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Altera_Forum's avatar
Altera_Forum
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16 years ago

RAMs synthesized away?

Hi,

I'm designing a system that reads data, store them in block RAM, and reads them from block RAM to feed some other design. However, when I was trying to synthesize the system, some of block RAMs (yeah, some of, not all) are synthesized away! To be exact, let me describe this way:

I have to load data to mem_parm1, mem_parm2, mem_x, mem_y, all of which are block rams. and they are read by a design called calc. After synthesize, mem_parm1 and mem_parm2 disappeared, only mem_x and mem_y are left.

The whole system passed functional simulation in Modelsim AE 6.4 starter version. Any suggestion on this? Thanks!

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Those RAM, that has no function in design, because no output depends on it's content or it's storage locations can't be addressed, can be expected to be synthesized away, as any other superfluous design parts.

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    thanks for the reply.

    I checked with all the related files, and I'm sure they are used - they passed functional simulation in Modelsim, and they worked well in Modelsim.