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crystal9182
Newbie
Newbie
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Registered: ‎03-03-2021

VCU118 DDR4 use issue

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Hi,

  I am trying to configure DDR4 MIG IP with the VCU118 evaluation board. Our design requires AXI interface, but with AXI enabled, the DDR4 data width cannot reach 80bit. Is there any solutions to this issue? And can I only use DQ[71:0] of the DDR4 on the VCU118 board?

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rpr
Moderator
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Registered: ‎11-09-2017

Hi @crystal9182 

Out of the 80-bit width you use can 64-bit and rest bits are not compulsory to use. Overall memory size with 64bit is smaller that's it.

Regards
Pratap

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ryanjohnson8
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Registered: ‎05-30-2017

With the AXI interface, you'll only be able to get 64 bits. If you want the full 80, you'll need to turn off the AXI interface so it bypasses the AXI logic and gives you the native MIG ports, which use a protocol similar to AXI.

crystal9182
Newbie
Newbie
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Registered: ‎03-03-2021
I would like to know what will happen if I only connect these 64 bits to DDR4 IO pins of the board and leave other 16 bits float?
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rpr
Moderator
Moderator
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Registered: ‎11-09-2017

Hi @crystal9182 

Out of the 80-bit width you use can 64-bit and rest bits are not compulsory to use. Overall memory size with 64bit is smaller that's it.

Regards
Pratap

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View solution in original post

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rpr
Moderator
Moderator
265 Views
Registered: ‎11-09-2017

Hi @crystal9182 

Out of the 80-bit width you use can 64-bit and rest bits are not compulsory to use. Overall memory size with 64bit is smaller that's it.

Regards
Pratap

Please mark the Answer as "Accept as solution" if information provided is helpful.

Give Kudos to a post which you think is helpful.
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