thank you always.