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Altera_Forum's avatar
Altera_Forum
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8 years ago

Cyclone 10 GX EMIF PLL clock input

After compiling a EMIF for Cyclone 10 GX, I noticed that it insists on using an external differential clock. Attempts at routing internal PLL output to pll_ref_clk input results in error. Does that mean I have to use an external LVDS oscillator, or loop a differential PLL output back to this?

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor

    Hi,

    --- Quote Start ---

    After compiling a EMIF for Cyclone 10 GX, I noticed that it insists on using an external differential clock

    --- Quote End ---

    • This is user configurable option in C10 EMIF IP under PLL refclk section.

    • Set in EMIF IP thenuse the IO standard that being set in EMIF IP.

    --- Quote Start ---

    Attempts at routing internal PLL output to pll_ref_clk input results in error

    --- Quote End ---

    • Yes, this is expected. C10 EMIF PLL refclk need to come externally from board.

    Best Regards,

    Anand Raj Shankar

    (This message was posted on behalf of Intel Corporation)

  • FHint's avatar
    FHint
    Icon for Occasional Contributor rankOccasional Contributor

    Hello,

    is this also applicable for Arria 10devices?

    I have found a source that states that in Quartus II 14.1 and earlier, this was also not possible for Arria 10 FPGA, but I have the same problem with Quartus 17.1.

    Why is it not possible to generate the EMIF ref clk with a PLL? The *_readme.txt file says, that the ref clk is optional.

    Best regards