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Adventurer
Adventurer
4,229 Views
Registered: ‎04-20-2009

Supported LPDDR2 devices

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Hi all!

Just a quick survey before we commit our design to PCB: Does anyone have experience with LPDDR2 devices other than the two pre-selectable in XPS (MT42L64M32D1KL-25 (2 Gbit) and MT42L128M32D1KL-25 (4 Gbit). Both are single die, single channel, 1 rank per channel devices. The device we originally intended to use was a lot smaller, MT42L16M32D1AC-25 (512 Mbit), also a single die, single channel, 1 rank per channel device. I assumed it would be OK and altered the settings in XPS accordingly, but now the SW guys are concerned about space so they want to stick on the MT42L32M32D2AC-25 (1 Gbit). This is a dual die, single channel, 1 rank per channel device. Does anyone see any problems with that?

 

BTW, could someone explain the term “rank” in this context to a BDU (Brain Dead User)? It says in the TRM “Maximum Ranks” = 1, but the term is unfamiliar to me. Not that I think it matters, all devices above are single rank.

 

Thanks!

/Lars

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Visitor
Visitor
5,473 Views
Registered: ‎02-27-2013

I see no issues with that part.

 

A rank roughly translates to 'number of chip-selects.'  Please take a look at the Micron datasheet "U80M_4Gb_mobile_lpddr2_s4" (find part number MT42L256M32D2LG-25 WT).  Figures 4 to 10 will show various rank and channel configurations.  Any configuration that matches the I/O of figure 4 should be Zynq-compatible.

 

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Xilinx Employee
Xilinx Employee
4,221 Views
Registered: ‎07-11-2011

Hi,

 

You can select one  among the available parts that matches your desired part as Base part and vary timing parameters and address signals to achieve your required LPDDR2 part.

 

MPMC/MIG has no specific meaning other than the industry standard, it is just set of DDR chips connected to a single CS.

Please refer wiki, if you are still unclear let us know.

http://en.wikipedia.org/wiki/Memory_rank

 

 

Hope this helps

 

Regards,

Vanitha.

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Highlighted
Visitor
Visitor
5,474 Views
Registered: ‎02-27-2013

I see no issues with that part.

 

A rank roughly translates to 'number of chip-selects.'  Please take a look at the Micron datasheet "U80M_4Gb_mobile_lpddr2_s4" (find part number MT42L256M32D2LG-25 WT).  Figures 4 to 10 will show various rank and channel configurations.  Any configuration that matches the I/O of figure 4 should be Zynq-compatible.

 

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Adventurer
Adventurer
4,210 Views
Registered: ‎04-20-2009

Thanks!

That cleard things up for me. I hope to be able to post back in a few weeks to confimt that it worked.

/Lars

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