Hello, I am trying to use two inductors in my LNA as shown bellow to have a S-PARAM response so i will have S11 with lowerst possible values and tweak them for matching network. However when i ran EXPLORER live tuning with SParam as shown bellow i get no change in the response.

I know that Cgs and Cgd with the inductors having a resonance so by Varying L value i should have seen the change in resonance location,

But there is no change.Where did i go wrong?

Thanks. 

Hi, all

Recently, I meet the simulation error as the picture shows when I simulate my circuit with transient.  how can I solve this problem?

thank you~

Hello, i am trying to produce a gain circles on a simple transistor as shown bellow.

i have defined the range from 1 til 30 dB and i dont get any circle just dots in infinity?

Where did i go wrong?
Thanks.

Hello, i have built a matching network of 13dB gain and  NF as shown bellow step by step.(including all the plots and matlab )

its just not working at all,i am doing it exacly by the thoery

taking a point inside the circle-> converting its gamma to Z_source->converting gamma_s into gamma_L with the formulla bellow as shown in the matlab->converting the gamma_L into Z_L-> building the matching network for conjugate of Z_L and Z_c.Its just not working.

where did i got  wrong?

Thanks.

gamma_s=75.8966*exp(deg2rad(280.88)*i);
z_s=gamma2z(gamma_s,50);
s11=0.99875-0.03202*i
s12=721.33*10^(-6)+8.622*10^(-3)*i
s21=-188.37*10^(-3)+30.611*10^(-3)*i
s22=875.51*10^(-3)-100.72*10^(-3)*i
gamma_L=conj((s22+(s12*s21*gamma_s)/(1-s11*gamma_s)))
z_L=gamma2z(gamma_L,50)

Hello, There is a manual in matlab of matching LNA  shown in the link bellow.

In it as shown in the plot bellow they mention input and output circle plots.

Is there such option of input and output circle in cadence virtuoso?

https://www.mathworks.com/help/rf/examples/designing-matching-networks-part-1-networks-with-an-lna-and-lumped-elements.html

hi everyone, 

i'm trying to create a netlist for aging simulation. i would like to simulate how power, Gain and PAE (efficiency) are inlfuenced after 3 hours

i would be grateful if someone can correct my syntax in the netlist since i'm trying to make a sweep HB  simulation where the input power is the parameter.

i did it without any error for the sp (S parameters)  simulation.

you can see the images for both sp and hb simulation netlists. (from left to right: sp aging netlist; hb aging netlist)

i will be grateful if someone can provide me some syntax advices.

thanks,

best regards

Hi guys,

eDave,

I need to call (replay) a skill to combine some skills to ONE UI for more convenience and using as more easier.

Please help me to find the command to execute this.(code for example as more good)

HT,

For a project, we depend on capturing warnings. This works fine in Virtuoso but behaves differently in Allegro.

In our observations

Virtuoso:

>>> warn("Hello")

*WARNING* Hello

Allegro:

>>> warn("Hello")

*WARNING* Hello

But when we capture the warning:

Virtuoso:

>>> warn("Hello") getWarn()

"Hello"

Allegro:

>>> warn("Hello") getWarn()

"*WARNING* Hello"

This is a Problem for because we put an empty String in the warn and depend on the fact that no Warning results in an empty String but on Allegro the output always begins with *WARNING*

Is there a way to make the behavior consistent in both versions?

Hi supporters,

I got the following error while I run simulation with gate netlist using Cadence Incisive (v15.20):

----

ncsim(64): 15.20-s076: (c) Copyright 1995-2019 Cadence Design Systems, Inc.
ncsim: *E,DLOALB: Design library 'tcbnxxx' not defined while reading module tcbnxxx.MAOxxx:bv (VST).
ncsim: *F,NOSIMU: Errors initializing simulation 'alu_tb' 

----

xxx: standard library name.

My netlist design uses a cell "MAOxxx". I already included the library behavior model to compile using ncverilog, there is no error while compiling. But when I run with ncsim to execute the test, I got above error.

I tried to run with other vendors such as VCS or MTI, they worked.

Please help to understand the error.

Thanks.

I'm sending encrypted HDL to a customer who will use Cadence IES for simulation and was wondering how I should go about the encryption.

Does IES support the IEEE's P1735 and if so, where can I find Cadence's public key for performing the encryption?

Or is there an alternative solution that I can use for encryption?

Hi All,

I'm trying to understand checkpoint concept. When I found save and restart concept in cdnshelp, There is just describing about "$save" and "xrun -r "~~~".

and I found also the below link about save restart and it saves your time.

But I can't find any benefits from my experiment from save&restart article( I fully agree..the article)

Ok, So I'v got some experiment  Here.

1. I declared $save and got the below result as I expected within the simple UVM code.

In UVM code...

$display("TEST1");
$display("TEST2");
$save("SAVE_TEST");
$display("TEST3");
$display("TEST4");

And I restart at "SAVE_TEST" point by xrun -r "SAVE_TEST", I've got the below log

xcelium> run
TEST3
TEST4

Ok, It's Good what I expected.(The concept of Save and Restore is simple: instead of re-initializing your simulation every time you want to run a test, only initialize it once. Then you can save the simulation as a “snapshot” and re-run it from that point to avoid hours of initialization times. It used to be inconvenient. I agree..)

2. But The Problem is that I can't restart with modified code. Let's see the below example.

I just modified TEST5 instead of "TEST3"

$display("TEST1");
$display("TEST2");
$save("SAVE_TEST");
$display("TEST5"); //$display("TEST3");
$display("TEST4");

and I rerun with xrun -r "SAVE_TEST", then I've got the same log

xcelium> run
TEST3
TEST4

There is no "TEST5". Actually I expected "TEST5" in the log.From here We know $save can't support partially modified code after $save. 

Actually, through this, we can approach to our goal about saving developing time. 

So I want to know Is there any possible way that instead of re-initializing our simulation every time we want to run a test, only initialize it once and keep developing(debugging) our code ?

If we do, Could you let me know the simple example?

Hi all,

         I want to know how to run a regressive test in cadence and merge all ncsim .trn file of each test case into a single file to view all waveform in simvision. I am using Makefile to invoke the test case.

         eg:-

               test0:

                     irun -uvm -sv -access +rwc $(RTL) $(INTER) $(PKG) $(TOP) $(probe) +UVM_VERBOSITY=UVM_MEDIUM +UVM_TESTNAME=test0

             test1:

                   irun -uvm -sv -access +rwc $(RTL) $(INTER) $(PKG) $(TOP) $(probe) +UVM_VERBOSITY=UVM_MEDIUM +UVM_TESTNAME=test1

          I just to call test0 followed by test1 or parallel both test and view the waveform for both tests case.

        I new to this tool and help me with it

Hello folks,

Greetings.

One of my customer claims that he is using Cadence IES version 18.09.011 with Vivado 2019.2. The version of IES that we officially support with Vivado 2019.2 is 15.20.073. Though the tool is forward compatible, I am not sure what are the versions of IES that are released after 15.20.073. Could you please give me a list of the versions of Cadence IES released after 15.20.073 and which is the latest version as of now ?

Best regards,

Chinmay

Hi Team,

I would like to download "Incisive Metrics Center User Guide", I could not find in the cadence/support/manuals. Can you please provide me the link or path to download the same ? I am doing functional coverage with IMC. 

Thank You,

Mahesh

Hi,

I am facing this elaboration error when using Xcelium:

Command>

    xmverilog -v200x +access+r +xm64bit -f vlist -reflib plib -timescale 1ns/1ps

Log>

    xmelab: *E,CUVMUR (<name>.v,538|18): instance 'LUTP0.C GLAT3' of design unit 'tlatntscad12' is unresolved in 'worklib.LUTP0:v'.

I guess the plib was not referred to as the simulation configuration because the tlatntscad12 is included in plib.

The plib is compiled by INCISIVE 13.20 and I am using the Xcelium 19.30.

Please tell me the correct command on how to refer to the library directory compiled by different versions.

Thank you,

Hi,

I'm doing fault injection with ncsim and got stuck at the following (and not so useful) message: "ncsim: *E,FLTIGF: [FLT] Failed to inject fault at circuit_tb.U0.n2174." I already tried with other NETs, with SET, SA0, SA1, always the same error occurs.

My scripts so far, considering I already compiled the Verilog testbench and also the gates from the technology library (gate-level simulation):

#this runs ok

ncelab -work worklib -cdslib circuit/trunk/backend/synthesis/work/cds.lib -logfile ncelab.log -errormax 15 -access +wc -status -timescale 1ps/1ps worklib.circuit_tb -fault_file circuit/trunk/backend/synthesis/scripts/fi.list

#this runs ok
ncsim -fault_good_run -fault_tw 1ns:4ns -fault_work fault_db -fault_overwrite worklib.circuit_tb:module -input ../scripts/fs_strobe.tcl -exit

#this runs NOT OK
ncsim -fault_sim_run -fault_work fault_db worklib.circuit_tb:module -input ../scripts/injection.tcl -exit

After the above command I get: "ncsim: *E,FLTIGF: [FLT] Failed to inject fault at circuit_tb.U0.n2174."

Here are the files called from the commands above.

fi.list:

fault_target circuit_tb.U0.n2174 -type SET+SA1+SA0

fs_strobe.tcl:

fs_strobe circuit_tb.WRITE_OUT circuit_tb.PC_OUT[0]

injection.tcl:

fault -stop_severity 3 -inject -time 2ns -type sa1 circuit_tb.U0.n2174

I already checked the NETs with simvision, so their paths are correct.

Any ideas?

PS: I know about Xcellium, however, I don't have it yet.

We have talked about aspects of the in-design symbol edit application mode in the past. This is the environment specific to the Allegro Package Designer layout tools allowing you to work on symbol definitions directly in the context of your layout de...(read more)

Variants seem to be defined as present or not present.

Is there a variant that can assign different parts to the same reference designator? i.e.  R17 can be either 0 ohm 0805 jumper or 12k ohms 0805 resistor.

The simplest way I can think of is to use two parts with the same footprint and overlay them.

Is there a more functional way of doing this?  So that the variant would put the correct part in the BOM and the parts would of course have the same identical footprint.

Hi, I am in the middle of a design and had no problem going back and forth between schematics and layout. Now I am getting the error message below. I am using Cadence 17.2.

ERROR: Layout database has probably been reverted to an earlier version than that, which was used in the latest flow or the schematic database was synchronized with another board.

The basecopy file generated by the last back-to-front flow not found.

ERROR: Layout database has probably been reverted to an earlier version than that, which was used in the latest flow or the schematic database was synchronized with another board.

The basecopy file generated by the last back-to-front flow not found.

Error: CMFBC-1: The schematic and the layout constraints were not synchronized as the changes done since the last sync up could not be reconciled. Syncing the current version of the schematic or layout databases with a previous version would result in this issue. The  constraint difference report is displayed.

Continuing with "changes-only" processing may result in incorrect constraint updates.

Thanks for your input

Claudia

Hello all,

We are designing a backplane and in the design we are using some custom prefixes using the Advance Annotation tool. When annotating the occurances I get the following error:

ERROR(ORDBDLL-1224): The total number of components for prefix J0C exceeds the range supplied for it.
Increase the End value of the range.

Thanks in advance for the help

--Tom

Hello All,

Following is the einstein's puzzle solved by cadence Incisive92  (solved in less than 3 seconds -> FAST!!!!!!)

Thanks,

Vinay Honnavara

Verification engineer at Keyu Tech

vinayh@keyutech.com

 // Author: Vinay Honnavara

// Einstein formulated this problem : he said that only 2% in the world can solve this problem
// There are 5 different parameters each with 5 different attributes
// The following is the problem

// -> In a street there are five houses, painted five different colors (RED, GREEN, BLUE, YELLOW, WHITE)

// -> In each house lives a person of different nationality (GERMAN, NORWEGIAN, SWEDEN, DANISH, BRITAIN)

// -> These five homeowners each drink a different kind of beverage (TEA, WATER, MILK, COFFEE, BEER),

// -> smoke different brand of cigar (DUNHILL, PRINCE, BLUE MASTER, BLENDS, PALL MALL)

// -> and keep a different pet (BIRD, CATS, DOGS, FISH, HORSES)


///////////////////////////////////////////////////////////////////////////////////////
// *************** Einstein's riddle is: Who owns the fish? ***************************
///////////////////////////////////////////////////////////////////////////////////////

/*
Necessary clues:

1. The British man lives in a red house.
2. The Swedish man keeps dogs as pets.
3. The Danish man drinks tea.
4. The Green house is next to, and on the left of the White house.
5. The owner of the Green house drinks coffee.
6. The person who smokes Pall Mall rears birds.
7. The owner of the Yellow house smokes Dunhill.
8. The man living in the center house drinks milk.
9. The Norwegian lives in the first house.
10. The man who smokes Blends lives next to the one who keeps cats.
11. The man who keeps horses lives next to the man who smokes Dunhill.
12. The man who smokes Blue Master drinks beer.
13. The German smokes Prince.
14. The Norwegian lives next to the blue house.
15. The Blends smoker lives next to the one who drinks water.
*/




typedef enum bit [2:0]  {red, green, blue, yellow, white} house_color_type;
typedef enum bit [2:0]  {german, norwegian, brit, dane, swede} nationality_type;
typedef enum bit [2:0]  {coffee, milk, water, beer, tea} beverage_type;
typedef enum bit [2:0]  {dunhill, prince, blue_master, blends, pall_mall} cigar_type;
typedef enum bit [2:0]  {birds, cats, fish, dogs, horses} pet_type;




class Einstein_problem;

    rand house_color_type house_color[5];
    rand nationality_type nationality[5];
    rand beverage_type beverage[5];
    rand cigar_type cigar[5];
    rand pet_type pet[5];
        rand int arr[5];
    
    constraint einstein_riddle_solver {
    
        
    
        foreach (house_color[i])
            foreach (house_color[j])
               if (i != j)
                house_color[i] != house_color[j];
        foreach (nationality[i])
            foreach (nationality[j])
               if (i != j)
                nationality[i] != nationality[j];
        foreach (beverage[i])
            foreach (beverage[j])
               if (i != j)
                beverage[i] != beverage[j];
        foreach (cigar[i])
            foreach (cigar[j])
               if (i != j)
                cigar[i] != cigar[j];
        foreach (pet[i])
            foreach (pet[j])
               if (i != j)
                pet[i] != pet[j];
    
    
        //1) The British man lives in a red house.
        foreach(nationality[i])
                (nationality[i] == brit) -> (house_color[i] == red);
                
        
        //2) The Swedish man keeps dogs as pets.
        foreach(nationality[i])
                (nationality[i] == swede) -> (pet[i] == dogs);
                
                
        //3) The Danish man drinks tea.        
        foreach(nationality[i])
                (nationality[i] == dane) -> (beverage[i] == tea);
        
        
        //4) The Green house is next to, and on the left of the White house.
        foreach(house_color[i])        
                 if (i<4)
                    (house_color[i] == green) -> (house_color[i+1] == white);
        
        
        //5) The owner of the Green house drinks coffee.
        foreach(house_color[i])
                (house_color[i] == green) -> (beverage[i] == coffee);
                
        
        //6) The person who smokes Pall Mall rears birds.
        foreach(cigar[i])
                (cigar[i] == pall_mall) -> (pet[i] == birds);
        
        
        //7) The owner of the Yellow house smokes Dunhill.
        foreach(house_color[i])
                (house_color[i] == yellow) -> (cigar[i] == dunhill);
        
        
        //8) The man living in the center house drinks milk.
        foreach(house_color[i])
                if (i==2) // i==2 implies the center house (0,1,2,3,4) 2 is the center
                    beverage[i] == milk;
        
        
        
        //9) The Norwegian lives in the first house.
        foreach(nationality[i])        
                if (i==0) // i==0 is the first house
                    nationality[i] == norwegian;
        
        
        
        //10) The man who smokes Blends lives next to the one who keeps cats.
        foreach(cigar[i])        
                if (i==0) // if the man who smokes blends lives in the first house then the person with cats will be in the second
                    (cigar[i] == blends) -> (pet[i+1] == cats);
        
        foreach(cigar[i])        
                if (i>0 && i<4) // if the man is not at the ends he can be on either side
                    (cigar[i] == blends) -> (pet[i-1] == cats) || (pet[i+1] == cats);
        
        foreach(cigar[i])        
                if (i==4) // if the man is at the last
                    (cigar[i] == blends) -> (pet[i-1] == cats);
        
        foreach(cigar[i])        
                if (i==4)
                    (pet[i] == cats) -> (cigar[i-1] == blends);
        
        
        //11) The man who keeps horses lives next to the man who smokes Dunhill.
        foreach(pet[i])
                if (i==0) // similar to the last case
                    (pet[i] == horses) -> (cigar[i+1] == dunhill);
        
        foreach(pet[i])        
                if (i>0 & i<4)
                    (pet[i] == horses) -> (cigar[i-1] == dunhill) || (cigar[i+1] == dunhill);
                    
        foreach(pet[i])        
                if (i==4)
                    (pet[i] == horses) -> (cigar[i-1] == dunhill);
                    


        //12) The man who smokes Blue Master drinks beer.
        foreach(cigar[i])
                (cigar[i] == blue_master) -> (beverage[i] == beer);
        
        
        //13) The German smokes Prince.
        foreach(nationality[i])        
                (nationality[i] == german) -> (cigar[i] == prince);
        

        //14) The Norwegian lives next to the blue house.
        foreach(nationality[i])
                if (i==0)
                    (nationality[i] == norwegian) -> (house_color[i+1] == blue);
        
        foreach(nationality[i])        
                if (i>0 & i<4)
                    (nationality[i] == norwegian) -> (house_color[i-1] == blue) || (house_color[i+1] == blue);
        
        foreach(nationality[i])        
                if (i==4)
                    (nationality[i] == norwegian) -> (house_color[i-1] == blue);
        

        //15) The Blends smoker lives next to the one who drinks water.            
        foreach(cigar[i])            
                if (i==0)
                    (cigar[i] == blends) -> (beverage[i+1] == water);
        
        foreach(cigar[i])        
                if (i>0 & i<4)
                    (cigar[i] == blends) -> (beverage[i-1] == water) || (beverage[i+1] == water);
                    
        foreach(cigar[i])        
                if (i==4)
                    (cigar[i] == blends) -> (beverage[i-1] == water);
        
    } // end of the constraint block
    


    // display all the attributes
    task display ;
        foreach (house_color[i])
            begin
                $display("HOUSE : %s",house_color[i].name());
            end
        foreach (nationality[i])
            begin
                $display("NATIONALITY : %s",nationality[i].name());
            end
        foreach (beverage[i])
            begin
                $display("BEVERAGE : %s",beverage[i].name());
            end
        foreach (cigar[i])
            begin
                $display("CIGAR: %s",cigar[i].name());
            end
        foreach (pet[i])
            begin
                $display("PET : %s",pet[i].name());
            end
        foreach (pet[i])
            if (pet[i] == fish)
                $display("THE ANSWER TO THE RIDDLE : The %s has %s ", nationality[i].name(), pet[i].name());
    
    endtask // end display
    
    
endclass




program main ;

    initial
        begin
            Einstein_problem ep;
            ep = new();
            if(!ep.randomize())
                $display("ERROR");
            ep.display();
        end
endprogram // end of main

        

Hello All,

I have a situation where i want to implement 8 instance of some particular reg_file which all have many reg_def and reg_fld.

For example :
I have 8 instance of one DUT module (TEST0, TEST1,TEST2... TEST8), since its all are the instance so all the instance will have the sets of registers.. so to implement reg for one instance i can write code like..

extend vr_ad_reg_file_kind : [TEST0];
extend TEST0 vr_ad_reg_file {
keep size == 256;
};
reg_def EX_REG_TX_DATA TEST0 8’h00 {
// name : type : mask : reset value
reg_fld data : uint(bits:8) : RW : 0;
};

But now the issue is inside 1 instance i have around 256 registers, and i need to implement for all the 8 instance.... so can anyone suggest me how we can make instance for vr_ad_reg_file, otherwise i have to write same code for all the 8 instance.

Thanks

Just in time for the holidays, inside the posted tar ball is some code to solve 9x9 Sudoku puzzles with the Assertion-Driven Simulation (ADS) capability of Incisive Enterprise Verifier (IEV). Enjoy! Joerg Mueller Solutions Engineer for Team Verify

Try looking at www.solidwoodkitchen.co.uk. They have some amazing designs and prices.

Kitchen Design Manchester

ncsim will consume an increasing ammount of memory when a function has an output port that return an associative array which was not initialized. My simulator version is 12.10-s011.

Below is a code example to reproduce the failure. The code is inside a class (uvm_object):

function void a_function(output bit ret_val[int]);

// empty 

endfunction : get_cov

i had encountered error message like this before. 

but in liberate, i did not find the entry to input section info. 

Hi all,

Is there any tutorial which explains the process of plotting the ISF function for a certain oscillator ?

Thank you.

Hello,

I am trying to import multiple verilog modules defined in a single file with "`define" directive in the top using Verilog In. The code below is an example of what my file contains.

When I use the settings below to import the modules into a library, it imports it correctly but completely ignores all `define directive; hence when I simulate using any of the modules below the simulator errors out requesting these variables.

My question: Is there a way to make Verilog In consider `define directives in every module cell created? 

Code to be imported by Cadence Verilog In:

--------------------------------------------------------

`timescale 1ns/1ps
`define PROP_DELAY 1.1
`define INVALID_DELAY 1.3

`define PERIOD 1.1
`define WIDTH 1.6
`define SETUP_TIME 2.0
`define HOLD_TIME 0.5
`define RECOVERY_TIME 3.0
`define REMOVAL_TIME 0.5
`define WIDTH_THD 0.0

`celldefine
module MY_FF (QN, VDD, VSS, A, B, CK);

inout VDD, VSS;
output QN;
input A, B, CK;
reg NOTIFIER;
supply1 xSN,xRN;
buf IC (clk, CK);
and IA (n1, A, B);
udp_dff_PWR I0 (n0, n1, clk, xRN, xSN, VDD, VSS, NOTIFIER);
not I2 (QN, n0);

wire ENABLE_B ;
wire ENABLE_A ;
assign ENABLE_B = (B) ? 1'b1:1'b0;
assign ENABLE_A = (A) ? 1'b1:1'b0;

specify
$setuphold(posedge CK &&& (ENABLE_B == 1'b1), posedge A,  `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_B == 1'b1), negedge A, `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_A == 1'b1), posedge B, `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_A == 1'b1), negedge B, `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$width(posedge CK,1.0,0.0,NOTIFIER);
$width(negedge CK,1.0,0.0,NOTIFIER);
if (A==1'b0 && B==1'b0)
(posedge CK => (QN:1'bx)) = (1.0, 1.0);
if (A==1'b1 && B==1'b0)
(posedge CK => (QN:1'bx)) = (1.0, 1.0);
if (B==1'b1)
(posedge CK => (QN:1'bx)) = (1.0,1.0);

endspecify

endmodule // MY_FF
`endcelldefine

`timescale 1ns/1ps
`celldefine
module MY_FF2 (QN, VDD, VSS, A, B, CK);

inout VDD, VSS;
output QN;
input A, B, CK;
reg NOTIFIER;
supply1 xSN,xRN;
buf IC (clk, CK);
and IA (n1, A, B);
udp_dff_PWR I0 (n0, n1, clk, xRN, xSN, VDD, VSS, NOTIFIER);
not I2 (QN, n0);

wire ENABLE_B ;
wire ENABLE_A ;
assign ENABLE_B = (B) ? 1'b1:1'b0;
assign ENABLE_A = (A) ? 1'b1:1'b0;

specify
$setuphold(posedge CK &&& (ENABLE_B == 1'b1), posedge A,  `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_B == 1'b1), negedge A,  `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_A == 1'b1), posedge B,  `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$setuphold(posedge CK &&& (ENABLE_A == 1'b1), negedge B,  `SETUP_TIME, `HOLD_TIME, NOTIFIER);
$width(posedge CK,1.0,0.0,NOTIFIER);
$width(negedge CK,1.0,0.0,NOTIFIER);
if (A==1'b0 && B==1'b0)
(posedge CK => (QN:1'bx)) = (1.0, 1.0);
if (A==1'b1 && B==1'b0)
(posedge CK => (QN:1'bx)) = (1.0, 1.0);
if (B==1'b1)
(posedge CK => (QN:1'bx)) = (1.0,1.0);

endspecify

endmodule // MY_FF2
`endcelldefine

--------------------------------------------------------

I am using the following Cadence versions:

MMSIM Version: 13.1.1.660.isr18

Virtuoso Version: IC6.1.8-64b.500.1

irun Version: 14.10-s039

Spectre Version: 18.1.0.421.isr9

Hello,

I am using Virtuoso 6.1.7.

I am performing the parasitic extraction of a MOM cap array of 32 caps. I use Quantus QRC and I enable field solver. I select “QRCFS” for field solver type and “High” for field solver accuracy. The unit MOM cap is horizontally and vertically symmetric. The array looks like the sketch below and there are no other structures except the unit caps:

Rationally speaking, the capacitance values of the unit caps should be symmetric with respect to a vertical symmetry axis that is between cap16 and cap17 (shown with dashed red line). For example,

the capacitance of cap1 should be equal to the capacitance of cap32

the capacitance of cap2 should be equal to the capacitance of cap31

etc. as there are no other structures around the caps that might create some asymmetry.

Nevertheless, what I observe is the following after the parasitic extraction:

As it can be seen, the result is not symmetric contrary to what is expected. I should also add that I do not observe this when I perform parasitic extraction with no filed solver.

Why do I get this result? Is it an artifact resulting from the field solver tool (my conclusion was yes but still it must be verified)? If not, how can something like this happen?

Many thanks in advance.

Best regards,

Can

Hi,

This question is related to the constraint measurement criteria used by the Liberate inside view. I am trying to characterize a specific D flip-flop for low voltage operation (0.6V) using Cadence Liberate (V16). 

When the "define_arcs" are not explicitly specified in the settings for the circuit (but the input/outputs are indeed correct in define_cell), the inside view seems to probe an internal node (i.e. master latch output)  for constraint measurements instead of the Q output of the flip flop. So to force the tool to probe Q output I added following coder in constraint arcs :

# constraint arcs from CK => D
define_arc
-type hold
-vector {RRx}
-related_pin CP
-pin D
-probe Q
DFFXXX

define_arc
-type hold
-vector {RFx}
-related_pin CP
-pin D
-probe Q
DFFXXX

define_arc
-type setup
-vector {RRx}
-related_pin CP
-pin D
-probe Q
DFFXXX

define_arc
-type setup
-vector {RFx}
-related_pin CP
-pin D
-probe Q
DFFXXX

with -probe Q liberate identifies Q as the output, but uses Glitch-Peak criteria instead of delay degradation method. So what could be the exact reason for this unintended behavior ? In my external (spectre) spice simulation, the Flip-Flop works well and it does not show any issues in the output delay degradation when the input sweeps.

Thanks

Anuradha

Cadence Liberate Trio Characterization Suite, ARM-based Graviton Processors, and Amazon Web Services (AWS) Cloud have joined forces to cater to the High-Performance Computing, Machine Learning/Artificial Intelligence, and Big Data Analytics sectors. (read more)

The complexity and size of mixed-signal designs in wireless, power management, automotive, and other fast growing applications requires continued advancements in a mixed-signal verification methodology. An SoC, in these fast growing applications, incorporates a large number of analog and mixed-signal (AMS) blocks/IPs, some acquired from IP providers, some designed, often concurrently. AMS IP must be verified independently, but this is not sufficient to ensure an SoC will function properly and all scenarios of interaction among many different AMS IP blocks at full chip / SoC level must be verified thoroughly. To reduce an overall verification cycle, AMS IP and SoC verification teams must work in parallel from early stages of the design. Easier said than done! We will outline a methodology than can help.

AMS designers verify their IP meets required specifications by running a testbench they develop for standalone / out of-context verification. Typically, an AMS IP as analog-centric, hierarchal design in schematic, composed of blocks represented by transistor, HDL and behavioral description verified in Virtuoso® Analog Design Environment (ADE) using Spectre AMS Designer simulation. An SoC verification team typically uses UVM SystemVerilog testbech at full chip level where the AMS IP is represented with a simple digital or real number model running Xcelium /DMS simulation from the command line.

Ideally, AMS designers should also verify AMS IP function properly in the context of full-chip integration, but reproducing an often complex UVM SystemVerilog testbench and bringing over top-level design description to an analog-centric environment is not a simple task.

Last year, Cadence partnered with Infineon on a project with a goal to automate the reuse of a top-level testbench in AMS verification. The automation enabled AMS verification engineers to automatically configure setup for verification runs by assembling all necessary options and files from the AMS IP Virtuoso GUI and digital SoC top-level command line configurations. The benefits of this method were:

• AMS verification engineers did not need to re-create complex stimuli representing interaction of their IP at the top level
• Top-level verification stays external to the AMS IP verification environment and continues to be managed by the SoC verification team, but can be reused by the AMS IP team without manual overhead
• AMS IP is verified in-context and any inconsistencies are detected earlier in the verification process
• Improved productivity and overall verification time

For more details, please see Infineon’s CDNLlive presentation.

Verification is the top challenge in mixed-signal design. Bringing analog and digital domains together into unified verification planning, simulating, and debugging is a challenging task for rapidly increasing size and complexity of mixed-signal designs. To more completely verify functionality and performance of a mixed-signal SoC and its AMS IP blocks used to build it, verification teams use simulations at transistor, analog behavioral and real-number model (RNM) and RTL levels, and combination of these.

In recent years, RNM and simulation is being adopted for functional verification by many, due to advantages it offers including simpler modeling requirements and much faster simulation speed (compared to a traditional analog behavioral models like Verilog-A or VHDL-AMS). Verilog-AMS with its wreal continue to be popular choice. Standardization of real number extensions in SystemVerilog (SV) made SV-RNM an even more attractive choice for MS SoC verification.

Verilog-AMS/wreal is scalar real type. SV-RNM offers a powerful ability to define complex data types, providing a user-defined structure (record) to describe the net value. In a typical design, most analog nodes can be modeled using a single value for passing a voltage (or current) from one module to another. The ability to pass multiple values over a net can be very powerful when, for example, the impedance load impact on an analog signal needs to be modeled. Here is an example of a user-defined net (UDN) structure that holds voltage, current, and resistance values:

When there are multiple drives on a single net, the simulator will need a resolution function to determine the final net value. When the net is just defined as a single real value, common resolution functions such as min, max, average, and sum are built into the simulator.  But definition of more complex structures for the net also requires the user to provide appropriate resolution functions for them. Here is an example of a net with three drivers modeled using the above defined structural elements (a voltage source with series resistance, a resistive load, and a current source):

To properly solve for the resulting output voltage, the resolution function for this net needs to perform Norton conversion of the elements, sum their currents and conductances, and then calculate the resolved output voltage as the sum of currents divided by sum of conductances.

With some basic understanding of circuit theory, engineers can use SV-RNM UDN capability to model electrical behavior of many different circuits. While it is primarily defined to describe source/load impedance interactions, its use can be extended to include systems including capacitors, switching circuits, RC interconnect, charge pumps, power regulators, and others. Although this approach extends the scope of functional verification, it is not a replacement for transistor-level simulation when accuracy, performance verification, or silicon correlation are required:  It simply provides an efficient solution for discretely modeling small analog networks (one to several nodes).  Mixed-signal simulation with an analog solver is still the best solution when large nonlinear networks must be evaluated.

Cadence provides a tutorial on EEnet usage as well as the package (EEnet.pkg) with UDN definitions and resolution functions and modeling examples. To learn more, please login to your Cadence account to access the tutorial.

This blog discusses key features of concurrently editing a hierarchical cellview.(read more)

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