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SYadl2's avatar
SYadl2
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5 years ago

we have below two questions 1.Can we use fpll in arria10 devices for user logic clock generation. we chose fpll as the normal pll is not supported fractional divider value 2. Mentioned second question below

2. while generating two frequencies(360,156.25) from one pll we are not able to get exact frequency in one of the frequency. do v need to use seperate plls for generating these two frequencies.

3 Replies

  • SreekumarR_G_Intel's avatar
    SreekumarR_G_Intel
    Icon for Frequent Contributor rankFrequent Contributor

    Answer #1 : yes , Arria 10 FPLL can be used in Fabric side.

    Answer #2 : Can you check that you are getting any warnings after compliation ; My past experience I see valuses such as 306.7 FPLL vco not able to converge where 306.5 was working fine.

    • SYadl2's avatar
      SYadl2
      Icon for New Contributor rankNew Contributor

      ​1. we are using fPLL in Core Mode. But we are getting below error as we have provided input from FPGA pin.

      Error(11215): Input port "REFCLK" of "CMU_FPLL_REFCLK_SELECT" cannot connect to PLD port "O" of "IO_INPUT_BUFFER" for atom "fpga_clk~input".

      To avoid above error, Do we need to provide internal clock signal to input of fPLL instead of PAD clock.

      We have created one simple counter logic, to make sure fPLL works for user logic.

      Clock path is as below.

      FPGA pin to fPLL input

      Output clock from fPLL is used for running a 4 bit counter. Counter bits are given to on board LEDs.

  • YuanLi_S_Intel's avatar
    YuanLi_S_Intel
    Icon for Regular Contributor rankRegular Contributor

    This thread will be transitioned to community support. If you have a new question, feel free to open a new thread to get the support from Intel experts. Otherwise, the community users will continue to help you on this thread. Thank you