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TMS320F28386D: Why there are multiple models in IBIS?

user4681972
Prodigy 90 points
Part Number: TMS320F28386D
Other Parts Discussed in Thread: DAC7811

Why there are several different models in MCU IBIS model? I can see they have different parameters.

Can I setup it in software, not for simulation, I mean for production?

For example, the default model is BCF3385DSHYPBFZ_7LM, but the simulation doesn't work. Then, I change the model to BCF3350CSHYPBFZ_7LM and the result looks good. So, how to setup it in software?

Thanks

  • 0
    TI__Mastermind 38830 points

    Could you provide more details on what you mean by simulation doesn't work if  buffer BCF3385DSHYPBFZ_7LM is used for GPIO18?  Did it give an error at simulation or the IV curve doesn't look correct or something else?

    Thanks,

    Joseph

  • 0 in reply to Joseph Casuga
    Prodigy 90 points

    GPIO18 is SPI clock signal on my board, I want to check the monotonic edge as the signal crosses through the logic-level threshold zone. But if I use BCF3385DSHYPBFZ_7LM, the edge crosses thresholds several time. I change to BCF3350CSHYPBFZ_7LM and it becomes monotonic.

  • 0 in reply to user4681972
    TI__Mastermind 38830 points

    Hi,

    Checking with our design IO team for feedback on your findings.  It might take several days to get a response back from us.

    Best regards,

    Joseph

  • 0 in reply to user4681972
    TI__Expert 5710 points

    You will not be able to change from BCF3385 to BCF3350 on GPIO18.  For that you would need to use one of the other GPIO that uses the BCF3350 buffer.

    Can you provide more information on the setup.  What else is connected to the bus?  Is it a driver or reciever?  Waveform pictures?  You should have the 'BCF3385D_DRIVER_MODE_3P3' model selected if it is a driver (not either of the 'WEAK_PULL..' options).


    Best regards,

    Jason
     

  • 0 in reply to Jason Whiles
    Prodigy 90 points

    Hi, I don't think I can use another GPIO. It's SPI clock signal between MCU, FPGA and twelve MDACs (DAC7811). I use FPGA to setup gain to MDACs and MCU read back. MCU is the driver when read back.

    It's 'BCF3385D_DRIVER_MODE_3P3' model when MCU is driver. The waveform shows one of the MDAC clk signal with MCU as a driver. The signal crosses threshold several times. I have added a series resistor.

    Thanks

  • 0 in reply to user4681972
    TI__Expert 5710 points

    Thanks for the additional information.  That is a lot of distributed loads, I guess you are getting some reflections.  Glad the resistor solved the problem for you.