AFE7901: Change Nyquist band (and RX frequency) after device bringup sequence

Hi Alon,

On the ADC side it is possible to change the the NCO across Nyquist zones but on the DAC side this is not supported. 

Just to confirm are you using the CAFE library 'updateRxNco' function to change the NCO? 

Can you explain more when you say the 'operation fails'? Do you see no input or does the spectrum look bad? 

Regards,

David Chaparro 

I'm using the `updateRxNco` function and it returns a status failed return value.

After inspecting the function it looks like it fails when asserting that both frequencies (current and new one) are on the same nyquist band (which they are not).

Thanks!

Hi, just checking in to see if there are any updates or results you could share regarding this issue.

thank you in advance!

Hi Alon,

Can you share the AFE script that you are using for the AFE configuration? There should be no issues changing NCO frequencies. Can you also share the function call that is failing? 

Regards,

David Chaparro

Hi, perhaps I was not clear but the configuration script successfully configures the AFE (sharing it just in case - AFE Configuration).
The problem arise by trying to call `updateRxNco` function after the configuration stage.

After inspecting the `updateRxNco` source in the CAFE library I noticed that it verifies  and aborts early in case of different nyquist bands between the old frequency and the new one:

    uint32_t mixerVal = 3000;
    uint32_t Fadc = AFE79_CURR_SYSPARAM.FadcRx;
    uint64_t ncoFreq;
    uint8_t byteList[7];
    uint8_t numOfOperands = 0;
    uint8_t byteListRxNCO[4];
    uint8_t newNyquistNo;
    uint8_t bringupNyquistNo = ((AFE79_CURR_SYSPARAM.rxNco[0][chNo][0] * 2) / Fadc);

    if (AFE79_CURR_SYSPARAM.ncoFreqMode == 1) /*FCW mode*/
    {
        ncoFreq = ((uint64_t)mixer * (uint64_t)Fadc) / (0x100000000);
        ncoFreq += Fadc * (bringupNyquistNo >> 1);
        newNyquistNo = (mixer >> 31);
        if (newNyquistNo != (bringupNyquistNo & 1)){ // Checking if the nyquist frequency
            afeLogErr("%s", "The new Nyquist frequency and the frequency set in bringup should be same");
            AFE79_PARAMS_VALID(newNyquistNo == (bringupNyquistNo & 1));
        }
    }
    else
    {
        ncoFreq = mixer;
        mixer = mixer % Fadc;
        newNyquistNo = ((ncoFreq * 2) / Fadc);
        if (newNyquistNo != bringupNyquistNo){ // Checking if the nyquist frequency
            afeLogErr("%s", "The new Nyquist frequency and the frequency set in bringup should be same");
            AFE79_PARAMS_VALID(newNyquistNo == bringupNyquistNo);
        }
    }

We are using the latest CAFE version (V2p6)

Thanks!

Hi, just checking in - any new updates on this?
I'm still unsure if this isn't supported by design or its a misconfiguration / I'm not using the right functions.

Thanks!