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ADAU1452 External Delay issue

Question asked by Toino on Dec 3, 2014
Latest reply on Dec 8, 2014 by Toino

Dear support team,


I am trying to use the 23K245 SRAM with the ADAU1452 in self-booting mode and need your help in order to solve some issues.



The first issue is related to the SS_M0 (pin26). Apparently the External Delay always configures MP0 to this function and that conflicts with the E2PROM CS .

The solution that I have found is fully parallel the SRAM and the E2PROM and control their HOLD pins with MP5. As the E2PROM is only needed for booting, I put their HOLD pin at zero via MP5 and a inverter in order to force their SO-pin into tri-state.

So far, it works, whoever it is brute-force solution.

Maybe another solution is to mutually disable the CS pins with OR-gates and MP5. Have not tried it.


My first question is if they are a way to use MP5 to CS the SRAM directly in order to keep it independent of E2Prom?

Have tried the Master Control Port i/o but I don't know the parameters.




The second issue is related with the External Delay strange behavior:


A) Programing for ex. 24000 Max Delay, the Distortion measured at output is the same as the straight connection between input and output (about 0.001%)

However with  24002 Max Delay value, the THD goes to 95%. Depending on Max Delay values, they are no distortion or the distortion heavily increases. 


B) With, for example, 24000 max delay, changing the delay parameter has no effect at all; it acts as if the delay is fixed.


So, my second question is: The External Delay algorithm is working properly or needs some kind of special parameter?



3) Finally I have a request. Please do one External Delay with Voltage-control as the Multi-Tap Voltage Controlled Delay.



Thank you