How to 32bit DDR2 in CycloneIII development kit?

Hi,

I did more test trying to use the other memory chips

not used in reference design (for example, U25A in DDR2_BOTTOM).

I switched DQ width back to 16 and make the following pin assignment modifications.

mem_dm[1..0] <= ddr_dm[3..2]

mem_dq[15..0] <= ddr_dq[31..16]

mem_dqs[1..0] <= ddr_dqs[3..2]

The same error (shown in earlier message) will show up.

Once I switched back to the original chip (U26A) by assigning

mem_dm[1..0] <= ddr_dm[1..0]

mem_dq[15..0] <= ddr_dq[15..0]

mem_dqs[1..0] <= ddr_dqs[1..0],

then every is fine.

What is problem when memory chip U25A is used?

Thanks,

gl888