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Visitor
Visitor
4,993 Views
Registered: ‎04-20-2016

How to use 2 memory components with PS DDR controller on zynq?

I have two MT41K256M16RE125 DDR3 with16-bit bus 512MB and total 32 bit bus width to get 1GB. both components are populated on PCB but Linux shows only 512 GB.

I found Two_rank_cfg register /reg_ddrc_addrmap_cs_bit0 but I don't know what value to use or is it solving my problem at all. (if yes, should I change it in HWDEF folder or is there a driver for it?)

Is two-rank DDR3 possible using PS controller or I have to use MIG? (I prefer to not use MIG as it doesn't let me use current DDR clock I'm using 533 MHz)

 

Thanks in advance for any help!

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Xilinx Employee
Xilinx Employee
4,972 Views
Registered: ‎07-11-2011

Re: How to use 2 memory components with PS DDR controller on zynq?

@panizb

 

MT41K256M16RE125 is a X16 single rank device, if you have two of them you can increase the data width to X32 in PS DDR data with options to achieve 1GB

Also MIG does support 533Mhz, please check in Vivado 2016.2

 

Hope this helps

 

-Vanitha 

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Visitor
Visitor
4,941 Views
Registered: ‎04-20-2016

Re: How to use 2 memory components with PS DDR controller on zynq?

Thanks Vanitha for your reply. bus data-width  is set to 32-bit but Linux only reports 512MB not 1GB. There are registers for DDR two rank configuration & address-map-bit0 but I'm not sure what values need to be used or is it really what I need. I attached a pic of PS DDR settings. 

 

thx

ddr.JPG
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Observer
Observer
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Registered: ‎11-30-2017

Re: How to use 2 memory components with PS DDR controller on zynq?

Did you ever find out how to get the full 1GB of DDR space? 

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