Subthreshold Standard Cells Characterization by Liberate

Hi

creating template file from scratc :

Defining supplies, transition and delay thresholds, setting cell list, delay_template, power_template, const_template shold be manually created since these are user defined.This is clear.

However my question is wether defining cells, leakage and arc for all cells of the library (!) have to be manually craeted in the template file or it will be automatically generated?

In the manual scripting case: then what is the sense of

"It is not required to define functionality or arcs for standard cell libraries. Liberate uses the patented technology “Inside-View”, to determine the functionality and the required arcs."?!

   * as we see in the following script, lots of lines are necessary for a cell with only two inputs!

In the automatic case:, how can it be generated (with which commands)?

Kind regards

BarPouy

if {[ALAPI_active_cell "cell_name"][ {

     define_cell \

            -inpit { A1 A2 } \

           -output { Y } \

           -pinlist  { A1 A2 Y } \

           -delay delay_template \

         power power_template \

     cell_name

define_leakage -when "!A1 * !A2" cell_name
define_leakage -when "!A1 * A2"  cell_name
define_leakage -when "A1 * !A2"  cell_name
define_leakage -when "A1 * A2"   cell_name

# power arcs from  => A1  hidden
define_arc \
       -type hidden \
       -when "!A2" \
       -vector {Rxx} \
       -pin A1 \
       cell_name

# power arcs from  => A1  hidden
define_arc \
       -type hidden \
       -when "!A2" \
       -vector {Fxx} \
       -pin A1 \
       cell_name

# power arcs from  => A2  hidden
define_arc \
       -type hidden \
       -when "!A1" \
       -vector {xRx} \
       -pin A2 \
       cell_name

# power arcs from  => A2  hidden
define_arc \
       -type hidden \
       -when "!A1" \
       -vector {xFx} \
       -pin A2 \
       cell_name

# delay arcs from A1 => Z positive_unate combinational
define_arc \
       -vector {RxR} \
       -related_pin A1 \
       -pin Z \
       cell_name

# delay arcs from A1 => Z positive_unate combinational
define_arc \
       -vector {FxF} \
       -related_pin A1 \
       -pin Z \
       cell_name

# delay arcs from A2 => Z positive_unate combinational
define_arc \
       -vector {xRR} \
       -related_pin A2 \
       -pin Z \
       cell_name

# delay arcs from A2 => Z positive_unate combinational
define_arc \
       -vector {xFF} \
       -related_pin A2 \
       -pin Z \
       cell_name

Hi,

I guess, the template file could be genarate partly by adding the folloeing lines to the template file after defining delay_, power_ and constraint_template

set inputs  {I A1 A2 A3 A4 D SI SE CDN SD}
set outputs {Z ZN Q}
set clocks  {CP}
set asyncs   {}

define_cell \
        -input $inputs  -output $outputs  -clock $clocks  -async $asyncs \
        -constraint  constraint_template  \
        -delay       delay_template      \
        -power       power_template      \
        $cells

However, I'm not sure, that this lesds to generate all arcs

BarPouy

Hi Guangjun

While char I get ERROR

ERROR (LIB-902): Failed to open file '~netlist/extracted/spice/rctyp/    .sp' for read. Check directory/file paths and permissions and rerun.
ERROR (LIB-902): Failed to open file '~netlist/extracted/spice/rctyp/    .sp' for read. Check directory/file paths and permissions and rerun.

All paths have an access right of drwxr-sr-x and all spice files -rw-r--r--

What is the reason of this ERROR?

Thanks

Kind regards

BarPouy

Can you try to open this file with the exact name, '~netlist/extracted/spice/rctyp/    .sp' ? the space before .sp is the cause. If you are using cell-based netlist, make source there is no space after each '\'  where you define the cell list?

Regards,

Guangjun 

Guangjun Cao said:

make source

sorry for the type, 'make sure'

Thnak you Guangjun,

exactly, that was the reason.

Reagards

BarPouy

Hi Guangjun,

Now it looks better!

In order to generate arc automatically in the template I added in my basic template the following scrip, after defining slew, measure_slew and delay with set_var and after that set cell_list and defining index1 / index2

set inputs  {I A1 A2 A3 A4 I0 I1 S D SI SE CDN SD}
set outputs {Z ZN Q}
set clocks  {CP}
set asyncs   {}

define_cell \
        -input $inputs  -output $outputs  -clock $clocks  -async $asyncs \
        -constraint  constraint_template_11x11 \
        -delay       delay_template_11x11      \
        -power       power_template_11x11      \
        $cell_list

However the inputs list means the total inputs of all cells of the library, NOT of each cell. Now Librate generates a lot of ERROR, e.g. like this

Initializing Spice
*Info* No global model has been read in. Will expect model defined inside instance.
ERROR (LIB-520): (char_library): The pin 'A3' is not defined for cell 'AN2d1'. This cell will be ignored. Check the netlist and make sure it is consistent with 'define_cell' command.
ERROR (LIB-203): (char_library): Cell 'AN2d1' is scheduled for characterization but has no netlist, has an empty subckt or has no port on the subckt. This cell will be skipped. Check the netlist and rerun.

What is my mistake?

Kind regards

BarPouy

BarPouy said:

Guangjun

I never use $variable to for pins. However, it should not cause error, I just tested with latest release. I do not any issue in the commands you shared. what you shared might not be related to the question you asked.

The two errors are different. I suggest you check the netlist first. make sure you do not have leafcell related warning or error.

try to do a test run with AN2d1 alone and go through the whole logfile. you might have overlooked something.

I will not be available until Monday next week.

Regards,

Guangjun 

based on your comments in another post, the problem might come from define_arc -vector command. -vector needs a -pinlist in define_cell. if you want arcs to be auto-generated, remove all define_arc command. if the problem still exists, use define_cell for each cell, replace $variable with real names. start with one cell that has problem. you may remove all other cells from $cells list, or use char_library -cells {your_cellname}  to selective characterize some cells. please read the manual.

I am on vacation, hence delay in response.

Regards,

Guangjun

Thank you Guanjun!

As you suggested, I tried with define_cell for one cell. It seems to function. However there is one ERROR (max load of AN2d1:Z is less than min defiened load). I have to wait on free license and I will try agin.

Regards

BarPouy