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LMH1208: LMH1208， Register Configuration

shuoyang gao
Prodigy 20 points
Part Number: LMH1208
Thank you for listening.I have obtained the LMH1208 programming guide, but I still need some program assistance. Can you provide a reference code to configure the chip, such as using In to receive data and then SDI_ I only need a reference program for outputting raw data in OUT1. I sincerely hope you can provide it, which is very important to me. Thank you very much.
  • 0
    TI__Expert 6730 points

    Hi Shuoyang,

    Hope you are doing well. Is my understanding correct that you want to input data into IN0+- and have a raw data output at OUT1?

    Like in this diagram? 

    If so here is a sequence you can use to enable raw data from SDI_OUT1 and SDI_OUT2 for the LMH1208.

    Command Register Value Mask  //Comments
    RAW FF 04 07 //Select CTLE Register Page
    RAW 01 02 02

    //Read back LOS indicator for IN0

    (1: LOS, 0: Signal Detected)
    RAW 09 20 20 //Enable Independent Output Control Override
    RAW 1C 08 0C //Set OUT_CTRL functionality to default settings
    RAW 1C 00 C0 //Output raw data (EQ only) on SDI_OUT1/SDI_OUT2

    If my understanding is incorrect, please let me know and I will do my best to help.

    Best,

    Nick E.

  • 0 in reply to Nick Peabody
    Prodigy 20 points

    Thank you very much for your reply. It has been very helpful to me and your understanding is also very accurate. I just have one more thing unclear, I just need to care about sdi_out1 don't need any other output ports for the raw data . My data rate is 3G.

    Moreover, there are several detailed requirements and configurations that I need to ask you:

    1.Do I need to reset these three page registers? If necessary, should I reset it at the beginning?

    2.How should I configure the signal detection function of IN0 if I need to turn it on?

    3. How can I configure SDI_OUT1 Slow Rate Control Overrides:

    4. Do I need to configure Interrupt Outputs Programmed by Interrupt Registers? If so, what should I do?

    How should I configure these. The above are actually the points that I need to think about. I am not sure if I should configure them, and I hope you can provide me with help.

    Sincerely thank you.

  • 0 in reply to shuoyang gao
    TI__Expert 6730 points

    Hi Shuoyang,

    No problem. Here are my answers to your questions:

    shuoyang gao said:
    1.Do I need to reset these three page registers? If necessary, should I reset it at the beginning?
    • The page registers allow access to a different subset of registers underneath 0xFF. It isn't necessary to reset these registers, but to access another set of registers it's required to write again to 0xFF. For example, you could write 0x04 to 0xFF to access the CTLE Register page and then send 0x05 to 0xFF and access the Driver register page right after. 
    shuoyang gao said:
    2.How should I configure the signal detection function of IN0 if I need to turn it on?
    • To configure the signal detect function on IN0 please refer to this table:
    • The commands to register 0x56 enable the interrupt for the SD_N pin if the IN0 signal is detected. 
    • You can then read the status of the interrupt from register 0x54 above and from the SD_N pin.
    • You can also read the status of IN0 from register 0x01 in the CTLE register page.
    shuoyang gao said:
    3. How can I configure SDI_OUT1 Slow Rate Control Overrides:
    • Please refer to the screenshot from the programming guide. Navigate to the Driver register page then enable slew rate control and then choose the slew rate for your application. 1 = SDI_OUT1 Slew Rate is controlled by Reg 0x60[4:3]. I highlighted 3G for your application.
    shuoyang gao said:
    4. Do I need to configure Interrupt Outputs Programmed by Interrupt Registers? If so, what should I do?
    • Please refer to my answer to your second question and let me know if that answers this question.

    Best wishes,

    Nick E.