Periodic reads - Xilinx Virtex6

Hello!

I read that the MPMC memory controller sends automaticly (1us period)
periodic read request to the DDR3 module to measure the phase detection.
(http://www.xilinx.com/support/answers/36719.htm -> Disabling Periodic
Reads During Writes)

I don't understand, that if the module is red in every 1us, than why is a
refresh logic implemented in the mpmc module? I think with every read the
content of a memory cell is refreshed.

In my work I want to measure memory retention time. I have modified the
refresh logic of the MPMC module. I have set non JEDEC refresh times, to
get memory data loss.

However I tested my system on a Virtex 6 board, and at very large refresh
period, the written data in the memory remains, without any loss.

Thank you for the answers!

Walter



	   
					
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