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Charactiresation SRAM with liberate MX

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Dima_M

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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.
 

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.
 

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