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TDM Channel Configuration

Category: Software
Product Number: AD2428
Software Version: SS+ 2.1


I have a question regarding the TDM interface of the AD2428. I would like to transmit 8 channels of TDM from peripheral ADCs on a subnode plus 4 channels of TDm from PDM mics, also connected to the subnode. The mainnode recieves these signals and outputs them with TDM16 to a ADAU1467 DSP. Transmission works but even though I set up the peripheral ADCs to occupy tdm slots 0-7, the signals end up in all kinds of slots in SS+. Is there a way to configure the a²b transmission in a way that the slots are occupied AT LEAST consistently?



  • Hi  ,

    Initially you can configure the Stream Configuration Data, then do pin assignments for the Subnode0 and Main node. Then configure the PDM and TDM data at subnode0 and then main node. 

    If you don't enable the Manual Slot Configuration, then the System automatically selects the upstream/downstream on each node. You can do it first and check if the slot assignments are still corrupted or not.

  • HI Sebastian,

    Could you point me in the right direction, where can I configure the PDM and TDM data?

    You can follow the way that i mentioned in my previous conversation to configure Sigma Studio/ Sigma Studio+. The Stream Configuration tab need to be defined first to understand the slot information and direction of slot information.

    If you don't enable the Manual Slot Configuration, then the System automatically selects the upstream/downstream on each node. That means the number of slots in upstream and downstream for each nodes have already been configured in the Stream Configuration. 

  • Where can I find this Stream Configuration Tab? What I do find is a "Stream View" Tab, but there is nothing I can change or configure.

  • On the Right Hand side of the SS+ GUI there is a Project Pane. Click on it and Expand the Networks->A2Bnetwork->A2B_0. 
    there you can find it. 

Reply Children
  • I found it. Thanks! Now what do I do? I can define Streams but how do i define the exact sources like pdm inputs or tdm slots received at the subnode via rx?


    Can I refer one sample document in the SS+ project files ? You can navigate to the below project:

    C:\Analog Devices\ADI_A2B-SSPlus_Software-Rel1.3.0\Schematics\PC\adi_a2b_AD2428WD1BZ.ssprj

    The PDM configuration on subnode and the stream assignments have already there on this project. You can use this project to start with.

  • Is it possible to tell me how I can configure the slot assignment for PDM mics and peripheral ADCs with consecutive TDM-Slots transmitted to the altRX of the SubNode, without making me look for this in an example project? Can you please just tell me how to do it? I am currently searching for anything close to what i want in the example project, but this is really not helpful.

  • Hi Sebastian,

    Please find the manual:[]=sigmastudio&s[]=slot&s[]=assignment
    this has the information about how the slots are getting configured

  • Hi,
    I read this and again there is no information about the position of the TDM slots in the stream. All this is saying is how many slots are going to which node, but nothing about which TDM slot contains which signal.
    I want the signal of the microphones on RX0 to be in TDM slots 0-1 and the signal of the microphones on RX1 in TDM slots 2-3 for example. And i want it to be consistent between downloads and startups. Can you tell me how to achieve this?

  • I can define the streams in the stream configuration and assign them. The problem is I don't see any way of assigning the streams to data recieved at DRX0/DRX1 or ALTRX(DTX1(IO4).

  • Look, the example project you refered to does not help, because I don't know what to look for. The wiki page you refered to does not help, because it does not say anything about how to link a signal on a pin to a stream. I cannot resolve the missing link betweet the data on the TX1 pin (TDM8) and the corresponding stream, that i defined. Same goes for the PDM signals on RX0 and RX1. I read the documentation, read the wiki, the help pages and asked here. And I have to say, all three of these resources don't seem to be particularly helpful.

  • Hi Sebastian,

    Since this is the same issue you´ve reached out to me about via email, let´s continue to discussion that way. We can post the outcome here. This way, there won´t be multiple engineers working on the same technical request. Thanks for your understanding!

    I´ll reach out to you with a response before the end of the day.

    Best regards,


  • Hi Maikel,
    thanks! Do you mean I have to add a Non Programmable Generic device for each PDM microphone? I did that and for now it seems to be working as expected. However, I don't quite understand why. How does the AD2428 know, that the four generic devices represent PDM mics and the other two ADCs? I mean, I connect all of them to the RX "Pin" in SS+, but that isn't really a pin is it? I would think that the slots in the stream configuration should be linked somehow to the pins on the AD2428.

  • This request is being handled via private email.