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Contributor
Contributor
381 Views
Registered: ‎05-22-2018

SD card : Longer trace lengths & line driver

Dear All,

My custom board design has a SD card 2.0 for booting the XCZU21DR SoC. As per SD card's general routing guidelines maximum trace length for the SD lines is to be 3000 mils to 4000 mils.

In our case we can not go below 6000 mils. As a solution to this :

1. Can I use a line driver/buffer gate for CLOCK line  to compensate? Is this a good idea ?

2. Do I need to buffer all signals or just CLOCK will do?

Thanks.

--Vikas

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Teacher
Teacher
374 Views
Registered: ‎07-09-2009

Re: SD card : Longer trace lengths & line driver

You have two choices,

   you can run on 'best parctice' or on simulation

 

personaly, I'd recomend you simulat the board, IBIS models are you  friend here.

 

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Xilinx Employee
Xilinx Employee
321 Views
Registered: ‎10-11-2011

Re: SD card : Longer trace lengths & line driver

I agree on the IBIS models. Be sure there are no weird reflection on the zynq side of the SD clock. It's used to sample the data back and a reflection there can really messed up your sampling.

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