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  1. #1
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    Charactiresation SRAM with liberate MX

    Hello,

    I am trying to characterize SRAM with Liberate and I have some problem with definition of user arc.
    I want to skip a probe of some node in setup arc
    Code:
    define_arc \
        -type setup \
        -attribute { altos_mx_autoprobing_skip_probe "WE" } \
        -attribute { altos_mx_autoprobing_skip_rel_probe "HCLK" } \
        -related_pin_dir R -pin_dir R  \
        -related_pin { HCLK } \
        -pin { SRAMWEN } \
        $cell_name
    
    define_arc \
        -type setup \
        -attribute { altos_mx_autoprobing_skip_probe "WE" } \
        -attribute { altos_mx_autoprobing_skip_rel_probe "HCLK" } \
        -related_pin_dir R -pin_dir F  \
        -related_pin {HCLK} \
        -pin {SRAMWEN} \
        $cell_name
    but Liberate chooses it for characterization.

    I specify my mpw arc
    Code:
    define_measure \
    	-name      {mpw_h_wen_data} \
        -keep      max \
        -duration  1 \
        -trig      {HCLK} \
        -trig_dir  rise \
        -trig_val  1.65 \
        -trig_e    {first} \
        -targ      {I0_1.Data_1} \
        -targ_dir  rise \
        -targ_val  2.8 \
        -targ_e    {first} \
        -max_val   "1e-08" \
        -min_val   "0" \
        -targ_type "delay" \
    	-when 	   "SRAMWEN" \
    $cell_name
    
    define_arc \
        -type mpw \
    	-measure mpw_h_wen_data \
        -pin_dir R  \
        -related_pin {HCLK} \
        -pin {HCLK} \
        $cell_name
    This path is larger than Liberate's automatic arc, but it is not measured and result absent in measure.rpt and measure.rpt.fastsim file. Consequence Liberate is take value from Liberate's automatic arc.

    Leakage current from characterization to larger than simulation.

    •   Alt21st April 2017, 18:04

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  2. #2
    Advanced Member level 2
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    Re: Charactiresation SRAM with liberate MX

    My suggestion is to do the reverse-engineering flow, where you load an existing .lib file and use arcs from it. Silicon smart supports that, I assume Liberate does it as well.
    Really, I am not Sam.



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