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Altera_Forum's avatar
Altera_Forum
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13 years ago

altera_reset_synchronizer_int_chain_out

Hi all

i builted a large design for Startix IV 530.

i'm using up to 630 DSP blocks in my design.

if let it run (compile) normaly, i get "altera_reset_synchronizer_int_chain_out" timming falling paths.

if i add set_false_path command to my project SDC file, i get an error about the amount of DSP blocks

"can not find legal placement for <x> dsp blocks".

how can i solve this issue?

inon_y

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    --- Quote Start ---

    Hi,

    how are you setting the false path?

    --- Quote End ---

    set_false_path \-from {..|altera_reset_synchronizer_int_chain_out} \-to [all_registers]
  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    That's not good, your just sweeping issues under the "false path" rug.

    You should set a false path between the reset input signal and the synchronization registers _IF_ the reset signal is asynchronous in respect to the target clock.

    If you still get failing paths after that, then you have a problem that affects timing and you need to take care of it that way.

    Maybe the reset output needs to be driven to a global clock signal and Quartus is failing to do so automatically?