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  3. SOC Encounter: Problem with multiple clocks

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SOC Encounter: Problem with multiple clocks

Sirrius
Sirrius over 16 years ago

 Hello All,

 I have a design that involves two clocks (clk and sh_clk). However, after encounter synthesizes my design, it "splits" my clocks. 

The design consists of a kernel (Braun_Multiplier) and a wrapper for pads (Braun_Multiplier_WithPads), The input design header for the core reads:

module Braun_Multiplier(A_in, B_in, clk, sh_clk, clear, mult_output, cmp_out);

While the header for the core in the nelist generated by Encounter reads:

 module Braun_Multiplier (
    A_in,
    B_in,
    clk,
    sh_clk,
    clear,
    mult_output,
    cmp_out,
    clk_at_Pad__L2_N1,
    clk_at_Pad__L2_N2,
    clk_at_Pad__L2_N3 );

 I do not understand why the clk signal should be "split" like shown here. I am not sure whether this is correct or not.

 However, at the highest level of design (Braun_Multiplier_WithPads), the input design header to Enounter is:

module Braun_Multiplier_WithPads(A_ChipInp, B_ChipInp, clk_ChipInp,
     sh_clk_ChipInp, clear_ChipInp, mult_output_ChipOutp,
     cmp_out_ChipOutp);

 and in the netlist generated by Encounter, it is:

module Braun_Multiplier_WithPads (
    A_ChipInp,
    B_ChipInp,
    clk_ChipInp,
    sh_clk_ChipInp,
    clear_ChipInp,
    mult_output_ChipOutp,
    cmp_out_ChipOutp );

So, there seems to be consistency here.

In my synthesis script for Encounter, I have these lines:

setClockDomains -all \
  -clk clk sh_clk\
  -event R

 Can someone please point out to me whether this may be a problem? And if yes, what step will rectify it?

I wanted to attach the entire script that I use for synthesis, but, couldn't find "attach" option :(

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  • BobD
    BobD over 16 years ago

    Is Braun_Multiplier a partition in the design? If so you might want to try "setCTSMode -honorFence true":

    setCTSMode -honorFence {true | false}
    Controls whether CTS enters more than once into a fence in
    hierarchical designs.
    If you specify true, CTS does not create any extra ports for
    fences.
    Default:false (This means that CTS might create extra
    ports.)

    If Braun_Multiplier is not a partition, could you explain why the port addition that CTS is performing is problematic in your design scenario? Your explaintation might help me or someone else think of a solution to your problem.

    Hope this helps,
    Bob

     

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  • BobD
    BobD over 16 years ago

    Is Braun_Multiplier a partition in the design? If so you might want to try "setCTSMode -honorFence true":

    setCTSMode -honorFence {true | false}
    Controls whether CTS enters more than once into a fence in
    hierarchical designs.
    If you specify true, CTS does not create any extra ports for
    fences.
    Default:false (This means that CTS might create extra
    ports.)

    If Braun_Multiplier is not a partition, could you explain why the port addition that CTS is performing is problematic in your design scenario? Your explaintation might help me or someone else think of a solution to your problem.

    Hope this helps,
    Bob

     

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