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Registered: ‎03-12-2010

Simulation of DDR2 with ISim


After generating a core for DDR2 using MIG (ISE 11.5, MIG v3.3, DDR2: MT47H32M16 (as on Spartan-3AN Start Kit)) I created a testbench in order to simulate the behaviour; it all works quite fine, but I still have a problem with the command-signals ISim shows:

Referring to the manual of the memory-chip I analyzed the init-sequence and the first read-command; but while doing so I wondered that cntrl0_ddr2_cs_n is always "0", in fact logic H. But this does not lead to any read command (which can be seen on Table 36 in the memory-datasheet).

Where is the error placed? Somewhere in the simulation or rather in my mind?





After studying the simulation for many times I also have a problem concerning the burst-length; as seen on figure 34 (MR Definition) in the datasheet of the memory, the bits A[2] downto A[0] are responsible for the burst-length. There is a choice between 4 (010) or 8 (011); but the simulation shows the pattern (100) which is definitely not defined ("Reserved"). So, what is the effective burst length? Why does the testbench deliver such false simulation results?

Message Edited by fthillma on 03-22-2010 01:23 AM
Message Edited by fthillma on 03-22-2010 01:24 AM
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