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glen-7's avatar
glen-7
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8 days ago

Agilex-5: WCK to CK Ratio for LPDDR5

In general, LPDDR5 memory devices support two ratios for the WCK to CK clocks: 4:1 and 2:1. The Micron datasheets refer to this ratio as 'CKR'. From the perspective of the memory datasheet, there is apparent freedom to select one ratio or the other, although there is a requirement to be in 2:1 mode during the 'WCK2CK Leveling Procedure'. The ratio can be changed on the fly.

The Altera EMIF seems to be enforcing a 2:1 ratio, and it seems like there is no option to select a 4:1 ratio. Do you know if the CKR can be changed in the EMIF configuration, or is this hard-coded to be 2:1?

Programmable Logic Device

1 Reply

  • AdzimZM_Altera's avatar
    AdzimZM_Altera
    Icon for Regular Contributor rankRegular Contributor
    2 days ago

    Hi glen-7 ,

     

    I don't this can be changed. The current supported frequency is 1066MHz and 800MHz for group B device.

    If the device can support higher frequency (>1600MHz), then the 4:1 ratio might be available.

     

    Regards,

    Adzim