Cadence® system design and verification solutions, integrated under our System Development Suite, provide the simulation, acceleration, emulation, and management capabilities.
System Development Suite Related Products A-Z
Cadence® digital design and signoff solutions provide a fast path to design closure and better predictability, helping you meet your power, performance, and area (PPA) targets.
Full-Flow Digital Solution Related Products A-Z
Cadence® custom, analog, and RF design solutions can help you save time by automating many routine tasks, from block-level and mixed-signal simulation to routing and library characterization.
Overview Related Products A-Z
Driving efficiency and accuracy in advanced packaging, system planning, and multi-fabric interoperability, Cadence® package implementation products deliver the automation and accuracy.
Cadence® PCB design solutions enable shorter, more predictable design cycles with greater integration of component design and system-level simulation for a constraint-driven flow.
An open IP platform for you to customize your app-driven SoC design.
Comprehensive solutions and methodologies.
Helping you meet your broader business goals.
A global customer support infrastructure with around-the-clock help.
24/7 Support - Cadence Online Support
Locate the latest software updates, service request, technical documentation, solutions and more in your personalized environment.
Cadence offers various software services for download. This page describes our offerings, including the Allegro FREE Physical Viewer.
Get the most out of your investment in Cadence technologies through a wide range of training offerings.
This course combines our Allegro PCB Editor Basic Techniques, followed by Allegro PCB Editor Intermediate Techniques.
Virtuoso Analog Design Environment Verifier 16.7
Learn learn to perform requirements-driven analog verification using the Virtuoso ADE Verifier tool.
Exchange ideas, news, technical information, and best practices.
The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information.
It's not all about the technlogy. Here we exchange ideas on the Cadence Academic Network and other subjects of general interest.
Cadence is a leading provider of system design tools, software, IP, and services.
I'm having problems with vias, which are exportet to GDS files.
I exportet the chip layout from Encounter to a GDS file: streamOut chip.gds.gz -mapFile ../setup/gds2.map -libName DesignLib -stripes 1 -units 1000 -mode ALL
The GDS file is hierarchical and instanciates standard cells, io pad cells and vias, but does not define them, because Encounter only has the coarse definitions from the LEF files. Thats fine, because they will be used from Virtuoso.
Then I've imported this GDS file into ICFB:CIW: File -> Import -> Stream... Input File: /home/glaser/chip/routing/run/chip.gds.gz Top Cell Name: chip Output Library Name: iac2010 Options: Retain Reference Library (No Merge) [X] Do Not Overwrite Existing Cell [X]
Everything works fine, because the referenced standard cells are now taken from the according library in the library manager. When I open the layout, all cells and vias are shown properly.
When the layout is exported from ICFB again, the "Individual Cell Statistics" complains (VIA2_C$$175108140/layout) -- (referenced, but not defined, no data created). (VIA3_C$$175104044/layout) -- (referenced, but not defined, no data created). (VIA1_C$$175100972/layout) -- (referenced, but not defined, no data created).
When loading the GDS file with "calibredrv", I get similar messages: WARNING: Cell VIA1_C$$175100972 is referenced but not defined. Empty cell used. WARNING: Cell VIA2_C$$175108140 is referenced but not defined. Empty cell used. WARNING: Cell VIA3_C$$175104044 is referenced but not defined. Empty cell used.When I zoom in at places with lots of wires, no vias are shown.
My analysis has shown, that the GDS file exported by Encounter uses for the three via types (4 metal process) instances from the technology library. The via cells are called VIA1_C, VIA2_C and VIA3_C. The layout shown by Virtuoso shows lots of instances of these vias.
All these vias are PCells for which the parameters yBias, xBias, yPitch, xPitch, column, row, l, and w can be modified.
When exporting the layout, for every parameter combination a unique definition with a unique name is created (therefore the suffix '$$123456789', which number changes every time of export). Fortunately there is only one combination of parameters for each via type.
In the exported GDS file, the vias are instanciated with the suffix (e.g. 'VIA1_C$$175100972'). The cell definition OTOH are embedded without the suffix (e.g. 'VIA1_C').
I've tried all combinations of options of the export dialog, but none has helped.
I've also done an additional test: I've drawn a layout by myself in Virtuoso (without import) with paths and vias (Create -> Path, draw a line, then press [F3] and choose another layer). When then editing the via instance properties ([q] key), the option "Parameter" is deactivated. OTOH when I instanciate a via directly from the technology library, then this option is enabled and all the parameters mentioned above can be edited. When this layout is then exported to a GDS file, all vias get their own suffix (different ones for automatically and manually instanciated). The via cell definition as well as the via instances use the suffix correctly. So for layouts drawn completely in Virtuoso, everything works ok.
For the imported layout, all vias have the "Parameter" option enabled and proper values are set. When exported, the instances get a suffix, but the cell definitions do not. This is why they are wrongly referenced.
Could you please help me find and solve the problem?
I'm using a 350nm process with 4 metal layers, Cadence First Encounter v08.10-s273_1 und Cadence Virtuoso 220.127.116.110.6.143.
I was pointed to a solution which now works. Please find the solution here:
The solution is simple: edit (e.g. add a path and then delete it again) and save the imported cell. This seems to correct something so that the final export works properly.