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#1 2011-Jun-08 02:09:09

carlos82
Member
Registered: 2011-Mar-03
Posts: 12

NOMAC without DMA controller and Ethernet port.

Hi everyone,

I have two Virtex5 connected point to point (at the base-band I/Q samples level, of course, without radio boards) to do some exercises with your OFDM Tx/Rx model.

I have generated a peripheral from the version 16.1 of the OFDM reference model and have integrated into a new project. This project includes only the ofdm_txrx_supermimo and the radio bridge,which I use to route the base-band I/Q samples to my FPGA input/output pins.

My embedded system does not integrate DMA controller or Ethernet port. Thus, we want to generate the packet payloads by the PPC, which writes data payload directly in the BRAM packet buffer.

Using WARP drivers I've tried to debug the NOMAC.c file. To build the project I had to disable the initialization of Radio Controller of warpphy_init as well as all the configuration of DMA warpmac_init.

To load the payload on BRAM packet buffer I used the memcpy instead of XDmaCentral_Transfer as follows:

I modified the main of NOMAC like this:

    while (1)
    {
        dataFromNetworkLayer_callback (20, "12345678900123456789");
        usleep (1000000);
    }


and I've also changed dataFromNetworkLayer_callback function :

    Macframe txFrame;

    txFrame.header.length = length;
   
    txFrame.header.fullRate = HDR_FULLRATE_QPSK;;

    txFrame.header.codeRate = HDR_CODE_RATE_34;

    warpmac_prepPhyForXmit (& txFrame, pktBufInd_tx)

    if (length! = 0)
    {
        memcpy ((void *) warpphy_getBuffAddr (pktBufInd_tx) + NUM_HEADER_BYTES, payload, length);
    }

    warpmac_startPhyXmit (pktBufInd_tx)

    warpmac_finishPhyXmit ();


When I run on hardware warpmac_finishPhyXmit never returns, that is never ending transmission of the packet.
Does anyone know why it happens?

Thanks,

Last edited by carlos82 (2011-Jun-08 12:23:31)

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#2 2011-Jun-08 21:19:48

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5159

Re: NOMAC without DMA controller and Ethernet port.

Is the PHY initialization still being run (usually in warpphy_init() and warpmac_init())? One explanation for the Tx never finishing is if the modulation rates aren't initialized to sane values. If they're zero, for example, the PHY can run forever, "transmitting" zero bits per symbol.

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