Get email delivery of the Cadence blog featured here
In System in Package (SiP) 16.3, the co-design die flow introduced the distributed co-design flow concept, where there is no direct interaction with I/O Planner. Die information flowing between Encounter and SiP Layout is done via a die abstract. In flows up through 16.3, you first need to load the LEF files for the cell library used by the IC design into the LEF Library Manager and create the Condensed Macro Library (CML) files. The CML files would need to be updated anytime the LEF files changed. In the flow for Allegro Package Designer (APD) 16.5, Encounter will generate die abstracts including information for all layers for each pin of each I/O cell macro that is used in the die. The intent of the 16.3 distributed co-design flow using the die abstract was to provide the necessary library information inside the die abstract to allow us to eliminate the use of LEF/CML files in the co-design flow. However, there was no mechanism provided in that flow for the user to identify the die pins and connection pins, so LEF files were still needed. In 16.5 we support the distributed co-design flow allowing the user to choose to continue to load LEF/CML, create CML based on die abstract file, or not create CML at all. Not requiring creation of CML files would be the default mechanism.
Read on for more details …
The intent of this feature is to provide IC library manager capabilities needed to support a new distributed co-design flow option. The only difference from a current distributed co-design flow is that by default no additional library information other than provided in die abstract file is needed, and no IC Library Manager user interface options are needed. If the user chooses, they can also either create a CML file based on die abstract file, which again is a new capability, or use the same 16.3 based flow of creating a CML file based on LEF library.
Add Co-design Die from Die Abstract file (simple mode without IC Library Manager UI)• The Add Co-design Die command is invoked.• The New Design from Die Abstract file tab is selected.• User enters or browses to point to a Die Abstract file.• The design name (read from the Die Abstract file, and becomes the component name) appears on the form.• User presses OK button to add the die to the drawing, or Cancel to abort command.• The die placement form appears, an image of the die appears on the cursor and the user can place the die into the SiP design.
Add Co-design Die from Die Abstract file (cml file to be created based on Die Abstract file)• The Add Co-design Die command is invoked.• The New Design from Die Abstract file tab is selected.• User enters or browses to point to a Die Abstract file.• Press Library Manager Button to invoke IC Library Manager. • By default the same Die Abstract file will be selected in the IC Library Manager, as the file was just browsed to.• User selects options to use for IC library processing, and cml file is created. The name of the file is the same as die abstract file name with .cml extension. The Auto create button needs to be pressed in order to create the .cml file and attach it to the database. The Auto-create button will be disabled until the user has actually opened the Options form and pressed OK. • If CML file is created by mistake, press Remove CML button to remove CML file. By removing it and not creating another CML, or going to LEF option, user is back to default behavior.• The design name (read from the Die Abstract file, and becomes the component name) appears on the form.• User presses OK button to add the die to the drawing, or Cancel to abort command.• The die placement form appears, an image of the die appears on the cursor and the user can place the die into the SiP design.
Add Co-design Die from Die Abstract file (cml files to be created based on .ldf file, this is the 16.3 flow)• The Add Co-design Die command is invoked.• The New Design from Die Abstract file tab is selected.• User enters or browses to point to a Die Abstract file.• Press Library Manager Button to invoke IC Library Manager. • By default the same Die Abstract file will be selected in the IC Library Manager, as the file was just browsed to. Select option .ldf file. Browse to ldf file.• Use IC Library Manager the same way as it was used prior to 16.5. Exit library manager.• The design name (read from the Die Abstract file, and becomes the component name) appears on the form.• User presses OK button to add the die to the drawing, or Cancel to abort command.• The die placement form appears, an image of the die appears on the cursor and the user can place the die into the SiP design.
Update Co-design Die from Die Abstract File• The user must first invoke the Die Editor command.• When the Die Editor launches on the Component Selection form if a co-design component with Die Abstract co-design source is selected, a type in field or browse button can be used to select the new Die Abstract file from disk. If new file is not selected by default the method that was used previously to add or update the die will be used. If new die abstract file is selected, default would be to use simple case, as described above in Add Co-design. If user chooses to use IC Library Manager, press Library Manager Button.• Note that updating a co-design die from a new Die Abstract file will replace the existing die layout with exactly what is in the Die Abstract file. Thus any changes that were made to the die in SiP Layout, but not incorporated in the new Die Abstract file imported to update the die will be lost. Also note that the abstract is not incremental, and must include complete information about the die.• Offer options to compare the new Die Abstract only, without updating the die, update the die only without reporting changes, or update the die and report changes via Component Compare report. The default is to update the die from the Die Abstract file without reporting changes.• The form will include a note to the user informing him that updating the die from the Die Abstract file will replace the die layout with what is in the file, even if changes have been made to the die in SiP Layout that are not included in the Die Abstract file.
Menu and Command Line Access
The access to these commands is the same as in previous releases. The Add functionality can be launched by typing “add co-design die” in the command-line window, or through the “Add Co-design Die…” option of the Add menu. The Die Editor is invoked by typing “die editor” in the command-line window, or through the “Die” option of the “Edit” menu. On the add co-design form and on update die “Library Manager” button will be available, which will invoke IC Library Manager. To invoke ICLM from command line, “lef lib” should be typed (the same as in 16.3) or “ic lib” will also invoke library manager.
Note that the IC Library Manager in LEF library only mode is still available via the menu and command line. It will remain exactly the same as it was in 16.3.
Graphical User Interface
Add Co-design Die
As mentioned before, the default behavior for the add co-design die from Die Abstract would be adding library information stored in the Die Abstract itself without using IC Library Manager. There is no visual difference to the form for the add co-design die. The main difference is in when OK button becomes enabled:
The OK Button allows the adding of the die to proceed. This button is grayed out (disabled) until the following conditions are true -- a) The Die Abstract file has been read successfully; b) there is a valid Design Name present; c) the die component does not already exist. In prior releases OK button was disabled until the LEF Library manager has been configured with an appropriate LDF file and Library. This is no longer the case. By default, the Library information used is the information stored directly in Die Abstract file. The methodology used to determine die pins and RDL connection points.
As in the prior releases Library Manager Button is available to allow user to configure the IC Library Manager, if the user chooses to do so.
Die Editor Capability to Update Die from New Die Abstract
If you invoke the Die Editor command and select a co-design die to edit that has a Die Abstract file as its co-design source, the Die Editor Component Selection form appears as in Figure 1. This form shows that the co-design source is a Die Abstract file currently stored in the database. There is also a file browse button, with label (…), to select a new Die Abstract file from disk that contains an ECO from the IC tools. Selecting a new file in this way will update the die from that new Die Abstract file. This is all the same as it was in 16.3. New for 16.5 is that a Library Manager Button has been added to allow users to select the way they want to use library information:
The Die Editor Component Selection form shows the Co-Design Source as Die Abstract, with a browser button to select a new die abstract to use to update the die from an IC ECO, and Library Manager Button to allow user to configure IC Library Manager.
Die Abstract – Type in field that by default shows the current Die Abstract file is the <Current in Database>. This is a typable field where you can type in the name of a new Die Abstract file containing an ECO from the IC tool, which would then be used to update the die before launching the Die Editor. If you keep the default, <Current in Database>, when the Die Editor is launched after pressing the Next button, it loads the I/O driver cell information from the existing Die Abstract file contained in the database, rather than allowing update from a new Die Abstract. This is the same as in 16.3.… button – Opens a file browser to allow the user to browse for a new Die Abstract file, containing an ECO from the IC tool, from which to update the co-design die.Library Manager button - Allows user to configure the IC Library Manager.When the Next button is subsequently pressed, the ECO Die Abstract file will be read and the die updated from it before launching the Die Editor.
IC Library Manager (iclm) Other than the new radio button at the top, when LEF Library is chosen, the rest of the fields on the form behave exactly as in 16.3.
The Library settings section, including the LEF files list, of the form will be disabled when the Die Abstract option is chosen. Only the CML settings section will be enabled.
Browse… button – Opens a file browser to allow the user to browse for a new Die Abstract file, containing an ECO from the IC tool, from which to update the co-design die. Once a new die abstract is selected like this, it will be passed back to the Edit Die form to update that form so the newly selected file will be read to replace the previous version of the die.The CML settings behave exactly the same when the Die Abstract option is chosen as they did in 16.3 (and when the LEF Library option is chosen). The only difference is that only a single .cml file will be created, and it will be retained within the .sip database for future use when processing the die abstract.
Remove button -- Visible and active only if CML file is created and attached to the database. Press the button to remove CML as database attachment. By doing so, the library manager will process the die abstract using default algorithm. If using LEF/CML files option is the choice, select LEF Library radio button.Please share your findings with this capability.
Jerry "GenPart" Grzenia