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konapur_sateesh
Visitor
Visitor
2,034 Views
Registered: ‎06-12-2018

DDR4 Component Data Width limited to 8/16 bit in Zynq ultrascale+MpSoC

Hi, 

Can any one explain.. In Zynq ultrascale+MpSoc (PS) side it has DDR4 72bit interface. 64+8(ECC), 

My doubt is can we connect Single 64bit DRAM Component, to this DDR4 interface. (in vivado componet width shows 8/16 bit selection)

what makes difference if I connect x8,x16,x32,x64 devices.

If i get x64bit single DDR4 componet in the market, can i connect to the zynq.

 

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kveerama
Xilinx Employee
Xilinx Employee
2,002 Views
Registered: ‎05-07-2019

Hi,

To be clear

Zynq Ultrascale+ MPSoC

1.Are you saying DIMM as single x64 bit component?

DIMM is a single PCB with multiple DRAM modules/components. 64 bit DIMM can be either composed of 8 - x8 components or 4 - x16 components.

If it’s a DIMM, then you need to choose Components option in wizard as UDIMM or RDIMM based on your physical memory component.

Then you need to select the DRAM IC Bus Width ( data width of individual DRAM components on DIMM) option in wizard as 8 bit or 16 bit 

2.If you choose components, then you can use either

8-x8 components [which means each component width is 8 bit]

4 x16 components [which means each component width is 16 bit].

In the below figure of PS DDR Controller,

The ‘effective DRAM Bus width’ option is a total data width of DDR interface - 64 bit.

Based on your memory component, the DRAM IC Bus Width varies either 8 bit or 16 bit.

FDIMM1.png

 

Please have a look at the page 422 of UG1085.

FDIMM2.png

Thank you

Kind Regards,

Kasthuri

konapur_sateesh
Visitor
Visitor
1,961 Views
Registered: ‎06-12-2018

Hi Kasthuri,
Zynq has 64bit effective bus width . If we have any component with 64bit DDR4 device ,why the there is no option to select the this 64bit component in vivado ( 1x64bit),(2x32bit).
I feel there should be some clarity , why the devices are limited to 8,16 bit DDR4 support only in zynq ultrascale+MpSoC
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kveerama
Xilinx Employee
Xilinx Employee
1,907 Views
Registered: ‎05-07-2019

Hi,

The effective bus width of 64 bit is built using either 8 bit or 16 bit components.

In Vivado, DRAM IC Bus Width Per die is bus width per component [8 or 16 bit ].

Can you please send me the name of memory part which you are using?

Are you using DIMM?

Thank you.

Kind regards,

Kasthuri

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