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Original question:

AFE7921: Some error about Latte

AFE7921: About AFE7921 config question

zhansheng chen
Prodigy 50 points
Part Number: AFE7921

Hi,

   We had used AFE7921,Our usage needs

Input ref clk = 245.76MHz，input SYSREF

TX channel ：4 ，RX channel ：4 ，We don't use FB channel

JESD 204B lane:4 , runs 9.8304Gbps

RF Channel to serdes mask

ADC1/DAC1 – SRX/TX1
ADC2/DAC2 – SRX/TX2
ADC3/DAC3 – SRX/TX3
ADC4/DAC4 – SRX/TX4

some question about config

1.AFE7921 there are 3 sets of SPI, is SPIA used for config?

2.Regarding the sysParams.modeTdd parameter, we are going to use the FDD mode, what should this parameter be configured to?

3.If I am in TDD mode and the RX/TX 4 channels are used independently, is it configured to 0?

4.About sysParams.topLevelSystemMode I can't find a corresponding description on "AFE79xx_ConfigurationGuide_SBAA417.pdf"

5.What does this mean about sysParams.jesdSystemMode? What do the two parameters before and after the brackets mean? Also we are 4T4R, what should be the parameters?

6. About sysParams.jesdTxLaneMux and sysParams.jesdRxLaneMux,how does the lane to mux ?
Our Correspondence to ADC and serddes is below
ADC1-STX1; DAC1-SRX1
ADC2-STX2; DAC2-SRX2
ADC3-STX3; DAC3-SRX3
ADC4-STX4; DAC4-SRX4

serdes channel 5,6,7,8ia not  connect

7.Regarding sysParams.LMFSHdFb, we don't use the FB channel, can just fill a random parameter in here?

8.If I want to configure other parameters，how to do it？
If we want to config sysrefTermination or serdesTxPreCursor or some other parameters.

  • 0
    TI__Guru 68534 points

    Hello Mr. Chen (@zhansheng chen)

    When you encounter this error

    Please go to devInit.py, and comment out the following lines. You will see the error go away. We are working on debugging this issue at this moment.

    We are looking into your other questions on this E2E post and will get back to you.

    -Kang

  • 0
    TI__Intellectual 2500 points

    Hi Zhansheng,

    1. Yes, SPIA is the main SPI and only SPI available on reset, so would be used for config. SPIB1 and SPIB2 are optional SPI, which can be configured by bringing these onto GPIO if desired.
    2. modeTdd parameter is for GPIO control of TDD, which toggles channels on/off. You can set modeTdd depending on how you want the GPIO to control toggling on/off channels, even if you are using FDD mode. Please see the snippet below from section 2.3 of the config guide for more information on this.
    3. I'm not sure which parameter you are referring to, could you please clarify?
    4. I believe you can leave this parameter unchanged.
    5. JESD System mode refers to the mode for each ADC_JESD instance. The two values are [instance 0, instance 1] RXA/B belong to instance 0, and RXC/D belong to instance 1.  I believe you can use system mode = 2 for your case since you are not using FB, but please see the snippet below from the config guide of table 11 and see section 3.2.2 in the config guide for more information on this.
    6. You can use: 
      1. sysParams.jesdTxLaneMux = [0,1,4,5,2,3,6,7]
      2. sysParams.jesdRxLaneMux = [0,1,4,5,2,3,6,7]
    7. I think you can just leave this parameter unchanged. I don't think you should fill in a completely random value, Latte might give some error if the mode is not valid.
    8. You can use something like sysParams.sysrefTermination or sysParams.serdesTxPreCursor to set these parameters.
      1. You can type dir(sysParams) in the Latte command line to get a list of system parameters you can change by setting sysParams.<parameter>.
      2. This dir(sysParams) command will give an output like below, and you can see if there is a parameter that corresponds to what you would like to change.

    I hope these answers were helpful, please do let me know if you have any follow-up questions.

    Thanks,

    Aman

  • 0 in reply to Aman Thombre
    Prodigy 50 points

    Hi Aman:

              Thanks for asking my question,I had some question about above.

    About question 3,I mean that regarding the sysParams.modeTdd parameter,our 4RX and 4TX are work in TDD mode independently . How to set this parameter.

    About question 6, Why mux  parameter is

    1. sysParams.jesdTxLaneMux = [0,1,4,5,2,3,6,7]
    2. sysParams.jesdRxLaneMux = [0,1,4,5,2,3,6,7]

    how our TX lane mux to ADC and RX lane to DAC

  • 0 in reply to zhansheng chen
    TI__Intellectual 2500 points

    Hi Zhansheng,

    For question 3, the 4RX and 4TX mode will be treated independently however you set this parameter. This parameter will control whether RXA/B/C/D are treated independently and whether TXA/B/C/D are treated independently. Please see the snippet below from the config guide. In summary,

    • modeTdd = 0 means that RXATDD pin control all RX channels (RXA, RXB, RXC, RXD) and TXATDD pin controls all TX channels.
    • modeTdd = 1 means that
      • RXATDD pin controls RXA/B
      • RXCTDD pin controls RXC/D
      • TXATDD pin controls TXA/B
      • TXCTDD pin controls TXC/D
    • modeTdd = 2 means that
      • RXATDD controls RXA, RXBTDD controls TXB, etc.
      • TXATDD controls TXA, TXBTDD controls TXB, etc.

    Please see the config guide snippet below for more information.

    For question 6 about the mux parameters, please let me know your LFMSHdRx and LMFSHdTx parameters.

    The mux parameters I suggested above should map on the ADC-STx side:

    • RXA data to STx1 (0 in the mux parameter)
    • RXB data to STx2 (1)
    • RXC data to STx3 (2)
    • RXD data to STx4 (3)

    Since you are not using FB or STx5-8, we have no data mapped for STx5-8 (params 4-7 in the mux data). I based the choice for the lane muxes on this, please let me know if my understanding on this is correct. Please also let me know the LMFSHd parameters for RX and TX.

    In the same vein, the DAC-SRx side mapping will have:

    • SRx1 (0) mapped to TXA
    • SRx2 (1) mapped to TXB
    • SRx3 (2) mapped to TXC
    • SRx4 (3) mapped to TXD

    Thanks,

    Aman

  • 0 in reply to Aman Thombre
    Prodigy 50 points

    About question 6,our LMFS is 48410,lane data rate 9.8304Gbps, 1 link mode

    and want to

    • RXA data to STx1
    • RXB data to STx2
    • RXC data to STx3
    • RXD data to STx4
    • SRx1  mapped to TXA
    • SRx2  mapped to TXB
    • SRx3 mapped to TXC
    • SRx4  mapped to TXD
  • +1 in reply to zhansheng chen
    TI__Intellectual 2500 points

    Hi Zhansheng,

    Thanks for clarifying the LMFS - I was somehow under the impression that LMFS was 22210, my apologies.

    Please use both lane jesdTxLaneMux and jesdRxLaneMux = [0,1,2,3,4,5,6,7] for this case. Also, please set jesdSystemMode = 3 (from question 5, use the '1R' mode). These params should give the results you are looking for. Apologies again for the confusion. 

    Thanks,

    Aman