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example for Cppi/Qmss

Jean-luc
Prodigy 30 points


Hello,

I have few question about the CPPI/QMSS configuration.

I need to use the SRIO/message passing  in my project and I'm using to learn and configure the cppi these files: test_host_mode.c and test_mono_mode.c

Those two files seem to be good example to learn how to use and configure Cppi/Qmss and the rxflow for message passing, with my EVM6678 board, I can run and test those examples without too much problem. But I have few questions:

- I still don't understand how the transmit queue txQueHnd  and  txdata  is linked or loopback to rxQueHnd. These examples set the  Rxflow with Cppi_configureRxFlow and I don't see any link  with the txQueHnd or txCmplQueHnd. I missed something here, and I need some inputs from someone here !

I checked other examples and the loopback seem to be created  with this API  Qmss_queueDivert (txQueHnd, rxQueHnd, Qmss_Location_TAIL) and without setting the rxflow at all.

I'm not using interrupt in ACC at point, this code just poll Qmss_getQueueEntryCount for rxQueHnd.

 

Thanks

 

  • 0
    TI__Mastermind 23525 points

    Jean-luc,

    Are you referring to the Mulitcore Navigator User's Guide?  http://focus.ti.com/lit/ug/sprugr9c/sprugr9c.pdf  In section 2.3.3, it mentions that "In many cases, the receive queue
    is, in fact, also a transmit queue for another peer entity."  With the loopback PKTDMA, if you look at section 2.5.2 the RX flow is specified in the TX descriptor, so the TX is essentially hard wired to the RX.   So once to push a data into tx queue, the data will be visible in the rx channel which will use the flow to transfer data to a specific location. Hope this helps.

     

    Regards,

    Travis

  • 0 in reply to tscheck
    Expert 1010 points

    tscheck,

    im currently referring to cppiExampleProject as well as cppiTestProject avaible under pdk of MCSDK 2.0. Im a bit confused as to which code is need to take as an reference since im into designing the overall communication framework architecture for my module using Multicore navigator.

    Would you suggest me to use these available projects as reference, or is there something else which i can look at ?

    I require an appropriate sample program to test the communication between cores as well as communication between the Core and the Hardware accelerators like BCP, FFTC etc using PKTDMAs using Qmss and Cppi of the Multicore navigator.

     

    Regards

    Santosh

  • 0 in reply to Santosh Pinto
    TI__Mastermind 23525 points

    Santosh,

    The example project is better for a reference design, you can reuse most of that code in your application.  While the test projects provide more of a unit test for the LLD and may give you a flavor for additional LLD features that the example doesn't use.  In the C6670 PDK there are examples projects for all the components you mention.  These are the only projects available.

     

    Regards,

    Travis