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LChen23's avatar
LChen23
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6 years ago

DDR4 CAS Latency （CL）Setting ？

Hi，

in Quartus , S10 external Memory, The Preset of DDR4-2666V CL20 Component 1CS 8Gb (1Gb x8) ， It seems the CL is 20,

But after I apply, it shows the CL is 23.

So , Why?

3 Replies

  • NurAida_A_Intel's avatar
    NurAida_A_Intel
    Icon for Frequent Contributor rankFrequent Contributor
    6 years ago

    Hi @LChen23​ ,

    Thank you for joining this Intel Community.

    Memory CAS latency setting= additive latency (AL) + the CAS latency (CL).

    This parameter specifies the number of clock cycles between the read command and the availability of the first bit of output data at the memory device. The value is depends on the memory device selected; you need to refer to the memory datasheet for details.

    Hope this helps.

    Thanks

    Regards,

    Aida

    • LChen23's avatar
      LChen23
      Icon for New Contributor rankNew Contributor
      6 years ago
      I find it in Datasheet. When enable BID ,the CL may change to 22,or 23… Best Regard 陈亮 18017280310