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Altera_Forum's avatar
Altera_Forum
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17 years ago

How to define 2-port RAM output (old data or don't care)

Hello,

does anyone know how to define 2-port RAM output(q) for read-during-write? I am using simple 2-port RAM(1 port with read and write) with separate read and write clock(wr_clk, rd_clk) and I just can't choose either old_data or don't care because the selection page was skipped by megawizard.. :(

any help would be much appreciated..

thanks!

2 Replies

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

    Hi konyemko,

    the "Read-During-Write" only makes sense when using the same clocks for read and write. When using separate clocks for both sides, you can not assume a relationship between the two clocks and therefore you can not select the "Read-During-Write" option in this case.

    Hope this helps...
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    thanks Sanmao, i understand now. I have to choose single clock for read/write, then i can select either old_data or don't care for read-during-write.

    thanks! :)