ADAU1452 evaluation board AUX ADC external control

Hi,

I would like to achieve a similar result, being able to select a source (SPDFI, I²S, analog 1 and 2...) with a help of a button or whatever.

Some suggestions ?

Thanks a lot,

Fabian

Hello Mark & Fabian,

An Index Selectable Mux selects its input according to the number at its red pin. An input of zero selects the first input (or stereo pair). An input of one selects the next, etc. Thus, the selection can be made by a device external to the ADAU1452 -- such as pushbutton(s), an encoder, or a potentiometer. The example shown below uses the R1 potentiometer built into the newer Rev B eval boards.

The tone oscillators merely represent the inputs. The ADAU1452's Aux ADC outputs a decimal (8.24 format) number from 0.0 to 0.999 -- its highest output is equal to 1023 / 1024, thus it never makes it completely to 1.0. If we multiply this by the integer (32.0) number 5, the result is an integer varying from zero to four depending upon the pot setting (the multiplication always rounds down). This number controls the Mux.

Best regards,

Bob

Hi Bob,

thanks a lot for these informations, I will study them and try to apply them. It seems to be particularly intersesting for me.

Have a nice day,

Fabian

Many thanks for that example, Bob. That's very helpful! Kind regards, Mark.

Hi Bob, I tried your example but it didn't worked, so I took the example for the volume control and added 2 readback blocs and one Arimetic shift bloc in between and it works. Is it right like this ?
Thanks a lot,

Fabian

Hi Bob, I tried your example but it didn't worked, so I took the example for the volume control and added 2 readback blocs and one Arimetic shift bloc in between and it works. Is it right like this ?
Thanks a lot,

Fabian

(Sorry, I replied to myself, I discover the functionalities... :-) )

Hi Thom,

I tried the example of Bob but added some blocs because it didn't worked like this. Have a look at the subject and you will see my configuration.

Best regards, Fabian

Hello Mark and Fabian,

Sorry I goofed on this one. The ADAU1452's Aux ADC outputs are 0 -- 1024 integer rather than 0 - 0.999 decimal -- the latter is for the ADAU1701. This is why my 'solution' didn't work. Troubleshooting with Readback blocks is the way to fix this.

Best regards,

Bob

Hi Bob,
there is absolutely no problem, it brought me to think by myself and understand a little bit more how this software works, even if there are many parameters that are unknown to me.
Thanks to your first answer, I could after 2 years, achieve the perfect configuration for me :

- one analog input without volume control, I have an old Luxman C300 preamp with my vinyl turntable

- the second analong input without volume control, I have the analog outputs of my home theater amplifier.

- on the spdif input with volume control on the board is linked to the digital output (fixed) of my home theater amplifier that I just use as a digital switch.

I can now select my inputs, control the volume only for the digital input and then apply a filtration for my loudspeakers.

Basicly I wanted to implement the board in a digital preamp (3D LAB PR6) but I am considering now to fix the board in a appropriate case. I have now to find out how to select the inputs with the push button.

It is very difficult to mary home theater and quality hifi, with a good dac on the spdif output, should sound even better !

Thanks again and best regards in NY, my brother is living there !

Fabian

That's awesome, Fabian! Nice project! :)