adau1452miniz board, AD1938 codecs 192khz possibility question

Skfir Question

Jun 17, 2014 00:00

Hi guyz!

Many thanks to AD people, now I have 1452miniz board and can continue development of the assistive device for the blind. Now I am reading the board's datasheet and meet the following passage: "The AD1938 is configured to run at a sample rate of 44.1 kHz or 48 kHz. It is not possible to change this setting. Even though the ADAU1452 is very flexible and can run at any sample rate up to 192 kHz, the analog audio inputs and outputs on the EVAL-ADAU1452MINIZ may be distorted or silent if a sample rate other than 44.1 kHz or 48 kHz is used for the ADAU1452 serial ports."

So I just wanted to be sure that I know what will happen if I try to make a project for 192khz. Will nothing work?

Do I have to tweak the board? Or, the processor ticks the clock pins on the AD1938 with fixed 48Khz frequency regardless of the mode, in which AD1938 samples the incoming signal? Which means everything will work fine? Could anybody please help and clarify? I am really confused.

Thank you guyz!

Audio Signal Processors

adau1452

ad1938

Integrated/Special Purpose A/D Converters

SigmaDSP Audio Processors

Audio CODECs

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KJBob Reply

Jun 17, 2014 00:00

Hi Skfir,

I'm afraid that in the 1452 eval board, the codec is hardwired in a standalone mode at 44-48KHz sample rate. It is possible, although rather difficult, to modify the board to get around this. Please see this discussion:

Is it impossible to set Fs=192kHz for EVAL-ADAU1452MINIZ?

Best regards,

Bob

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drugoimir Reply

Jun 19, 2014 00:00

Hi,

on the 1442 evaluation board i had to tweak both the usbi interface and the evboard in order to use the spi

for ad1938 programming.

I hardly remember, but i had to wire the spi interface of the 1938 to the usbi, taking also an extra line (the chip

select if memory assists me) out of it.

Then i was able to add this chip to the connected devices, specifying an spi interface, and control it.

Don't know if the same can be done on the 1452 evaluation board, but i see no reason for the contrary: the 1452 can drive the 1938, but as far i know, it cannot program it, so the 1938 might have the spi interface pins free.

Bye

Tom

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Skfir Reply

Jun 19, 2014 00:00

Yup, I understand, thank you guyz!!

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francescodenetto Reply

Dec 25, 2015 00:00

Have you a schematic? I have a adau1452 evaluation board...And i'dd like to improve sampling rate of ad1938 to get best audio quality

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