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ASRC work abnormally with noise generated

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Thread Summary

The user experienced noise issues when using ASRC on ADSP21564, which were not present on ADSP21565. The problem was resolved by changing the clock edge configuration of the PCG unit to match that of the ASRC, switching from rising edge to falling edge. The issue was likely due to a clock synchronization or initialization timing problem.
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Category: Software
Product Number: ADSP21564
Software Version: CCES 3.0.2 & SigmaStudio+ 2.3.0

We are now trying to use ADSP21564 on the target AMP product developments. The IDE platforms we used are CCES 3.0.2 and SigmaStudio+ 2.3.0. We have tested related designs on ADSP21565 with the same IDE platforms. And the test results showed that all jobs done ok on ADSP21565, without any noises generated when using ASRC. But it is very strange that noises generated after we switched it from ADSP21565 to ADSP21564. We have checked the inputs and outputs configurations of its ASRC, and confirmed that all are OK. So, we concluded that the noise are generated by the ASRC units of ADSP21564. The hardware connections are as below:

Detailed configurations and connections are as pictures below:

Moreover, we tested the inputs of A2B with ASRC unconnected and  its outputs are with no noises; we also tested the tone generator driven by the PCG directly and it is also with no noises.

Could you help me to confirm what the problems are? Is it possible that ASRCs on ADSP21564 are not configured correctly or it is an ASRC hardware issue? 

Thank you!

Edit Notes

fixed a typo.
[edited by: AlpineHumorhxu at 5:38 AM (GMT -4) on 30 Jun 2025]
Parents
  • Hi,

    Can you please test the ASRC example available in the ADSP-21568 BSP to isolate the issue you are experiencing on the ADSP-21564. Running this example on your ADSP-21564 platform will help verify whether the ASRC hardware and its basic configuration are working as expected.

    Please download and install the ADSP-21568 Board support package (BSP) from the link given below.
    download.analog.com/.../ADI_EV-2156x_EZ-KIT-Rel3.0.0.exe

    Once installed, please find the ASRC example available in the below mentioned installation path.
    [Installation directory]:\Analog Devices\EV-2156x_EZ-KIT-Rel3.0.0\EV-2156x_EZ-KIT\Examples\drivers\asrc

    Also, could you please check if there are any hardware differences between your ADSP-21565 and ADSP-21564 setups (e.g. power supply, clock sources, PCB layout, or connectors).

    Regards,
    Nandini C

  • Thanks for your reply! We modified the clock edge configuration as that of the demo app of ADSP21568, and the problem was solved. As the clock configuration below, we just changed it from rising edge to falling edge, then the problem was solved.

    Thank you!

  • Hi,

    Glad to know that the issue got resolved and thanks for the update.

    Please let us know if you need further assistance on this.

    Regards,
    Nandini C

  • It seems still not very stable. Sometimes, it started OK; and sometimes it started with noises, and then it changed to be OK after 1~2 minutes. 

Reply Children
  • Hi,

    Thanks for the update.

    Since the issue is intermittent and it resolves after a 1~2 minutes, we believe it is related to clock synchronization or initialization timing issue rather than a ASRC hardware problem.

    1) Please ensure that the ASRC is initialized only after all input clocks (MCLK, LRCLK, BCLK) are stable. You can insert a delay or check PLL lock status before enabling ASRC.
    2) Have you had a chance to run the BSP example we shared earlier? Does it operate consistently without any issue?
    3) As the issue is intermittent, could you please share how frequently the noise occurs?

    Regards,
    Nandini C

  • Thanks for your answer! It is caused by the misconfiguration of our PCG unit. After changing the edge to be consistent with that of ASRC, the noise disappeared. 

    Thanks for your great supports!