AnsweredAssumed Answered

ADAU1452 - "clickless" ASRC, Multiplexers + Crossovers

Question asked by BabyNSX on Jun 8, 2015
Latest reply on Jan 25, 2016 by logoho

I've been working with SigmaDSPs for over 10 years now and have developed several products using them. I'm currently embarking on a design using an ADAU1452 for the first time and am running into a problem with both the ASRC, Multiplexer blocks and Crossover filters.


I've been using SigmaStudio versions 3.11 and 3.12 beta for all these tests with the same results. I've also been using both Analog Devices development board as well as my own hardware for diving into this problem. At present the problem "seems" to be limited to my hardware; however, I have seen the problems on the development board as well. Here is a summary of my issues:


1.     Crossover filters: It seems that whenever I try to add one of these filter blocks to my project the compiler crashes. I've had to eliminate these filter types from my projects to proceed. Is there a known bug with these filter types or is there perhaps something wrong on my end?


2.     My project is configured with 1 ADC connected to port 0 (1452 is I2S master). This input is tied directly to the DSP core. I have 3 other inputs, which are all their own I2S masters. These inputs go through the ASRC - as shown here:

SigmaDSP project input capture.png


When the project first runs and before any valid input data is present on the ASRC inputs and I adjust the volume settings I can hear clicks during each of the write instructions. This is true for both my MCU based code writing these instructions or within SigmaStudio if I simply slide the volume sliders up and down.


Once a valid I2S stream (Or SPDIF) has been placed on the respective input, then changing the volume has no clicks or pops. It seems that there is an initialization issue with the ASRC that once complete the system behaves normally. Oddly, this seems to be only the case with my own hardware and I do not see the same problem with the development board. I can't seem to figure out why this would be; although I have seen some issues with the volume slider once or twice with the evaluation board, it does seem to be more forgiving with this.


3. In addition to the ASRC issue, there seems to be a problem with the input multiplexer. I can't seem to get this to operate with click less behavior. Again this seems to be more true with my hardware, although I have seen cases with the development board where this was also true. There seems to be some inconsistencies with both this and the ASRC.


Sorry, if some of this seems vague, I've tried many things to try and pinpoint the source of the problem; however, these efforts have not yielded anything.


It may be worth noting that I'm using I2C communication between the ADAU1452 and host MCU, while the development board uses SPI.


Your thoughts and help with this would be greatly appreciated.