Can I run TDM16 at 96kHz?

PhilipJ Question

Mar 7, 2017 00:00

I have done a few designs using ADAU1446 and ADAU1442 in which we run the chip from a 24.576 MHz crystal so I have done TDM8 interfaces at 96kHz without problems.

Now I see from the data sheet that ADAU1450/51/52 claims "48 channel, 32-bit digital I/O up to 192 kHz" but only has 4 SDATA input pins and 4 output pins, but SDATA0 and 1 can run TDM16

My question is, can theses interfaces run TDM16 at 96kHz or even 192 kHz and if so what frequency master clock do we have to provide and how do we provide it? Is it the chips own master clock or do we supply an external clock?

thanks

PhilipJ

Audio Signal Processors

adau1446

adau1442

SigmaDSP Audio Processors

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DaveThib Reply

Apr 11, 2017 00:00

Hello PhillipJ,

You will only be able to run TDM16 at 48kHz fs or slower. The max for TDM8 is 96kHz. The max for TDM4 is 192kHz.

So that means that at 48kHz you can get 48 channels in and out of the DSP. At 96kHz you will only get 32 channels and at 192kHz you will get 16 channels in and out.

What is your product development schedule? So tell me what you would like to do? How many inputs and outputs and at what sample rate do you wish to run the core?

Dave T

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PhilipJ Reply

Apr 12, 2017 00:00

Hi,

thanks for the reply. I thought this would be the case as I tried it on the chip I had (ADAU1442) I just wondered if the ADAU1452 had added something clever to get over the need for a 50+ MHz clock.

PhilipJ

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DaveThib Reply

Apr 12, 2017 00:00

Hello PhilipJ,

What is your product development schedule? When do you need prototypes?

Dave T

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PhilipJ Reply

Apr 13, 2017 00:00

Hi Dave,

There isn't a product development schedule as such, it is one of those things were a client has approached us and asked if a certain thing would be possible.

Basically we design a lot of Dante audio network equipment, Dante can be 32 channels of audio at 96kHz (4 x TDM8 streams) or 64 channels at 48 kHz (8 x TDM8 or 4 x TDM16). I was trying to think of a way to get one or other presented to a SigmaDSP chip, not to process all 64 channels but to be able to select a number of channels from the total. The system can change sample rate during operation through the Dante network control software.

Having just read that as I wrote it, I guess I could use TDM16 at 48 kHz which works, and drop to TDM8 for the 96kHz (I am thinking of the ADAU1452 device). That gets me up to 48 channels in.

Thanks Dave, sometimes describing what you are trying to do to another engineer helps clarify the thought process.

I do really like the sigmaDSP devices, for somebody who is not too hot on the deep maths of DSP processing they are a really great way to get products quickly. I shall be looking forward to any new ADAU devices that are planned for the future...

regards

PhilipJ

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